JP2013074368A - Imaging apparatus and imaging method - Google Patents

Abstract

When estimating a temperature of a solid-state image sensor (image sensor) from an output value of an OB area pixel of the solid-state image sensor, a value obtained by excluding an output value of a defective pixel in the OB area from a pixel output value of the OB area is used. Thus, an imaging apparatus and an imaging method capable of improving the accuracy of temperature estimation of a solid-state imaging device are provided.
Position information of a defective pixel based on the temperature of a solid-state imaging device (CCD 101 that is an image sensor) including a light-shielding area (OB area) in the imaging area is obtained in advance, and the position information of the defective pixel is obtained based on the position at the time of shooting. Then, the temperature of the solid-state imaging device (CCD 101 which is an image sensor) is obtained, and the correction condition is changed based on the obtained temperature to correct the defective pixel. In addition, the temperature of the solid-state imaging device (CCD 101 which is an image sensor) is calculated by excluding defective pixels from the pixels in the light shielding region.
[Selection] Figure 2

Description

  The present invention relates to an imaging apparatus and an imaging method in which the temperature of a solid-state imaging device (image sensor) is estimated and defective pixels of the solid-state imaging device are corrected.

  In an image sensor such as a solid-state imaging device formed of a semiconductor such as a CCD or CMOS, an imaging surface (imaging plane) composed of a large number of pixels is formed by a large number of pixels composed of a semiconductor. In such an image sensor, local crystal defects occur in the semiconductor constituting the imaging surface due to manufacturing or aging.

  In addition, in such an image sensor, a defective pixel in which a constant bias voltage is always added to an imaging output corresponding to the amount of incident light due to the above-described local crystal defects of the semiconductor, and the like is output. It is known that image quality deterioration due to the image quality is caused. This image defect is called a white defect because it appears as a bright spot on the monitor screen when the image defect signal is processed as it is.

  Incidentally, in recent years, imaging apparatuses such as digital still cameras (hereinafter referred to as digital cameras) using such image sensors (CCD, CMOS, etc.) have become mainstream. Such an image sensor has an effective pixel area used for shooting out of the total pixel area and an OB area (optical black area) not used for shooting.

  In such an imaging device using an image sensor, defective pixel position information of the image sensor is stored in the memory in advance in the production / inspection process, and the defective pixel position information stored in the memory is used for correction of the defective pixel. Are known. For example, a technique for estimating the temperature of an image sensor from an output value of an OB area (optical black area) of the image sensor and applying correction conditions corresponding to the result to defective pixel correction is already known (for example, Patent Documents). 1).

  However, in recent digital camera image sensors, the reduction in the cell size accompanying the increase in the number of pixels increases the defective pixel occurrence rate in the OB region, and the number of pixels in the OB region used for estimation is small. There is a problem that the ratio of defective pixels in the OB region to the pixel output value is large, and the accuracy of estimating the temperature of the image sensor is lowered.

  Therefore, according to the present invention, when the temperature of the solid-state image sensor (image sensor) is estimated from the output value of the OB area pixel of the solid-state image sensor, the value obtained by excluding the output value of the defective pixel in the OB area from the pixel output value of the OB area. An object of the present invention is to provide an imaging apparatus and an imaging method that can improve the accuracy of temperature estimation of a solid-state imaging device.

  In order to achieve this object, an image pickup apparatus according to the present invention includes a solid-state image pickup device including a light-shielding region in an image pickup region, and a defective pixel position storage in which position information of a defective pixel according to the temperature of the solid-state image pickup device is obtained and stored in advance. And calculating the temperature of the solid-state image sensor based on the position information of the defective pixel stored in the defective pixel storage unit and changing the correction condition based on the calculated temperature at the time of photographing And defective pixel correction means for correcting the defective pixel based on the correction condition. In addition, the temperature calculating unit calculates the temperature of the solid-state imaging device by excluding defective pixels from the pixels in the light shielding region.

In order to achieve the above-described object, the imaging method of the present invention obtains in advance position information of a defective pixel depending on the temperature of a solid-state imaging device including a light-shielding area in the imaging area, and the position of the defective pixel at the time of shooting. An imaging method for obtaining the temperature of the solid-state imaging device based on information and correcting the defective pixel by changing a correction condition based on the obtained temperature,
The temperature of the solid-state imaging device is calculated by excluding defective pixels from the pixels in the light shielding region.

  According to the imaging apparatus and the imaging method according to the present invention, when the temperature of the solid-state imaging device (image sensor) is estimated from the output value of the OB region pixel of the solid-state imaging device, the defective pixel in the OB region is determined from the pixel output value of the OB region. Therefore, the accuracy of temperature estimation of the solid-state imaging device can be improved.

(A) is a front view of a digital camera which is an imaging apparatus according to the present invention, (b) is a rear view of the digital camera of (a), and (c) is a plan view of the digital camera of (a). FIG. 2 is a control circuit diagram of the digital camera shown in FIG. 1. It is a flowchart of the defect correction process of the digital camera shown in FIG. It is a figure explaining the OB area | region which is the calculation object in a defect correction process. FIG. 5 is a diagram illustrating a case where a defective pixel is included and a case where a defective pixel is not included (excluded) when the output average value of the OB region in FIG. It is explanatory drawing of the defective pixel correction coordinate registration area | region A, B, C of a defective pixel position memory | storage means. Another embodiment of the digital camera according to the present invention is an explanatory view schematically showing an RGB filter used in the digital camera. It is explanatory drawing which shows the number of the data of the address of the defective pixel stored in the defective pixel memory | storage means (data number of defective pixel) etc. by a table | surface. It is a flowchart which shows the defective pixel correction process content of this Example. It is explanatory drawing which showed the number of data (data number of a defective pixel) of the address (ordinate and horizontal coordinate of a solid-state image sensor) of the defective pixel stored in the defective pixel memory | storage means when the temperature of a solid-state image sensor is 10 degreeC. It is explanatory drawing which showed the number of data (the number of data of a defective pixel) of the address (vertical and horizontal coordinate of a solid-state image sensor) of the defective pixel stored in the defective pixel memory | storage means when the temperature of a solid-state image sensor is 20 degreeC. It is explanatory drawing which showed the number of data (the number of data of a defective pixel) of the address (ordinate and horizontal coordinate of a solid-state image sensor) of the defective pixel stored in the defective pixel memory | storage means when the temperature of a solid-state image sensor is 30 degreeC. It is explanatory drawing which showed the number of data (data number of a defective pixel) of the address (vertical coordinate of a solid-state image sensor) of the defective pixel stored in the defective pixel memory | storage means when the temperature of a solid-state image sensor is 40 degreeC. It is a flowchart at the time of displaying the temperature information of the solid-state image sensor calculated in the defective pixel correction process on the LCD monitor. FIG. 15 is an explanatory diagram illustrating an example in which temperature information calculated in the defective pixel correction process of FIG. 14 is displayed on an LCD monitor.

  A digital camera as an imaging apparatus according to the present invention will be described below with reference to the drawings.

[Constitution]
<Appearance structure of digital camera body>
Fig.1 (a)-FIG.1 (c) show the external appearance of the digital camera in embodiment of this invention. 1A is a front view of the digital camera, FIG. 1B is a rear view of the digital camera, and FIG. 1C is a plan view of the digital camera.

  As shown in FIGS. 1A to 1C, a release switch (release operation key) SW1, a mode dial switch (mode operation key) SW2, and a jog dial 1 switch (operation Key) SW3 is provided.

  Further, as shown in FIG. 1A, a strobe light emitting unit 3, a distance measuring unit 5, an optical finder F, and a lens barrel unit 7 that is a photographing lens are provided on the front surface of the digital camera body 2.

On the back of the digital camera body 2, as shown in FIG. 1B, an LCD monitor (display device, display unit) 10, jog dial 2 switch (operation key) SW4, zoom switch SW5 [TELE operation key], zoom switch SW6 [WIDE operation key], upper switch (up operation key) SW7, right switch (right operation key) SW8, OK switch (OK operation key) SW9, left switch (left operation key) SW10, down switch / macro switch (down) / Macro operation key) SW11, display switch (display operation key) SW12, delete switch (deletion operation key) SW13, menu switch (menu operation key) SW14, and power switch (power operation key) SW15. Further, a battery cover 4 is provided on the side surface of the digital camera body 2 as shown in FIG.
<Schematic configuration of system in digital camera body 2>
FIG. 2 shows a specific configuration of the lens barrel unit 7 shown in FIG. 1, and a CCD 101 (an image sensor that is a solid-state image sensor) on which a subject image is formed via the lens barrel unit 7, and a CCD 101. 1 shows a system configuration of a control circuit and the like for processing a video signal (image signal) from The CCD 101, the control circuit, and the like are provided in the digital camera body 2 shown in FIG.

The control circuit includes an F / E-IC 102 which is a front end IC circuit (image signal control circuit) shown in FIG. 2, an SDRAM 103 which is a memory (storage device), and a processor (digital control device) which is a device control means (device control circuit). (Still camera processor) 104.
-Lens barrel unit 7
The lens barrel unit 7 includes a zoom optical system, that is, a ZOOM optical (ZOOM optical unit) 7-1, a focus optical system, that is, a FOCAS optical system (FOCAS optical unit) 7-2, an aperture unit 7-3, a mechanical shutter unit 7-4, A motor driver 7-5 is provided.

