JP2010041437A - Imaging apparatus, control method thereof, and program - Google Patents

Abstract

It is possible to improve the result of blacking processing by generating a black image from which random noise is removed while leaving noise inherent to an image sensor.
An imaging apparatus (1) divides a black image into a plurality of divided images under the control of a system control unit (113), and detects the presence or absence of noise extending in one direction for each of the divided images. The presence or absence of intrinsic noise in the element 103 is detected. Further, under the control of the system control unit 113, the imaging device 1 detects the extending direction of the inherent noise for each of the divided images in which the inherent noise is detected. Further, the imaging apparatus 1 performs isotropic two-dimensional smoothed image processing for each of the black image divided images as long as it is a divided image in which no inherent noise is detected, under the control of the system control unit 113. In addition, the imaging apparatus 1 performs anisotropic two-dimensional smoothed image processing that does not smooth the detected inherent noise if it is a divided image in which inherent noise is detected, and a black image formed of the divided images after image processing. Is used for blacking processing.
[Selection] Figure 1

Description

  The present invention relates to an imaging apparatus, a control method thereof, and a program.

  2. Description of the Related Art Conventionally, there are image pickup apparatuses that pick up still images and moving images with an image pickup element such as a CCD or a CMOS image sensor, and record and reproduce them. In this imaging apparatus, fixed pattern noise may occur when the conditions during imaging are high sensitivity, long exposure, or high temperature, and the image quality of the captured image may deteriorate. Fixed pattern noise is noise inherent to the image sensor that is generated due to local crystal defects in the semiconductor constituting the image sensor or dark current noise.

  For example, it is known that a large amount of dark current noise is generated in the image sensor when the condition during imaging is the above-described condition. Dark current noise is generated because the image sensor has the property of converting not only light energy but also heat energy into an electrical signal, and has a temperature dependence that doubles when the temperature rises by about 10 ° C. ing. For example, the temperature of the imaging device may increase at a portion where the current consumption is large, such as an output amplifier, and the dark current noise may partially increase due to the partial temperature increase. As an example of this partial dark current noise affecting the image quality of captured images, when shooting a night scene with high-sensitivity long-second exposure, the portion that appears black because it is actually not illuminated appears bright in colors close to magenta There are black floats.

  Further, dark current noise is generated not only in a pixel portion that receives a subject image and performs photoelectric conversion, but also in a vertical transfer path that transfers the converted charge. The dark current noise generated in the vertical transfer path appears as streaky black floating in the vertical direction in the captured image. In addition, the following three are mentioned as the feature of the streaky black floating in the captured image. The first point is that even a small noise equivalent to random noise generated uniformly in an image is conspicuous. The second point is that since the dark current noise increases as the signal charge is placed longer in the vertical transfer path, a noise level difference tends to occur in the vertical direction of the screen. The third point is that there are variations in dark current noise level and transfer efficiency for each vertical transfer path, and stripe-like shading unevenness tends to occur in the horizontal direction of the screen. In other words, streaky black floats tend to be noticeable even in the magnitude of random noise, and are easily generated in the horizontal or vertical direction.

  On the other hand, fixed pattern noise due to local crystal defects in the semiconductor constituting the imaging device is caused by white defects appearing in dots due to defective pixels, and signal charges are transferred through defective portions in the vertical transfer path. In other words, there are line flaws that appear linearly in the vertical direction as the transfer direction.

In the imaging apparatus, in order to remove the various fixed pattern noises described above from the captured image, a black image is captured with exactly the same imaging conditions as when capturing the subject image except that the shutter is closed and the light is blocked. Black subtraction processing is performed to subtract the black image from. However, when performing black subtraction processing, it becomes impossible to ignore the influence of random noise that is uniformly included in a black image, so it is necessary to remove random noise while leaving fixed pattern noise. Patent Documents 1 and 2 are known as conventional techniques for removing random noise while leaving fixed pattern noise in a black image for performing this blacking process. In Patent Document 1, by performing high-frequency component suppression processing on a low-level pixel signal that is equal to or lower than a predetermined threshold in black image data, it is possible to reduce random noise while maintaining fixed pattern noise such as black floating and white flaws. Are listed. In Patent Document 2, random noise is reduced while maintaining fixed pattern noise such as streaky black floats and line flaws by performing smoothing processing in a one-dimensional row or column direction of a pixel arrangement of a black image. Is described.
JP-A-2005-340928 JP 2007-28026 A

  However, the above-described prior art has not been sufficient to perform random black removal processing by removing random noise while leaving fixed pattern noise from a black image. For example, since the technique disclosed in Patent Document 1 is a noise classification method based on a signal level threshold, there is a problem in that streaky black floats with a small signal level are smoothed together with random noise. Further, in the technique described in Patent Document 2, since the correlation in the one-dimensional smoothing process direction becomes strong when the random noise is large even in a region without streaky black floats or line flaws, the random noise is increased. There was a problem of streaks remaining.

  The present invention has been made for the purpose of solving at least one of the problems of the prior art. That is, an object of the present invention is to provide an imaging apparatus, a control method thereof, and a program for improving the result of blacking processing by generating a black image from which random noise is removed while leaving noise inherent to the imaging element. To do.

  The object is to remove the inherent noise of the image sensor by performing a blacking process that includes an image sensor and subtracts a black image acquired in a state where the image sensor is shielded from an image obtained by capturing the subject image with the image sensor. An imaging apparatus capable of acquiring a captured image, wherein the black image is divided into a plurality of divided images, and each of the divided images is detected by detecting presence or absence of noise extending in one direction. First detection means for detecting the presence or absence of noise, second detection means for detecting the extending direction of the inherent noise for each of the divided images for which inherent noise has been detected by the first detection means, and For each of the divided images in which the inherent noise is not detected, isotropic two-dimensional smoothed image processing is performed, and for the divided image in which the inherent noise is detected, the inherent image is processed. A black image comprising divided images after the image processing by the image processing means, the image processing means performing an anisotropic two-dimensional smoothed image processing that does not smooth the inherent noise based on the direction in which the noise extends Is achieved by the imaging apparatus according to the present invention, which is used for the blacking process.

  In addition, the above object is provided with an image pickup device, and the inherent noise of the image pickup device is reduced by a blacking process that subtracts a black image acquired in a state where the image pickup device is shielded from an image obtained by capturing the subject image with the image pickup device. An image pickup apparatus control method capable of acquiring a removed picked-up image, the step of dividing the black image into a plurality of divided images, and detecting the presence or absence of noise extending in one direction for each of the divided images A first detection step of detecting the presence or absence of the inherent noise, and a second detection step of detecting the extending direction of the inherent noise for each of the divided images in which the inherent noise is detected by the first detection step; For each of the divided images, an isotropic two-dimensional smoothed image process is performed on the divided images in which the inherent noise is not detected, and the divided images in which the inherent noise is detected are processed. And an image processing step that performs anisotropic two-dimensional smoothed image processing that does not smooth the inherent noise based on the extending direction of the inherent noise, and a divided image after image processing by the image processing step It is also achieved by a method for controlling an imaging apparatus according to the present invention, wherein a black image comprising:

  According to the present invention, it is possible to improve the result of the blacking process by generating a black image from which random noise is removed while leaving noise inherent to the image sensor.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, the embodiment of the present invention shows the most preferable mode of the invention, and does not limit the scope of the invention.

  FIG. 1 is a block diagram showing a schematic configuration of an imaging apparatus 1 according to the present invention. As shown in FIG. 1, the imaging apparatus 1 photoelectrically converts light imaged through an optical system 101 and a shutter 102 by an imaging element 103 to obtain image data obtained by imaging a subject image. Image data acquired by photoelectric conversion is digitized through a pre-processing circuit 104 including a CDS (Correlated Double Sampling) circuit and a non-linear amplification circuit for removing output noise, and an A / D converter 105. The digitized image data is temporarily stored in the memory 107 via the memory controller 106. The image data stored in the memory 107 is recorded on the recording medium 109 after being subjected to various image processing and conversion into a predetermined image format such as JPEG (Joint Photographic Experts Group) by the image processing unit 108. Note that various image processing in the image processing unit 108 includes blacking processing for subtracting black image data captured in a light-shielded state by the shutter 102 from image data obtained by capturing a subject image, and noise for reducing random noise in the image data. Reduction processing is also included.

  The operation display unit 110 is a liquid crystal panel that displays a captured image obtained by capturing a subject image and status information of the imaging apparatus 1. The first switch 111 is a switch that receives an instruction for performing an imaging standby operation. The second switch 112 is a switch that accepts an instruction to perform shooting during imaging standby according to an instruction from the first switch 111.

  The system control unit 113 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown), and centrally controls the operation of the imaging apparatus 1. Specifically, the system control unit 113 expands program data stored in a ROM or the like in a work area of the RAM, and performs overall control of each unit in cooperation with the expanded program data and the CPU.

  The shutter control circuit 114 is a circuit that generates a control signal related to driving of the shutter 102 under the control of the system control unit 113. The temperature sensor 115 is disposed in the vicinity of the image sensor 103, measures the temperature of the image sensor 103, and outputs a temperature detection signal indicating the measured value to the system control unit 113. The main switch 116 is a switch for instructing power-on of the imaging apparatus 1. Note that the configuration of the imaging device 1 is not limited to that described above. For example, the imaging apparatus 1 may include a setting switch for setting sensitivity at the time of imaging in the imaging element 103 and setting an exposure time, a strobe for irradiating the subject with auxiliary light, and the like.