In FIG. 2, the ZOOM optical system 7-1 includes a ZOOM lens 7-1a and a ZOOM motor 7-1b that drives the ZOOM lens 7-1a in the optical axis direction. The FOCAS optical system 7-2 includes a FOCAS lens 7-2a and a FOCAS motor 7-2b that drives the FOCAS lens 7-2a in the optical axis direction. The aperture unit 7-3 includes an aperture 7-3a and an aperture motor 7-3b that drives the aperture 7-3a. The mechanical shutter unit 7-4 includes a mechanical shutter 7-4a and a mechanical shutter motor 7-4b that drives the mechanical shutter 7-4a. Each of the motors 7-1b to 7-4b is driven by a motor driver 7-5. The motor driver 7-5 is driven and controlled by a drive signal from the processor 104.
・ CCD101
The CCD 101 forms a subject image incident through each photographing lens system of the lens barrel unit 7 on the light receiving surface and outputs a subject image signal to the F / E-IC 102.
・ F / E-IC102
The F / E-IC 102 corrects the intensity of the input signal and the CDS correlated double sampling 102-1 that takes a difference in signal level according to the incident light to the CCD 101 based on the subject image signal incident from the CCD 101. The AGC 102-2 includes an A / D conversion unit 102-3 that converts an analog signal into a digital signal. Then, the F / E-IC 102 outputs the digital signal converted by the A / D conversion unit 102-3 to the CCD1 signal processing block 104-1.
SDRAM 103
The SDRAM 103 stores RAW-RGB image data (RAW-RGB data), YUV image data, and JPEG image data obtained via the processor 104.
Processor 104
The processor 104 is a CCD 1 signal processing block 104-1, a CCD 2 signal processing block 104-2, a defective pixel correction block 104-3 A serving as defective pixel correction means, and a control means (control device) that substantially controls each part. It has a CPU block 104-3. The processor 104 also includes a LOCAL SRAM 104-4, a USB block 104-5, a serial block 104-11, a JPEG / CODEC block JPEG compression / decompression block 104-7, and a RESIZE block 104-8. The processor 104 further includes a TV signal display block 104-9 for converting the TV signal display block image data into a video signal for display on a display device such as a liquid crystal monitor / TV, a memory card controller block, and a memory for recording captured image data. It has a memory card controller block 104-10 for controlling the card. These blocks are connected to each other with the bus line code omitted.
(Function of each part of processor 104 and other configuration of control circuit)
The F / E-IC 102 includes a TG (timing signal generation unit) 102-4 that drives the CCD 101, a CDS (correlated double sampling unit) 102-1 that samples an electrical signal (analog RGB image signal) output from the CCD 101, AGC (Analog Gain Control Unit) 102-2 that adjusts the gain of the signal sampled by the CDS 102-1 and the signal gain-adjusted by the AGC 102-2 are converted into a digital signal (hereinafter referred to as “RAW-RGB data”). A / D converter 102-3.

The signal control processing in the processor 104 is performed via the TG 102-4 by the vertical synchronizing signal VD / horizontal synchronizing signal HD output from the CCD1 signal processing block 104-1. That is, the CCD1 signal processing block 104-1 of the processor 104 outputs the screen horizontal synchronizing signal HD and the screen vertical synchronizing signal VD to the TG 102-4 of the F / E-IC 102, and F / F in accordance with these synchronizing signals. RAW-RGB data, which is a digital signal output from the A / D converter 102-3 of the E-IC 102, is captured. The RAW-RGB data captured by the CCD1 signal processing block 104-1 is stored in the SDRAM 103.
CCD2 signal processing block 104-2
The SDRAM 103 stores YUV data (YUV format image data) converted by the CCD2 signal processing block 104-2, and further stores JPEG format image data compressed by the JPEGCODEC block 104-7. Is done.

The YUV of the YUV data expresses the color with the luminance data Y, the difference between the color difference luminance data and the blue B component data, and the difference V between the luminance data and the red R component data.
Operation key (operation key) unit K_U (SW1-SW15)
The operation key unit K_U (SW1-SW15) includes a release switch SW1, a mode dial switch SW2, a telephoto zoom switch [on the external surface of the digital camera body 2 shown in FIGS. TELE] SW5, wide-angle zoom switch [WIDE] SW6, upper switch SW7, right switch SW8, OK switch SW9, left switch SW10, lower switch / macro switch SW11, display switch SW12, delete switch SW13, menu switch SW14, power switch SW15 or the like. The operation key unit K_U (SW1-SW15) inputs an operation instruction signal according to the photographer's operation to the processor 104 via the SUB-CPU 109.
CPU block 104-3
The CPU block 104-3 controls the F / E-IC 102 and the motor driver 7-5 of the lens barrel unit 7. Further, the CPU block 104-3 controls the strobe circuit 114 to emit illumination light from the strobe light emitting unit 3. In addition to this, the CPU block 104-3 also controls the distance measuring unit 5. Further, the CPU block 104-3 is connected to the SUB-CPU 109 of the processor 104, and the SUB-CPU 109 performs display control of the sub LCD 1 in FIG. 2 (not shown in FIG. 1) via the LCD driver 111. Moreover, the CPU block 104-3 controls the operation of the audio recording circuit 115-1 and the audio reproduction circuit 116-1.

The sub CPU 109 is further connected to an AF LED 8, a strobe LED 9, a remote control light receiving unit 6, an operation key unit K_U (SW1-SW15) including switches SW1 to SW15, and a buzzer 113.
Defect pixel correction block (defective pixel correction means) 104-3A
This defective pixel correction block 104-3A has a correlation table between the average OB area output value of the CCD 101 and the temperature of the CCD 101, that is, a characteristic line indicating the correlation between the average OB area output value of the CCD 101 and the temperature of the CCD 101 as shown in FIG. The defective pixel correction process of the CCD 101 is performed using a table for obtaining F1 and F2.

  Further, a correlation table between the average OB area output value of the CCD 101 and the temperature of the CCD 101, that is, a table for obtaining the characteristic line F1 indicating the correlation between the average OB area output value of the CCD 101 and the temperature of the CCD 101 as shown in FIG. , And stored in advance in a built-in memory 120 or a table memory (table storage device) for storing temperature correlation tables such as ROM 108 or LOCAL SRAM 104-4. The characteristic line F2 in FIG. 5 is for comparison with the characteristic line F1.

  In addition, in the production / inspection process of the digital camera, the defective pixel position information corresponding to the temperature of the CCD 101 (image sensor) is stored in the table memory (table storage device) for storing the temperature correlation table and stored in the table memory. The stored defective pixel position information is used for correcting defective pixels.

  That is, when the power switch SW15 of the digital camera is turned on, the CPU block 104-3 displays the table of the characteristic line F1 obtained and stored in advance in the above-described temperature correlation table storage table memory (table storage device). The pixel information is read and stored in the RAM 107, and at the same time, the defective pixel position information (defective pixel address) corresponding to the temperature of the CCD 101 (image sensor) previously obtained and stored in the table memory (table storage device) for storing the temperature correlation table. Is stored in a RAM 107 as defective pixel storage means, and defective pixel position information corresponding to the temperature of the CCD 101 is used for correction of the defective pixel at the time of photographing by the CCD 101. In the following description, the case where the built-in memory 120 is used as the above-described table memory (table storage device) for storing the temperature correlation table will be described for convenience.

The RAM 107 is provided with defective pixel correction coordinate registration areas A, B, and C. In this defective pixel correction coordinate registration area A, defective pixels when the temperature TEMP is lower than the threshold TH2 are registered (stored), and in the defective pixel correction coordinate registration area B, the temperature TEMP is higher than the threshold TH2 and lower than the threshold TH2. Defective pixels are registered (stored), and defective pixels when the temperature TEMP is higher than the threshold value TH3 are registered (stored) in the defective pixel correction coordinate registration area C. It is also possible to provide a defective pixel memory separately from the RAM 107 and store the defective pixel correction coordinate registration areas A, B, and C in the defective pixel memory. Note that the table memory (table storage device) for storing the temperature correlation table is also provided with defective pixel correction coordinate registration areas similar to the defective pixel correction coordinate registration areas A, B, and C provided in the RAM 107.
・ USB block 104-5
The USB block 104-5 is connected to the USB connector 122, and the serial block 104-11 is connected to the RS-232C connector 123-2 via the serial driver circuit 123-1.
TV signal display block 104-9
The TV signal display block 104-9 is connected to the LCD monitor 10 via the LCD driver 117, and a video AMP (amplify) for converting the video signal output from the TV signal display block 104-9 into 75Ω impedance. A) The video jack camera is connected via 118 to a video jack 119 for connecting to an external display device such as a TV.
Memory card controller block 104-10
The memory card controller block 104-10 is connected to a contact with the card contact of the memory card slot 121.
LCD driver 117
The LCD driver 117 functions to drive the LCD monitor 10 and convert the video signal output from the TV signal display block 104-9 into a signal to be displayed on the LCD monitor 10.

  The LCD monitor 10 is used for monitoring the state of a subject before photographing, confirming a photographed image, and displaying image data recorded in the memory card or the built-in memory 120.

  When the photographer sets the mode dial SW2 to the photographing mode and turns on the power SW 15, the camera is activated in the photographing mode. When this operation is detected by the control program of the ROM 108, a control signal is output to the motor driver 7-5, the lens barrel unit 7 is moved forward from the front of the digital camera body 2 to the photographing position, and the CCD 101, F / E. -Activate the IC 102, the processor 104, and the like.

  By directing the lens barrel unit 7 toward the subject in this state, the subject image is imaged on the light receiving surface of each pixel of the CCD 101 and the electrical signal analog RGB image signal output from the CCD 101 is transmitted through the F / E-IC 102. It is converted into bit-bit RAW-RGB data.

  This RAW-RGB data is taken into the CCD1 signal processing block 104-1 of the processor 104 and stored in the SDRAM 103. The RAW-RGB image data read from the SDRAM 103 is converted into YUV data that can be displayed by the CCD2 signal processing block 104-2, and then the YUV data is stored in the SDRAM 103.

  Thereafter, the YUV data read from the SDRAM 103 is sent to the LCD monitor via the TV signal display block 104-9, and a photographed image is displayed. At the time of monitoring when an image is displayed on the LCD monitor 10 described above, one frame is read out in a time of 1/30 seconds by thinning out the number of pixels by the CCD1 signal processing block 104-1. The monitoring here is a state in which a photographed image is displayed in real time on the LCD monitor 10 functioning as an electronic viewfinder, and the release switch SW1 is not operated by the photographer.

  The photographer can confirm the photographed image by displaying the photographed image on the LCD monitor 10. The captured image can also be displayed on the external TV television via the cable from the video signal display block 104-9 and the video AMP 118 from the video jack 119.

The CCD1 signal processing block 104-1 calculates an AF automatic focus evaluation value, an AE automatic exposure evaluation value, and an AWB auto white balance evaluation value based on the captured RAW-RGB data.
(AF processing)
The AF evaluation value by the CCD1 signal processing block 104-1 is calculated by, for example, the output integrated value of the high frequency component extraction filter or the integrated value of the luminance difference between adjacent pixels. When in the in-focus state, the edge portion of the subject is clear, so the high frequency component is the highest. By utilizing this, at the time of focus detection operation during AF operation, an AF evaluation value at the position of the FOCAS lens 7-2a of the FOCAS optical system 7-2 is obtained, and the point where the high frequency component becomes the highest is detected as the focus detection position. As described above, an AF operation (AF process) is executed.

That is, in this AF operation (AF processing), the CCD1 signal processing block 104-1 obtains an AF evaluation value at the position of the FOCAS lens 7-2a and focuses the point where the high-frequency component of this AF evaluation value is highest. The CPU block 104-3 of the processor 104 controls the operation of the FOCAS motor 7-2b via the motor driver 7-5 so that the detection position is reached, and the FOCAS lens 7-2a is moved to the optical axis by the motor driver 7-5. Drive in the direction.
(AE evaluation value, AWB evaluation value)
The AE evaluation value and the AWD evaluation value by the CCD1 signal processing block 104-1 are calculated from the integrated values of the RGB values in the RAW-RGB data. For example, the CCD1 signal processing block 104-1 equally divides the screen corresponding to the imaging surface (light receiving surface) of all the pixels of the CCD 101 into a plurality of 256 areas. That is, by dividing the imaging surface (light receiving surface) of all the pixels of the CCD 101 into 16 in the horizontal direction and 16 in the vertical direction, the screen corresponding to the imaging surface (light receiving surface) of all the pixels in the CCD 101 is divided into 256 areas. To do. Also, the CCD1 signal processing block 104-1 calculates the RGB integration of each of the divided 256 areas.
(AE treatment)
The control program existing in the ROM 108 is read by the processor 104 and resides in the RAM 107, and the calculated RGB integrated value is read. Then, this control program calculates the brightness of each of the plurality of areas on the imaging surface (imaging surface) of the CCD 101 in the AE process, and determines the appropriate exposure amount of each of the plurality of areas of the CCD 101 from the calculated brightness distribution. To do. Since a known technique can be adopted for this AE process, its detailed description is omitted.
(AWB processing)
Based on the determined exposure amount, the number of electronic shutters of the exposure condition CCD 101, the aperture value of the aperture unit 7-3, and the like are set. In the AWB process, a control value that matches the color of the light source of the subject is determined from the RGB distribution. By this AWB processing, the white balance when the CCD2 signal processing block 104-2 is converted into YUV data is adjusted. The AE process and the AWB process described above are continuously executed during the monitoring.
<Shooting process by operating the release switch SW1>
When the release switch SW1 is fully pressed from the half-pressed state and the still image shooting operation is started during the monitoring operation described above, the AF operation and the still image recording process that are the focus position detection operations are performed.
(Shooting operation)
In other words, the CPU block 104-3 of the processor 104 controls the operation of the motor driver 7-5 based on the control program stored in the ROM 108 and releases the FOCAS by the motor driver 7-5 when the release switch SW1 is pressed halfway down. By driving the motor 7-2b, the FOCAS lens 7-2a is moved in the optical axis direction to be focused. After this focusing, AE processing is performed, and exposure of the CCD 101 is started.

  The CPU block 104-3 of the processor 104 performs the above-described AE process, and closes the mechanical shutter 7-4a by a drive command from the ROM 108 control program to the motor driver 7-5 when the exposure of the CCD 101 starts. Accordingly, an analog RGB image signal for a still image is output from the CCD 101, and the analog RGB image signal is converted into RAW-RGB data by the A / D conversion unit 102-3 of the F / E-IC 102.

This RAW-RGB data is taken into the CCD1 signal processing block 104-1 of the processor 104, YUV converted by the CCD2 signal processing block 104-2, and stored in the SDRAM 103. In addition, this YUV data is read from the SDRAM 103, converted into a size corresponding to the number of recording pixels in the RESIZE block 104-8, and compressed into image data in the JPEG format or the like in the JPEGCODEC block 104-7. The compressed image data in JPEG format or the like is written back to the SDRAM 103 and then stored in a medium such as the memory card 121-1 via the memory card controller block 104-10.
[Action]
A method of changing the defective pixel correction condition from the OB pixel value in the OB area in the digital camera having such a configuration will be described with reference to the flowchart shown in FIG.

  Here, the OB area is an area that is shielded by the light shielding film and is not used for photographing out of the total pixel area (imaging area) of the imaging surface of the CCD (image sensor) 101, and is called an optical black area. The imaging area includes an OB area that is shielded by the light shielding film and is not used for imaging, and an effective pixel area (effective imaging area) that is used for imaging.

  When a camera power supply (not shown) is turned on by operating the power switch SW15, a control operation by the processor (control device) 104 in FIG. 2 is started. At this time, the CPU block 104-3 of the processor (control device) 104 reads the table of the characteristic line F1 previously obtained and stored in the table memory (table storage device) for storing the temperature correlation table and stores it in the RAM 107. Let As a result, the CPU block 104-3 also detects defective pixel position information (defective) corresponding to the temperature of the CCD 101 (image sensor) stored in advance in the table memory (table storage device) for storing the temperature correlation table. Pixel address) is read and stored in the RAM 107 as defective pixel storage means.

  Further, when a camera power supply (not shown) is turned on by such an operation of the power switch SW15, a photographing operation by the block 104-3 of the CPU of the processor (control device) 104 of FIG. 2 in step S10 of FIG. Control is started. That is, when the camera power source (not shown) is turned on, the CPU block 104-3 starts the above-described photographing operation, that is, AF processing, AE processing, and AWB processing, and the motor driver based on the control program in the ROM 108. 7-5 is controlled to drive the FOCAS motor 7-2b by the motor driver 7-5, and the FOCAS lens 7-2a is moved in the optical axis direction to perform a focusing operation.

  Accordingly, the CPU block 104-3 controls the operation of the CCD1-signal processing block 104-1, and causes the CCD1-signal processing block 104-1 to capture the image signal from the CCD 101 via the F / E-IC 102. . The CPU block 104-3 displays the subject image on the LCD monitor 10 via the TV signal display block 104-9 and the LCD driver 117 based on the captured image signal.

  From this state, when the release switch SW1 is pressed and pressed halfway down to the full press, the CPU block 104-3 determines that a photographing request is made in step S11, and proceeds to step S12. In this step S12, the CPU block 104-3 controls the operation of the CCD1-signal processing block 104-1, and causes the CCD1-signal processing block 104-1 to capture the image signal from the CCD 101 via the F / E-IC 102. The process proceeds to step S13. At this time, the CPU block 104-3 transfers only the pixels obtained by excluding the defective pixels from the horizontal / vertical OB pixels from the image signal captured by the CCD1-signal processing block 104-1 to the CCD2-signal processing block 104-2. The integration is performed and the process proceeds to step S14. Here, the horizontal / vertical OB pixel means a pixel in the OB area.

  In step S14, the block 104-3 of the CPU determines whether or not the horizontal / vertical OB pixel value is equal to or greater than a certain value (threshold value) TH. In this determination, when the horizontal / vertical OB pixel value is smaller than a certain value TH, the process proceeds to step S15. In this determination, if the horizontal / vertical OB pixel value is equal to or greater than a certain value TH, it is determined as a defective pixel temperature scratch and is not subject to integration, and the process proceeds to step S16.

  Here, the horizontal / vertical OB is a horizontal OB area and a vertical OB area of the entire screen (imaging surface) of the CCD 101. Here, assuming that an imaging area used for exposure during imaging in the entire screen (imaging surface) of the CCD 101 is an effective imaging surface (effective pixel region), the horizontal OB region is in the horizontal direction of the entire screen (imaging surface) of the CCD 101. The vertical OB area exists in the left and right parts of the effective imaging surface (effective pixel area), and the vertical OB area exists in the upper and lower parts of the effective imaging surface (effective pixel area) in the vertical direction of the entire screen (imaging surface) of the CCD 101.

  The horizontal / vertical OB pixel value means a horizontal OB pixel value and a vertical OB pixel value. The horizontal OB pixel value is a pixel value in the horizontal OB area, and the vertical OB pixel value is a pixel value in the vertical OB area. The defective pixel temperature flaw means a defective pixel having high temperature dependency, that is, a defective pixel whose output value changes depending on the temperature of the image sensor (described later).

  Then, the CPU block 104-3 counts the number of pixels that were not to be integrated in step S14 in step S16 and stores them in the RAM 107, and integrates (calculates) the pixel values of the other pixels in step S15. The program is stored in the RAM 107, and the process proceeds to step S17.

  In step S17, the CPU block 104-3 determines whether or not all horizontal and vertical OB pixels have been integrated, that is, whether or not there is a calculation target pixel in the OB area. In this determination, if it is determined that all the horizontal / vertical OB pixels to be integrated have not been integrated, the process proceeds to step S17-1, and it is determined that all the horizontal / vertical OB pixels to be integrated have been integrated. If yes, the process proceeds to step S18.