  Next, an outline of the operation of still image capturing with blackening processing performed under the control of the system control unit 113 will be described. First, the system control unit 113 performs an imaging standby operation such as AF (Auto Focus) by operating the first switch 111, and starts an imaging operation of the subject by operating the second switch 112.

  With the start of the imaging operation, the system control unit 113 reads from the ROM table data (details will be described later) in which black image imaging conditions, which are imaging conditions for performing blacking processing, are set. Next, the system control unit 113 determines whether the sensitivity, exposure time, and temperature of the image sensor 103 measured by the temperature sensor 115 set during the imaging operation meet the conditions for performing blacking processing set in the table data. Determine whether. In this determination, when the condition for performing the black drawing process is satisfied, the imaging apparatus 1 performs still image pickup with the black drawing process.

  The system control unit 113 causes the image sensor 103 to capture a subject image by starting still image capturing with blackening processing. Next, the system control unit 113 uses the same image sensor 103 that has captured the subject image, and closes the shutter 102 to put it in a light-shielding state, so that the same imaging settings (sensitivity setting, exposure time, etc.) as the subject image is captured. To capture a black image. Next, the system control unit 113 controls the image processing unit 108 to perform noise reduction processing on the captured black image as necessary by detecting the condition of the captured image and a black float in the shape of the captured black image. A captured image is acquired by performing blacking processing for subtracting the black image from the image.

  In the following description, the operation of the imaging apparatus 1 executed under the control of the system control unit 113 will be described in detail with reference to the flowchart illustrated in FIG. As shown in FIG. 2, in S201, the system control unit 113 detects the state of the main switch 116 that powers on the system, and if it is ON, the process proceeds to S202. In S202, the system control unit 113 checks the remaining capacity of the recording medium 109. If the remaining capacity is 0, the process proceeds to S203, and if the remaining capacity is not 0, the process proceeds to S204. In S203, the system control unit 113 warns that the remaining capacity of the recording medium 109 is 0, and returns to S201. This warning may be displayed on the operation display unit 110, or a warning sound may be output from a sound output unit (not shown) such as a speaker, or both.

  In S204, the system control unit 113 checks the state of the first switch 111. If it is ON, the process proceeds to S206, and if it is not ON, the process proceeds to S205. Note that the instruction received by the first switch 111 by ON / OFF or the like is the presence or absence of an imaging standby operation such as AF or AE. In S205, the system control unit 113 checks the state of the main switch 116. If it is ON, the process proceeds to S204, and if it is not ON, the process proceeds to S201. In S206 and S207, the system control unit 113 sequentially executes AE processing and AF processing.

  In S208, the system control unit 113 checks the state of the second switch 112, and if it is ON, the process proceeds to S210, and if it is not ON, the process proceeds to S209. Note that the instruction received by the second switch 112 being turned ON / OFF or the like is an imaging instruction during imaging standby after the first switch 111 is operated. In S209, the system control unit 113 checks the state of the first switch 111. If it is ON, the process returns to S208, and if it is not ON, the process returns to S204. In S210, the system control unit 113 performs a shooting operation according to a flowchart of a shooting process to be described later. In S211, the system control unit 113 checks the remaining capacity of the recording medium 109. If the remaining capacity is 0, the process proceeds to S203, and if the remaining capacity is not 0, the process proceeds to S212. Note that the remaining capacity check in S202 and S211 may be a remaining capacity check based on a predetermined threshold necessary to record one image, and whether or not the remaining capacity is zero. It is not limited to the survey. In S212, the state of the second switch 112 is checked. If it is not ON, the process proceeds to S209.

  Here, the details of the photographing process (S210) will be described with reference to the flowchart illustrated in FIG. As shown in FIG. 3, in S301, the system control unit 113 performs a charge clear operation of the image sensor 103, and starts charge accumulation in S302. After the charge accumulation, the system control unit 113 opens the shutter 102 in S303 and starts exposure of the image sensor 103 (S304). The exposure of the image sensor 103 in S304 is exposure for obtaining a captured image (main image) obtained by capturing a subject image. The subject image formed on the imaging surface of the image sensor 103 is photoelectrically converted and charges are accumulated in the image sensor 103. Thereafter, the system control unit 113 waits for the exposure time set by the AE process and closes the shutter 102 in S305. In S <b> 306, the system control unit 113 finishes the charge accumulation of the image sensor 103, reads the image signal (captured image data) of the image sensor 103 in S <b> 307, performs A / D conversion, and stores it in the memory 107.