  In step S17-1, the CPU block 104-3 accumulates pixel values in the horizontal / vertical OB areas and stores them in the RAM 107, excluding (excludes) pixels that are determined as defective pixel temperature scratches and are not subject to integration. Then, the process proceeds to step S18.

  In step S18, the CPU block 104-3 calculates the average value of the output pixel values in the horizontal / vertical OB area, and stores the calculated average value of the output pixel values in the horizontal / vertical OB area in the RAM 107. The process proceeds to S19. The equation for calculating the average value of the output pixel values in the horizontal and vertical OB areas is “integrated value / total number of OBs to be integrated−D defective pixel number”.

  In step S19, the CPU block 104-3 determines whether the CCD 101 (solid-state image sensor) is a correlation table between the OB area output average value of the CCD 101 stored in advance in step S18 and the temperature of the CCD 101, which is the solid-state image sensor. The temperature TEMP of the image sensor) is calculated and stored in the RAM 107, and the process proceeds to step S20.

  In step S20, the CPU block 104-3 compares the temperature TEMP of the CCD 101 (image sensor), which is a solid-state imaging device, with the predetermined thresholds TH2 and TH3, and performs the branch processing of steps S21 to S23 based on this comparison. . That is, when the temperature TEMP of the CCD 101 (image sensor) that is a solid-state image sensor is lower than TH2 in step S20, the process proceeds to step S21, and the temperature TEMP of the CCD 101 (image sensor) that is a solid-state image sensor is TH2 and TH3 in step S20. If the temperature TEMP of the CCD 101 (image sensor), which is a solid-state imaging device, is higher than TH3 in step S20, the process proceeds to step S23.

  In step S <b> 21, the CPU block 104-3 controls the operation of the defective pixel correction block 104-3 </ b> A so as to correct the defective pixel registered in the defective pixel correction coordinate registration area A of the RAM 107. In step S22, the defective pixel correction block 104-3A causes the defective pixel correction block 104-3A to execute the defective pixel correction of the condition 2, that is, the correction of the defective pixel registered in the defective pixel correction coordinate registration area B of the RAM 107. In step S23, the defect pixel correction block 104-3A is caused to execute the defective pixel correction of the condition 3, that is, the correction of the defective pixel registered in the defective pixel correction coordinate registration area C of the RAM 107, and the process ends. This defective pixel correction can be performed by the CCD1 signal processing block 104-1 without providing the defective pixel correction block 104-3A. In addition, since a specific method for correcting defective pixels is the same as that of a known technique, description thereof is omitted.

In this way, RAW-RGB image data in which defective pixel correction processing has been performed from the image signal captured by the CCD1 signal processing block 104-1 is recorded in the SDRAM.
(Supplementary explanation)
FIG. 4 is a diagram for explaining the calculation target (accumulation target) in step S13 shown in FIG.

  FIG. 4 shows a pixel image when the calculation process (integration process) is performed in step S14 shown in FIG. The white squares indicate defective pixels of the CCD 101 (image sensor) that is a solid-state image sensor. In a CCD (image sensor) which is a solid-state imaging device in recent years, the defective pixel occurrence rate in the OB region is increasing due to the cell size reduction accompanying the increase in the number of pixels. As shown in FIG. 4, since the number of pixels in the horizontal / vertical OB area (horizontal OB area and vertical OB area) is much smaller than the effective pixel area, defective pixels are included when integrating pixel values and the like. If this is the case, the effect on the results will be greater.

  FIG. 5 is a diagram illustrating a case where a defective pixel is included and a case where a defective pixel is not included (excluded) when an output average value of an OB area is obtained. That is, FIG. 5 shows the case of calculating the pixel output average value in the OB area including the defective pixels in the horizontal / vertical OB area shown in FIG. (Excluded) is shown by the characteristic line F1 in (b).

  In general, it is said that a defective pixel having a high temperature dependency such as a temperature flaw is doubled when the temperature of a CCD (image sensor) which is a solid-state imaging device is increased by 10 ° C.

  For this reason, as shown by the characteristic line F2 in FIG. 5A, when calculating the pixel output average value of the OB region, if the defective pixel is included, the average value increases nonlinearly as the temperature increases. The correlation with the temperature is lost. On the contrary, as shown by the characteristic line F1 in FIG. 5B, when calculating the OB area output average value without including the defective pixels in the OB area, the influence of the value of the defective pixels is eliminated. Linearly correlates with temperature.

  In FIG. 5, the OB output average value when there is a defective pixel in the OB region is OBAVE-A, and the OB output average value when there is no defective pixel in the OB region or when the defective pixel is not included is compared with OBAVE-A. Is. As shown in FIG. 5, when there is no defective pixel in the OB area, the OB output average value changes linearly with a constant slope as shown by the output characteristic line F1, and when there is a defective pixel in the OB area. The change in the OB output average value increases as the temperature rises as indicated by the output characteristic line F2.

  As can be seen from the output characteristic line F1, the temperature calculated from the average value OBAVE-A when there is no defective pixel in the OB region or when the defective pixel is not included is 40 ° C.

  Further, as can be seen from the output characteristic line F2, when there is a defective pixel in the OB region, the temperature calculated from the average value OBAVE-A is 30 ° C.

  Comparing this temperature, when there is a defective pixel in the OB region, the temperature of the average value OBAVE-A is estimated to be 10 ° C. with the temperature of the average value OBAVE-A when there is no defective pixel in the OB region (not included). It can be seen that there is an error. This estimation error increases as the temperature of the CCD (image sensor), which is a solid-state imaging device, increases from FIG.

  FIG. 6 is a diagram for explaining defective pixel correction conditions in steps S21, S22, and S23 of FIG.

  The magnitude relationship between the thresholds TH2 to TH3 shown in FIG. 6 is TH2 <TH3. As shown in FIG. 6, when the calculated temperature TEMP is smaller than the threshold value TH2, the defective pixel registered in the defective pixel correction coordinate registration area A is corrected. When the calculated temperature TEMP is between the threshold value TH2 and the threshold value TH3, the defective pixel registered in the defective pixel correction coordinate registration areas A and B is corrected. When the calculated temperature TEMP is larger than the threshold value TH3, the defective pixels registered in all the defective pixel correction coordinate registration areas A, B, and C are corrected. In this way, the correction condition of the defective pixel is changed according to the calculated temperature.

  7 to 9 show another embodiment of the imaging apparatus according to the present invention. And FIG. 7 is explanatory drawing which shows typically the RGB filter used for a digital camera. FIG. 8 is an explanatory diagram showing, in a table form, the number of defective pixel addresses (number of data of defective pixels) stored in the RAM 107 in each priority correction pixel group PN. FIG. 9 is a flowchart showing the defective pixel correction processing contents of this embodiment.

  In FIG. 7, a CCD 101 is a solid-state imaging device that converts a formed subject image into an electrical signal (image data) and outputs it. The CCD 101 has an entire light receiving surface divided into a grid-like area called a pixel (hereinafter also referred to as a pixel 101a (see FIG. 7)), and an image composed of a set of pixel data that is digital data. Data is output as an electrical signal.

  The CCD 101 is provided with color filters (RGB, CYM, etc.) so as to form a Bayer array in each divided area (pixel). In the embodiment, as shown in FIG. (Hereinafter referred to as “RGB filter”) is arranged. Therefore, the CCD 101 outputs an electrical signal (analog RGB image signal) corresponding to the three primary colors of RGB from each pixel 101a. The CCD 101 can also be configured with a CMOS image sensor or the like as a solid-state image sensor.

  1 and 2 is directed toward the subject, the subject image incident on the ZOOM lens 7-1a of the lens barrel unit 7 in FIG. 2 is formed on the light receiving surface of each pixel of the CCD 101. Image. Then, an electrical signal (analog RGB image signal) corresponding to the subject image output from the CCD 101 is input to the A / D converter 102-3 via the CDS 102-1 and AGC 102-2, and the A / D converter 102. -3 to 12-bit (RAW) RGB data.

  This RAW-RGB data is taken into the CCD1 signal processing block 104-1 and stored in the SDRAM 103. The RAW-RGB data read from the SDRAM 103 is converted into YUV data (YUV signal) by the CCD2 signal processing block 104-2, and then stored in the SDRAM 103 as YUV data.

  Then, the YUV data read from the SDRAM 103 is sent to the liquid crystal monitor (LCD) 10 via the TV signal display block 104-9, and the photographed image is displayed on the liquid crystal monitor (LCD) 10. At the time of monitoring in which a captured image is displayed on the liquid crystal monitor (LCD) 10, one frame is read out in a time of 1/30 seconds by thinning out the number of pixels.

  During this monitoring operation, the photographed image is only displayed on the liquid crystal monitor (LCD) 10 functioning as an electronic viewfinder, and the release switch SW1 is not yet pressed (including half-pressed).

By displaying the photographed image on the liquid crystal monitor (LCD) 10, the photographer can confirm the composition for photographing the still image.
(Defective pixel and its detection method)
In an imaging device (such as the CCD 101 described above) used in a digital still camera, not all light receiving elements are formed with the same performance in the semiconductor manufacturing process, and some light receiving elements are defective. May end up. A pixel corresponding to the light receiving element in which this defect has occurred is hereinafter referred to as a defective pixel.

  Therefore, a device such as a digital still camera equipped with an image sensor may have a predetermined number or less of defective pixels in the image sensor. For this reason, in the digital camera, the ordinate and abscissa (address) of the defective pixel on the CCD 101 (hereinafter referred to as defective pixel data) are stored in the RAM 107 or the like in advance, and the defect stored in the RAM 107 or the like in the imaging data at the time of shooting. A defective pixel correction process is performed on the pixel data corresponding to the pixel address.

  For this defective pixel, for example, a pure white image having an AE evaluation value that is an average value of the luminance values of the entire image of about 128 is acquired, and in each pixel data of the image data, a difference from the luminance value of 128 is predetermined. It can be detected by judging whether it is larger than the value. Here, those having a luminance value lower than 128 are referred to as black scratches, and those having a luminance value higher than 128 are referred to as white scratches.

  In addition to the above-described defective pixels, there are also defective pixels that have poor dark current characteristics (temperature scratches). This temperature flaw is a dynamic defect factor in which the influence increases as the dark current increases or accumulates, that is, as the temperature of the image sensor increases or the exposure time increases.

  For this reason, a defective pixel having this temperature flaw usually does not cause a problem with exposure of about 1 second, but as the exposure time becomes longer, the increase in dark current increases, which is superimposed on the image data and becomes a bright spot on the image. Looks like. This is what appears as dotted star-like noise in an image obtained by long exposure photography such as night scene photography. There are about 60 defective pixels with temperature flaws for an image sensor with 3 million pixels, and the addresses of the individual defective pixels can be stored in the RAM 107 or the like. However, since defective pixels with temperature flaws are dynamic defect factors as described above, they must be corrected by imaging parameters such as exposure time.

The defective pixel having the temperature flaw is detected by, for example, acquiring a true-dark image by shielding light and determining whether the luminance value is larger than a predetermined value in each pixel data of the image data. Can do. The defective pixel having the temperature flaw can be corrected by estimating the temperature in the same manner as in the first embodiment.
(Example of defect pixel correction method)
Correction of defective pixels is basically performed by the following method. First, in the digital camera, the data of the defective pixel address (vertical and horizontal coordinates on the CCD 101) detected as described above and stored in the RAM 107 or the like is registered (stored or stored) in the RAM (storage unit) 107. .

  Thereafter, when the release switch SW1 (see FIG. 1) is pressed down and the image data acquired by the CCD 101 is propagated through the processor 104 as described above, the image data (image generation that is image data in the generation process) is generated. Data) is sent to a CCD2 signal processing block 104-2 used as a defective pixel correction unit. In the CCD2 signal processing block 104-2, pixel data corresponding to the address of the defective pixel registered in the RAM (storage unit) 107 is read out from the image data (each pixel data) and viewed with the surrounding RGB filters. Interpolate with pixel data corresponding to the same color.

  Basically, interpolation is performed by using an average value of pixel data on both sides adjacent to each other in the horizontal direction of a focused defective pixel (defective pixel to be corrected) as pixel data of the focused defective pixel. Here, when the noticed defective pixel is located at the left end or the right end in the image data, the pixel data adjacent to the horizontal direction is corrected as the pixel data of the noticed defective pixel.

Further, even when two defective pixels of the same color viewed in the RGB filter are arranged in the horizontal direction (hereinafter also referred to as a defective pixel of two consecutive pixels), the correction can be made. When correcting the focused defective pixels of the two consecutive pixels, pixel data in which one defective pixel is adjacent to the other defective pixel on the opposite side is set as pixel data of the one defective pixel, and the other defective pixel is Interpolation is performed by using pixel data adjacent to the defective pixel as the pixel data of the other defective pixel. Here, when the defective pixel of the continuous two pixels of interest is located at the left end or the right end in the image data, the pixel data for two pixels of the pixel data adjacent in the horizontal direction and the pixel data adjacent thereto are Correction is performed by using pixel data of the defective pixels of the two consecutive pixels of interest.
(Defective pixel correction process)
In the following description, the number of defective pixels that can be registered (stored) in the RAM (storage unit) 107 (registration limit number) is set to 500 for the defective pixel correction processing for easy understanding.

  Further, the exposure time is used as a criterion for determining the change in the influence of defective pixels. The exposure time serving as the determination reference is determined using the correction determination value when the luminance value (defective pixel level) of a true-dark image (dark image) in the light shielding area of the CCD 101 is used as the correction determination value.

  That is, when a defective pixel is detected in the CCD 101, a pixel image (pixel data) in the acquired image (dark image image data) is obtained by capturing (photographing) a dark image with darkness (dark image image data). When the brightness value (defective pixel level) that appears as a bright spot in the acquired image (image data) is used as a correction judgment value, the exposure time is determined using this correction judgment value. The setting conditions are determined.

  For example, in the embodiment, if the defective pixel level (luminance value) is 240 or more, it appears as a bright spot in the image (image data) when the exposure time is 2 seconds. For this reason, when the defective pixel level (luminance value) is 240 or more, the correction judgment value is 240 to 255.

  If the defective pixel level (luminance value) is 220 or more, it appears as a bright spot in the image (image data) when the exposure time is 4 seconds. Therefore, when the defective pixel level (luminance value) is 220 or more, the correction determination value is 240 to 250.

Further, if the defective pixel level (luminance value) is 200 or more, it appears as a bright spot in the image (image data) when the exposure time is 8 seconds. From this, when the defective pixel level (luminance value) is 200 or more, the correction judgment value is set to 200 to 239,
If the defective pixel level (luminance value) is 180 or more, it appears as a bright spot in the image (image data) when the exposure time is 16 seconds. The correction judgment value is 180 to 199.

  In the embodiment, the higher the defective pixel level (luminance value) is, the higher the correction priority is the defective pixel (temperature scratch). Note that the luminance value as the defective pixel level is an output value with the full scale of the output being 255, and indicates that the larger the value, the larger (higher) output.

  The number of defective pixels depends on the characteristics of the image sensor (sensor). For example, in CMOS, it is said that 10 times more defective pixels appear than CCD even under the same conditions. For this reason, in the state where the sensor (CCD 101 in the embodiment) is actually mounted on the digital still camera (the digital camera in the embodiment), the number of defective pixels appearing in the exposure of 2 seconds and the number of defective pixels appearing in the exposure of 4 seconds. As such, it is possible to statistically grasp the number of defective pixels that appear at each set exposure time, and determine that it is sufficient to correct all of the defective pixels that appear according to the exposure time. The number is set as the number of corrected pixels according to the exposure time. For this reason, it can be said that the correction judgment value for the exposure time, that is, each numerical value of the defective pixel level (luminance value) is a guideline for setting the number of correction pixels according to the exposure time. In this defective pixel correction process, defective pixels are corrected by the number of corrected pixels corresponding to the exposure time in order from the pixel with the highest defective pixel level.

  In this embodiment, the correction pixel number is 200 when the exposure time is 2 seconds, the correction pixel number is 500 when the exposure time is 4 seconds, and the correction pixel number is 700 when the exposure time is 8 seconds. The number of corrected pixels when the exposure time is 16 seconds is 1000 (see FIG. 8).

  That is, statistically, the number of pixels with a defective pixel level (luminance value) of 240 to 255 is 200 or less, the number of pixels with a defective pixel level (luminance value) of 220 to 255 is 500 or less, and defective pixels This means that the number of pixels with a level (luminance value) of 200 to 255 is 700 or less, and the number of pixels with a defective pixel level (luminance value) of 180 to 255 is 1000 or less.

  For the defective pixel correction processing with the number of corrected pixels corresponding to the set exposure time, the processor 104 converts the detected defective pixel address data (vertical and horizontal coordinates on the CCD 101) into defective defect data as defective pixel data. In association with the pixel level and the set exposure time, it is stored in the RAM 107 as follows. In the embodiment, as described later, defective pixel data to be appropriately registered in the RAM 107 is stored in the RAM 107. However, any memory can be used as long as the processor 104 can store and read data as appropriate.

  First, as shown in FIG. 8, 200 pixels are detected as defective pixels in order from the pixel having the highest defective pixel level among all the pixels of the CCD 101, and the address data of the defective pixel in the first priority correction pixel group P1 is detected. Is stored in the RAM 107. The 200 defective pixels detected as the first priority correction pixel group P1 become 200 defective pixels that are corrected when the exposure time is 2 seconds.

  Next, among all the pixels of the CCD 101, 500 pixels are detected as defective pixels in order from the pixel having the highest defective pixel level, and 200 pixels of the first priority correction pixel group P1 are detected from the detected 500 pixels. Are removed as defective pixels and stored in the RAM 107 as address data of defective pixels in the second priority correction pixel group P2. This is because, for example, in the process of detecting 500 pixels in order from the pixel with the highest defective pixel level among all the pixels of the CCD 101, among the 200 defective pixels in the first priority correction pixel group P1 among them, This is done by selecting a defective pixel level lower than the low defective pixel level. Therefore, 200 defective pixels of the first priority correction pixel group P1 are subtracted from 500 pixels having a high defective pixel level among all the pixels of the CCD 101 as defective pixels of the second priority correction pixel group P2. The remaining 300 pixels are detected. The 300 defective pixels detected as the second priority correction pixel group P2 are corrected when the exposure time is 4 seconds by adding 200 defective pixels of the first priority correction pixel group P1. Defective pixels. In such a defective pixel correction process, the number of defective pixels that can be registered (stored) in the RAM 107 is set as a defective pixel having a higher correction priority in order from the highest defective pixel level, as will be described later. In the embodiment, since the number of defective pixels that can be registered (stored) in the RAM 107 is 500, the 500 defective pixels that are corrected when the exposure time is 4 seconds directly become defective pixels having a high correction priority.

  Next, 700 pixels are detected as defective pixels in order from the pixel having the highest defective pixel level among all the pixels of the CCD 101, and 200 pixels of the first priority correction pixel group P1 are detected from the detected 700 pixels. The defective pixels and the 300 defective pixels of the second priority correction pixel group P2 are selected as defective pixels and stored in the RAM 107 as address data of defective pixels of the third priority correction pixel group P3. For example, in the process of detecting 700 pixels in order from the pixel having the highest defective pixel level among all the pixels of the CCD 101, among the 300 defective pixels in the second priority correction pixel group P2 among them, This is done by selecting a defective pixel level lower than the low defective pixel level. Therefore, as the defective pixels of the third priority correction pixel group P3, the 200 defective pixels of the first priority correction pixel group P1 and the second defective pixels are selected from 700 pixels having a high defective pixel level among all the pixels of the CCD 101. The remaining 200 pixels obtained by subtracting 300 defective pixels of the priority correction pixel group P2 are detected. The 200 defective pixels detected as the third priority correction pixel group P3 are obtained by adding the 200 defective pixels of the first priority correction pixel group P1 and the 300 defective pixels of the second priority correction pixel group P2. Thus, 700 defective pixels are corrected when the exposure time is 8 seconds.

  Next, 1000 pixels are detected as defective pixels in order from the pixel having the highest defective pixel level among all the pixels of the CCD 101, and 200 pixels of the first priority correction pixel group P1 are detected from the detected 1000 pixels. Of the second priority correction pixel group P2 and 300 defective pixels of the third priority correction pixel group P3 are selected as defective pixels, and the fourth priority correction pixel group P4 is selected. The data is stored in the RAM 107 as defective pixel address data. This is because, for example, in the process of detecting 1000 pixels in order from the pixel with the highest defective pixel level among all the pixels of the CCD 101, among the 200 defective pixels in the third priority correction pixel group P3 among them, This is done by selecting a defective pixel level lower than the low defective pixel level. Therefore, as the defective pixels of the fourth priority correction pixel group P4, the 200 defective pixels of the first priority correction pixel group P1, the second defective pixel level, the 1000 defective pixels among all the pixels of the CCD 101, the second The remaining 300 pixels are detected by subtracting the 300 defective pixels of the priority correction pixel group P2 and the 200 defective pixels of the third priority correction pixel group P3. The 300 defective pixels detected as the fourth priority correction pixel group P4 are the 200 defective pixels in the first priority correction pixel group P1, the 300 defective pixels in the second priority correction pixel group P2, and the third priority pixels. By adding the 200 defective pixels of the correction pixel group P3, 1000 defective pixels are corrected when the exposure time is 16 seconds.

  Since the number of correction pixels is set as described above, in each defective pixel of each priority correction pixel group PN (N = 1 to 4), the correction judgment value, that is, the setting is set among all the pixels of the CCD 101. Defective pixel level (luminance value) in the range of the defective pixel level (luminance value) as a guideline of the defective pixel level that is included without leaking, but smaller than the defective pixel level (luminance value) as a guideline of setting May be included.

  The processor 104 of the embodiment uses the address data (see FIG. 8) of each priority correction pixel group PN (N = 1 to 4) stored in the RAM 107 as described above, that is, defective pixel correction processing using each defective pixel data. I do. FIG. 9 is a flowchart showing the details of the defective pixel correction process of the embodiment executed by the processor 104.

  In step S1, the set exposure time is acquired, and the process proceeds to step S2. In this step S1, when the release switch SW1 is depressed to start the shooting operation, information on the exposure time at the time of shooting that can be obtained thereby is acquired. The exposure time may be set by the processor 104 according to the shooting mode, the atmosphere at the shooting site, or the like, or may be set by operating the operation key unit K_U (SW1-SW15). Since the exposure time at the time of shooting is determined when it is started, information on the exposure time is acquired with the start of the shooting operation.

  In Step S2, following the acquisition of the set exposure time in Step S1, it is determined whether or not the acquired exposure time is 8 seconds or more. If Yes, the process proceeds to Step S3. If No, Step S4 is performed. Proceed to In step S2, the length (numerical value) of the exposure time acquired in step S1 is determined for switching the content of the defective pixel correction process, that is, for switching the number of defective pixel correction operations by the CCD2 signal processing block 104-2. doing. As described above, this is because the number of correction pixels corresponding to the exposure time is set in advance and the number of defective pixels (registration limit number) that can be registered (stored) in the RAM 107 of the CCD2 signal processing block 104-2. Depends on the limits. In the embodiment, the number of defective pixels (registration limit number) that can be registered in the RAM 107 is 500, whereas the number of corrected pixels when the exposure time is 4 seconds is set to 500 and the exposure time is 8 seconds. Since the number of corrected pixels is set to 700, the number of corrected pixels set to have an exposure time of 8 seconds or more exceeds the registration limit number, so the process proceeds to step S3 in order to perform the defective pixel correction operation twice. Since the number of correction pixels set to the exposure time of 4 seconds or less is equal to or less than the registration limit number, the process proceeds to step S4 in order to perform the defective pixel correction operation once.

  In step S3, following the determination that the exposure time in step S2 is 8 seconds or longer, correction of defective pixels having a high correction priority is executed, and the flow proceeds to step S4. In this step S3, since it is determined in step S2 that the exposure time is 8 seconds or more, there are more defective pixels than the number of defective pixels (registration limit number) that can be registered in the RAM 107 of the CCD2 signal processing block 104-2. Therefore, the CCD2 signal processing block 104-2 corrects the defective pixels of the registration limit number of the RAM 107 from the order of the highest correction priority, that is, the order of the defective pixel level (luminance value). In the embodiment, since the registration limit number of the RAM 107 is 500, the CCD2 signal processing block 104-2 has the address data of 200 defective pixels in the first priority correction pixel group P1 and the second priority correction pixel group P2. The address data of 300 defective pixels is read from the RAM 107 and registered (stored) in the RAM 107 of the CCD2 signal processing block 104-2.

  Thereafter, the CCD2 signal processing block 104-2 reads out the pixel data corresponding to the address of the defective pixel registered in the RAM 107 in the received image data (each pixel data thereof), and looks at the surrounding RGB filters. By interpolating with pixel data corresponding to the same color, a total of 500 defective pixels of 200 defective pixels in the first priority correction pixel group P1 and 300 defective pixels in the second priority correction pixel group P2 Perform the correction. Here, since all the address data of the 500 defective pixels can be registered in the RAM 107, the CCD2 signal processing block 104-2 performs a defective pixel correction operation once, and the 500 correction pixels having a high correction priority. All defective pixels can be corrected. Note that if the number of defective pixels in each priority correction pixel group PN (N = 1 to 4) does not correspond to the registration limit number in the RAM 107, the registration limit number that can be registered in order from the highest correction priority. It is desirable to store the address data of the defective pixels in the RAM 107 in advance in a state enabling registration in the RAM 107.

In step S4, following the determination that the exposure time in step S2 is not more than 8 seconds or the execution of correction of defective pixels having a high correction priority in step S3, preparation for defective pixel correction according to the exposure time is performed. To go to step S5. In this step S4, in order to correct the defective pixels having the number of correction pixels corresponding to the exposure time acquired in step S1, the address data of each priority correction pixel group PN (N = 1 to 4) is appropriately read from the RAM 107, By registering (storing) in the RAM 107, preparation for defective pixel correction according to the exposure time is performed (this is referred to as process A). That is, a substantial correction pixel number is set.
(Defective pixel correction processing in high-speed shooting processing)
Here, when high-speed shooting processing is required (for example, continuous shooting) depending on the shooting mode, shooting atmosphere, etc., the above-described defective pixel correction processing is repeated in the CCD2 signal processing block 104-2 (described above). When the defective pixel correction operation is performed twice in the embodiment, the processing time of the defective pixel correction becomes a problem. For this reason, in the defective pixel correction processing, when high-speed shooting processing such as continuous shooting is required, it is assumed that pixels with a high defective pixel level (defective pixels with a high correction priority) are preferentially corrected. The defective pixel correction operation in the processing block 104-2 is performed only once. This is because a pixel having a high defective pixel level is a pixel that tends to appear in an image (image data) as a defective pixel. In this case, for example, when the defective pixel correction operation is executed in step S3 in the flowchart of FIG. 9, the defective pixel correction process can be terminated without proceeding to step S4. Accordingly, when high-speed shooting processing such as continuous shooting is required, it is possible to correct defective pixels that are likely to appear in an image (image data) while reducing the processing time required for defective pixel correction.
(Operation of defective pixel correction processing)
In this defective pixel correction process, as described above, when the number of defective pixels to be corrected in the image sensor (CCD 101) exceeds the number of defective pixels that can be registered in the RAM 107, the registration contents in the RAM 107 are rewritten. That is, since the defective pixel correction operation in the CCD2 signal processing block 104-2 is repeated while changing the registered contents of the defective pixel data in the RAM 107, all defective pixels of the image sensor (CCD 101) can be corrected. . More specifically, in the embodiment, while the registration limit number that can be registered (stored) in the RAM 107 is 500, the number of correction pixels required according to the exposure time is the correction pixel number when the exposure time is 2 seconds. Is 200, the number of correction pixels when the exposure time is 4 seconds is 500, the number of correction pixels when the exposure time is 8 seconds is 700, and the number of correction pixels when the exposure time is 16 seconds is 1000 ( Therefore, when the exposure time is 2 seconds or 4 seconds, as the defective pixel correction operation in the CCD2 signal processing block 104-2, the correction pixel number is corrected according to the exposure time acquired in step S1. If the exposure time is 8 seconds or 16 seconds, 500 defective pixels with high correction priority are corrected in step S3 as the defective pixel correction operation in the first CCD2 signal processing block 104-2. As the defective pixel correction operation in the CCD2 signal processing block 104-2 for the second time following step S3, the correction pixel number 500 of the defective pixel correction executed in step S3 is calculated from the correction pixel number corresponding to the exposure time acquired in step S1. Correction of the remaining correction pixel number obtained by subtracting is performed in step S5. Thus, even when the number of defective pixels that can be registered in the RAM 107 of the CCD2 signal processing block 104-2 is exceeded (in the embodiment, when the exposure time is 8 seconds or 16 seconds), the number of pixels exceeding the number is 2 Since the correction is performed by the defective pixel correction operation in the CCD2 signal processing block 104-2 of the second time (multiple times depending on the setting conditions), regardless of the relationship between the number of defective pixels that need to be corrected and the registration limit number of the RAM 107, All defective pixels of the image sensor (CCD 101) can be corrected.

  Further, since the number of pixels to be corrected is changed according to the exposure time, it is possible to correct only the necessary number of correction pixels according to the exposure time, in other words, it is possible to appropriately correct without excess or deficiency, It is possible to prevent image quality deterioration due to insufficient correction or overcorrection of defective pixels. This is because if defective pixels appearing in the image (image data) are not corrected due to insufficient correction, the defective pixels may be recognized on the image. If a non-appearing pixel is corrected as a defective pixel, the spatial resolution is obtained by substantially smoothing the periphery of the pixel even though it is not a problem pixel (and its periphery) in the image before correction. This is because there is a risk of causing deterioration or the like.

  Furthermore, since pixels with a high defective pixel level are preferentially corrected, pixels that are easily recognized as defective pixels on the image (image data) can be preferentially corrected, so that the image quality can be improved more efficiently. be able to.

  For this reason, in the digital camera described above, it is possible to appropriately correct all defective pixels to be corrected regardless of the registration limit number in the RAM 107. As a result, the quality of an image (image data) taken under conditions where dark current increases or accumulates, for example, when the temperature of the image sensor (CCD 101) rises or the exposure time is long is improved. Can be made.

  In the above-described embodiment, an example in which the exposure criterion is set as the criterion for determining the change in the influence of the defective pixel and the number of corrected pixels according to the exposure time is set is shown. As long as the correction pixel number is set based on a factor that changes the influence of the above as a criterion, it is not limited to the embodiment. For example, the defective pixel correction process can be performed based on the setting of the number of correction pixels according to the ISO sensitivity. In this case, as with the exposure time, the number of defective pixels that appear with an ISO sensitivity of 100 and an ISO sensitivity of 200 when the sensor (CCD 101 in the embodiment) is actually mounted on a digital still camera (digital camera in the embodiment). To statistically grasp the number of defective pixels that appear at each set ISO sensitivity, such as the number of defective pixels that appear, and to correct all the defective pixels that appear according to the ISO sensitivity It is sufficient to set the number that can be determined to be sufficient as the number of correction pixels according to the ISO sensitivity. As an example of this, the number of correction pixels with an exposure time of ISO 100 is 200, the number of correction pixels with ISO 200 is 500, the number of correction pixels with ISO 400 is 700, and the number of correction pixels with ISO 800 is 1000. Thus, defective pixel correction processing can be performed in the same manner as in the case where the number of correction pixels is set corresponding to the exposure time described above. Even in this case, the control unit 28 uses the data of the detected defective pixel address (vertical and horizontal coordinates on the CCD 101) for defective pixel correction processing with the number of corrected pixels according to the set ISO sensitivity. Stored in the RAM 107.

  From this point of view, the defective pixel correction process can be performed more finely by performing the defective pixel correction process from the combination of the exposure time and the ISO sensitivity. In this case, it is desirable to reduce the number of defective pixel addresses (vertical and horizontal coordinates on the CCD 101) stored in the RAM 107 (number of defective pixel data) and the like. 10 to 13 show the number of defective pixel addresses (vertical and horizontal coordinates on the CCD 101) stored in the RAM 107 when the defective pixel correction process is performed based on the combination of the exposure time and the ISO sensitivity (the number of defective pixels). It is an explanatory diagram for reducing the number of data.

  10 to 13 show the addresses of defective pixels stored in the RAM 107 (ordinate and abscissa on the CCD 101) when the temperature of the CCD 101 is 10 ° C, 20 ° C, 30 ° C, and 40 ° C, respectively. The number of data (number of defective pixel data) is shown respectively. Moreover, in FIGS. 10 to 13, the vertical axis represents the exposure time (2 s, 4 s, 8 s, 16 s) for explaining the combination for the number of correction pixels according to the exposure time, and the horizontal axis represents the ISO sensitivity setting. The ISO sensitivity (100, 200, 400, 800) for explanation of the combination for the number of corrected pixels corresponding to is shown.

  When the variable according to the exposure time is x, the variable according to the ISO sensitivity setting is y, and the variable according to the temperature of the CCD 101 is z, the address of the defective pixel stored in the RAM 107 (CCD101 The number of pieces of data (upper and lower horizontal coordinates) (the number of defective pixel data) can be represented by an address indicated by a correction pixel group Pxyz as shown in FIGS.

  The relationship between the correction pixel group Pxyz and the variables x, y, z will be described with reference to FIGS.

  10 to 13, “x = 1” is set when the exposure time is 2 s, “x = 2” is set when the exposure time is 4 s, “x = 3” is set when the exposure time is 8 s, and “x” is set when the exposure time is 16 s. = 4 ". 10 to 13, when the ISO sensitivity is 100, “y = 1” is set, when the ISO sensitivity is 200, “y = 2” is set, and when the ISO sensitivity is 300, “y = 3” is set, and the ISO sensitivity is set. When y is 400, “y = 4”.

  When the temperature of the CCD 101 is 10 ° C., “z = 1”, when the temperature of the CCD 101 is 20 ° C., “z = 2”, and when the temperature of the CCD 101 is 30 ° C., “z = 3”. When the temperature of the CCD 101 is 40 ° C., “z = 4”.

  Therefore, for example, P111 in FIG. 10 indicates that x, y, and z of the correction pixel group Pxyz are x = 1 (exposure time 2 s), y = 1 (ISO 100), and z = 1 (the temperature of the CCD 101 is 10 ° C.). Shows the address. For example, in FIG. 11, in P342, x, y, and z of the correction pixel group Pxyz are x = 3 (exposure time 8 s), y = 4 (ISO 800), and z = 2 (the temperature of the CCD 101 is 20 ° C.). Shows the address. The number of data (number of defective pixel data) of the defective pixel address (vertical and horizontal coordinates on the CCD 101) is stored in the address indicated by the correction pixel group Pxyz.

  As described above, FIGS. 10 to 13 are tables illustrating the number of data (number of defective pixel data) of defective pixel addresses (vertical and horizontal coordinates on the CCD 101) stored in the RAM 107 in each correction pixel group Pxyz. It is. 10 to 13 are explanatory diagrams showing all combinations in the case where variables have ranges of 1 ≦ x ≦ 4, 1 ≦ y ≦ 4, and 1 ≦ z ≦ 4.

By the way, when there are four variables x, y, and z in this way, each correction pixel group Pxyz has 4 × 4 × 4 = 64 patterns. (An actual digital still camera may have a range of 1 ≦ x ≦ 9, 1 ≦ y ≦ 7, 1 ≦ z ≦ 5, and thus requires a larger number of correction pixel groups Pxyz.)
In order to reduce the number of such correction pixel groups Pxyz, “(correction pixel group Pxyz for exposure time 1 (2, 3, 4,...) Stages = t (t + k, t + 2k, t + 3k at the temperature of the image sensor)”. ,..., Correction pixel group Pxyz for degrees Celsius = correction pixel group Pxyz for analog gain 1 (2, 3, 4,.

  When the combination lines indicated by A to J as shown in FIGS. 10 to 13 are considered, the portion of the correction pixel group Pxyz related to each combination line A to J can be formed with the same correction pixel group. For example, the shaded cells (P431, P341, P422, P332, P242, P413, P323, P233, P143, P314, P224, P134) of the combination line F can be formed as the same correction pixel group.

  FIGS. 10 to 13 are views showing the concept in the case where the concept of the same correction pixel group is applied to other correction pixel groups. By doing so, the 64 correction pixel groups Pxyz can be compressed into 10 ways A to J.

  In the first embodiment described above, only the defective pixel correction process has been described. However, the present invention is not limited to the defective pixel correction process. FIGS. 14 and 15 show an example in which the temperature information of the CCD (image sensor) 101 calculated in the defective pixel correction process is displayed on the LCD monitor 10.

  In step S10 of FIG. 14, the block 104-3 of the CPU is block 104-3 of the CPU of the processor (control device) 104 of FIG. 2 when the camera power supply (not shown) is turned on by the operation of the power switch SW15. Shooting control by is started. When a camera power supply (not shown) is turned on, the CPU block 104-3 starts a monitoring operation as in step S10-1 in FIG. 14, and proceeds to step S10-2. In this monitoring operation, the CPU block 104-3 starts the above-described photographing operation, that is, AF processing, AE processing, and AWB processing, and controls the operation of the motor driver 7-5 based on the control program in the ROM 108, thereby driving the motor driver 7. -5 drives the FOCAS motor 7-2b and moves the FOCAS lens 7-2a in the optical axis direction to perform a focusing operation. Accordingly, the CPU block 104-3 controls the operation of the CCD1 signal processing block 104-1, and causes the CCD1 signal processing block 104-1 to capture the image signal from the CCD 101 via the F / E-IC 102. The CPU block 104-3 displays the subject image on the LCD monitor 10 via the TV signal display block 104-9 and the LCD driver 117 based on the captured image signal.

  In step S <b> 10-2, the CPU block 104-3 determines whether or not to display temperature information of the CCD (image sensor) 101 that is a solid-state imaging device on the LCD monitor 10. This determination is made based on whether or not the camera setting is “display sensor temperature” when the camera power is turned on by operating the power switch SW15 in step S10. For this setting, the menu switch (menu operation key) SW14 is operated to display a number of items of camera settings on the LCD monitor 10, and among these items, “display sensor temperature” is displayed on the switches SW7 to SW10, etc. It is done by selecting by.

  In step S10-2, the CPU block 104-3 loops back to step S10-1 when the temperature information is not displayed, and executes steps S13 to S19 of the first embodiment when the temperature information is displayed. . In step S19, the temperature (TEMP) of the image sensor is calculated as in the flow described in FIG. 3, and the process proceeds to step S19-1.

  In step S19, the CPU block 104-3 displays the temperature information calculated in step 19 (S19) on the LCD monitor 10 as shown in FIG. In FIG. 15, a mark Mt for displaying temperature information is displayed on the LCD monitor 10, and a temperature display bar Bt is displayed on the LCD monitor 10. When the temperature calculated in step S19 is low, the black portion of the temperature display bar Bt is short as shown in FIG. 15 (a), and when the temperature is high, the temperature is shown in FIG. 15 (b). The black portion of the display bar Bt is displayed for a long time. As a result, the photographer can grasp the temperature of the CCD (image sensor) 101. When the temperature is high, the photographer can recognize that noise and defective pixels are generated and image quality is deteriorated.

  As described above, the imaging apparatus according to the embodiment of the present invention includes a solid-state imaging device (CCD101) including a light-shielding region (OB region) in an imaging region, and defective pixels depending on the temperature of the solid-state imaging device (CCD101). Defective pixel position storage means (RAM 107) for which position information has been obtained and stored in advance, and the solid-state imaging device (CCD 101) based on the position information of the defective pixel stored in the defective pixel storage means (RAM 107) at the time of photographing. ) And a temperature calculation means (CPU block 104-3) for changing the correction condition based on the calculated temperature, and a defective pixel correction means (defect for correcting the defective pixel based on the correction condition). Pixel correction block 104-3A). In addition, the temperature calculation means (CPU block 104-3) calculates the temperature of the solid-state imaging device (CCD 101) by excluding defective pixels from the pixels in the light shielding area.

  According to this configuration, when the temperature of the solid-state imaging device (CCD 101 as the image sensor) is estimated from the output value of the OB region pixel of the solid-state imaging device (CCD 101), the defective pixel in the OB region is determined from the pixel output value of the OB region. Since the value excluding the output value is used, the accuracy of temperature estimation of the solid-state imaging device (CCD 101) can be improved.

  In the imaging apparatus according to the embodiment of the present invention, the temperature calculation means (CPU block 104-3) stores a plurality of correction conditions in advance and switches the correction conditions according to the temperature calculation result.

  According to this configuration, since the correction conditions are switched according to a plurality of correction conditions stored in advance in a memory or the like and the result of temperature calculation, the correction conditions can be changed easily and quickly.

  Furthermore, in the imaging apparatus according to the embodiment of the present invention, the correlation table between the average value of the pixels in the light shielding region excluding defective pixels among the pixels in the light shielding region and the temperature of the solid-state imaging device (CCD 101) is It is stored in advance in the defective pixel position storage means (RAM 107). In addition, the temperature calculation means (CPU block 104-3) obtains an average value of the output of the light shielding region by excluding pixels having a predetermined threshold value or more from the pixels of the light shielding region during photographing. Based on the correlation table of the average value of the obtained output, the average value of the pixels in the light-shielding area stored in advance in the defective pixel position storage means (RAM 107), and the temperature of the solid-state imaging device (CCD 101), The temperature of the solid-state imaging device (CCD 101) is calculated by excluding the defective pixels.

  According to this configuration, when the temperature of the solid-state imaging device (CCD 101 as the image sensor) is estimated from the output value of the OB region pixel of the solid-state imaging device (CCD 101), defective pixels among the pixels in the light shielding region are excluded. Since the temperature of the solid-state imaging device (CCD101) is calculated using a correlation table between the average value of pixels in the light-shielding region and the temperature of the solid-state imaging device (CCD101), the accuracy of temperature estimation of the solid-state imaging device (CCD101) is increased. Can be improved. That is, as shown by the characteristic line F2 in FIG. 5A, when calculating the pixel output average value of the OB region, if the defective pixel is included, the average value increases nonlinearly as the temperature increases. Correlation with temperature is lost. However, as in this embodiment, as shown by the characteristic line F1 in FIG. 5B, when calculating the average output value of the OB area, it is possible to calculate the defect without including the defective pixels in the OB area. The influence of the pixel value is eliminated, and the temperature is linearly correlated.

  Further, in an imaging apparatus such as a digital still camera, a technique for storing defective pixel position information of an image sensor in a memory in advance in a production / inspection process and correcting defective pixels based on defective pixel position information recorded at the time of photographing As an application, there is a technology that corrects pixel defects while saving the memory capacity used by grouping and registering pixel defect position information that occurs every exposure time of long-time exposure. It has been. However, the technology that corrects the pixel defect while saving the memory capacity to be used by grouping and registering the pixel defect position information that occurs every exposure time of long-time exposure, the temperature of the image sensor and the analog gain Does not consider changes. Although the occurrence of pixel defects in the image sensor greatly affects the exposure time, it also has a significant effect on the temperature and analog gain of the image sensor, so that influence must be taken into consideration.

  In consideration of such points, in the imaging apparatus according to the embodiment of the present invention, the defective pixel position storage unit (RAM 107) corresponds to a combination of the temperature, exposure time, and ISO sensitivity of the solid-state imaging device (CCD 101). The positions of the defective pixels are stored without overlapping. The defective pixel correction means (defective pixel correction block 104-3A) is a temperature of the solid-state imaging device (CCD 101) based on the position information of the defective pixels stored in the defective pixel position storage means (RAM 107). Defective pixel correction is performed according to the exposure time and ISO sensitivity.

  According to this configuration, when the defective pixel position information of the image sensor is stored in the memory in advance in the production / inspection process, the occurrence of the pixel defect of the image sensor is not only influenced by the exposure time but also by the effect of temperature and analog gain. Considering this, even when the temperature of the image sensor and the ISO sensitivity setting change due to grouping, appropriate pixel defect correction can be performed while saving the memory capacity to be used.

  Furthermore, in the imaging apparatus according to the embodiment of the present invention, the display device (LCD monitor 10) displays the calculated temperature information of the solid-state imaging device (CCD 101).

  According to this configuration, the photographer can grasp the temperature state of the image sensor at any time by displaying the estimated temperature of the solid-state imaging device (the CCD 101 which is an image sensor) on the LCD monitor 10 and notifying the photographer. . When the temperature is high, the photographer takes measures such as turning off the power of the camera and lowers the temperature of the solid-state imaging device (the CCD 101 as the image sensor), so that it is possible to take an image with less noise and defective pixels.

  In the imaging method according to the embodiment of the present invention, the position information of the defective pixel according to the temperature of the solid-state imaging device (the CCD 101 that is the image sensor) including the light shielding area (OB area) in the imaging area is obtained in advance. At the time of shooting, the temperature of the solid-state imaging device (CCD 101 that is an image sensor) is obtained based on the position information of the defective pixel, and the correction condition is changed based on the obtained temperature to correct the defective pixel. In addition, the temperature of the solid-state imaging device (CCD 101 which is an image sensor) is calculated by excluding defective pixels from the pixels in the light shielding region.

  According to this imaging method, when the temperature of the solid-state imaging device (the CCD 101 as the image sensor) is estimated from the output value of the OB region pixel of the solid-state imaging device (CCD 101), the defective pixel in the OB region is determined from the pixel output value of the OB region. Therefore, the accuracy of the temperature estimation of the solid-state imaging device (CCD 101) can be improved.

10 ... LCD monitor (display device)
101 ... CCD (solid-state image sensor)
107... RAM (defective pixel position storage means)
104 ... Digital still camera processor (processor)
104-3... CPU block (temperature calculation means)
104-3A ... defective pixel correction block (defective pixel correction means)

JP 2009-33550 A

Claims (6)

A solid-state imaging device including a light-shielding region in the imaging region;
A defective pixel position storage means for preliminarily obtaining and storing defective pixel position information according to the temperature of the solid-state imaging device;
A temperature calculating unit that calculates a temperature of the solid-state image sensor based on the position information of the defective pixel stored in the defective pixel storage unit and changes a correction condition based on the calculated temperature at the time of shooting;
An imaging device comprising: defective pixel correction means for correcting the defective pixel based on the correction condition,
The temperature calculation means calculates the temperature of the solid-state image sensor by excluding defective pixels from the pixels in the light shielding region.   The imaging apparatus according to claim 1, wherein the temperature calculation unit stores a plurality of correction conditions in advance and switches the correction conditions according to a temperature calculation result.   2. The image pickup apparatus according to claim 1, wherein a correlation table between an average value of pixels in the light-shielding region excluding defective pixels among pixels in the light-shielding region and a temperature of the solid-state image sensor is stored in the defective pixel position storage unit in advance. The temperature calculating means obtains an average value of the output of the light shielding region by excluding pixels having a pixel value equal to or greater than a predetermined threshold among the pixels of the light shielding region at the time of shooting, and outputs the calculated output. The solid-state imaging is performed by excluding defective pixels from the pixels in the light-shielding region based on a correlation table between the average value and the average value of the pixels in the light-shielding region and the temperature of the solid-state imaging device stored in advance in the defective pixel position storage unit. An imaging device characterized by calculating a temperature of an element.   The defective pixel position storage means stores the position of the defective pixel in accordance with a combination of temperature, exposure time, and ISO sensitivity of the solid-state image sensor without overlapping, and the defective pixel correction means stores the defective pixel. 2. The imaging according to claim 1, wherein defective pixel correction is performed according to the temperature, exposure time, and ISO sensitivity of the solid-state imaging device based on the position information of the defective pixel stored in a position storage means. apparatus.   The imaging device according to claim 1, wherein the calculated temperature information of the solid-state imaging device is displayed on a display device. The position information of the defective pixel due to the temperature of the solid-state imaging device including the light-shielding region in the imaging region is obtained in advance, and the temperature of the solid-state imaging device is obtained based on the position information of the defective pixel at the time of shooting. An imaging method for correcting the defective pixel by changing a correction condition based on temperature,
An imaging method, wherein a temperature of the solid-state imaging device is calculated by excluding defective pixels from pixels in the light shielding region.