  In step S308, the system control unit 113 refers to the black image capturing conditions set in advance in the ROM or the like based on the imaging conditions such as the sensitivity at the time of capturing the subject image, the exposure time, and the image sensor temperature, and captures the subject image. It is determined whether or not the current imaging condition is applicable to the black image imaging condition. In S308, the system control unit 113 advances the process to S309 if the imaging condition at the time of subject increase imaging applies to the black image imaging condition, and advances to S317 if not.

  Here, preset black image capturing conditions will be described with reference to FIG. As shown in FIG. 4A, the black image capturing condition is table data in which an imaging condition (sensitivity, exposure time, temperature) for performing blacking processing using a black image is set. According to this black image capturing condition, for example, in the case of the imaging condition of exposure time to 1 sec and imaging sensitivity ISO 1600, blacking processing by black image capturing is performed when the temperature of the image sensor 103 is 20 ° C. or higher. Become.

  In S309, the system control unit 113 performs a charge clear operation of the image sensor 103, and starts charge accumulation in S310. In step S311, the system control unit 113 starts exposure in a light-shielded state with the shutter 102 closed to capture a black image. Thereafter, the system control unit 113 waits for the same exposure time as when the subject image is captured in S304, terminates the charge accumulation of the image sensor 103 in S312, and reads the image signal (black image data) of the image sensor 103 in S313. . In S314, the system control unit 113 performs noise reduction processing as necessary on the read black image data in accordance with a black image processing flowchart described later.

  In S315, the system control unit 113 performs blacking processing for subtracting the black image data from the captured image data using the captured image data stored in the memory 107 and the black image data processed in S314. In the black subtraction process, the black image data subjected to the noise reduction process in S314 is subtracted from the captured image data at the same pixel position, and an image process such as adding a uniform value as an OB (optical black) value is performed. Is called. The imaging device 1 can acquire a captured image from which the inherent noise of the imaging element 103 is removed by this blacking process.

  In step S316, the system control unit 113 performs image processing such as white balance adjustment on the captured image data read in step S307 and the captured image data after the blacking process, and generates an appropriate output image signal. . In S317, the system control unit 113 performs image conversion of the output image signal to the JPEG format or the like by the image processing unit 108, and then transfers and records the output image signal to the recording medium 109 in S318.

  Here, details of the black image processing (S314) will be described with reference to the flowchart illustrated in FIG. The purpose of the black image processing is to reduce the random noise of the black image used for the black drawing process in order to avoid the adverse effect of the image quality degradation due to the increase of random noise during the black drawing process. Here, if streaky black floats occur in the black image, black lines will be used in the black drawing process unless the streaky black floats are left in the black image after noise reduction processing to reduce random noise. Care must be taken because it is impossible to perform correction for the black floating in the shape.

  As shown in FIG. 5, in S501, the system control unit 113 refers to the black image unprocessed conditions set in advance in the ROM or the like for the imaging conditions such as the sensitivity of the captured image, the exposure time, and the imaging element temperature. It is determined whether or not the imaging condition is a black image unprocessed condition. In S501, the system control unit 113 returns without performing any processing (noise reduction process) if the imaging condition matches the black image unprocessed condition, and if the imaging condition does not match the black image unprocessed condition, the process proceeds to S502. Processing proceeds.

  Here, the black image unprocessed conditions set in advance will be described with reference to FIG. As shown in FIG. 4B, the black image unprocessed condition is table data in which imaging conditions (sensitivity, exposure time, temperature) in which the black image noise reduction process is to be unprocessed are set. Although this black image unprocessed condition depends on the characteristics of the imaging device, it is generally a more severe condition such as a higher temperature than the black image imaging condition illustrated in FIG. With this black image unprocessed condition, for example, in the case of an image capture condition with an exposure time of 1 sec and an imaging sensitivity of ISO 1600, the noise reduction process of the black image is unprocessed when the temperature of the image sensor 103 is 50 ° C. or higher. .

  Here, a black image unprocessed condition will be described by taking as an example a case where noise reduction processing is not performed on a black image. For example, in a spot-flaw correction circuit that corrects a spot or the like based on preset scratch information, blacking out is performed under an imaging condition in which the number of spots exceeds the upper limit due to the limitation of the memory capacity for storing the scratch information. It is necessary to correct the flaws by processing. In this case, it is necessary to leave spots in the black image after noise reduction processing to reduce random noise, but random noise also occurs under imaging conditions (for example, at high temperatures) such as when many spots are generated. It becomes. Therefore, under the above-described imaging conditions, it is difficult to reduce only random noise as distinguished from point marks. In such a case, the black image unprocessed condition is set so that the black drawing process is performed while the noise reduction process of the black image is not processed. That is, for the black image unprocessed condition, an imaging condition for obtaining a captured image in which it is difficult to distinguish between noise unique to the imaging element and random noise is set in advance.

  In step S <b> 502, the system control unit 113 sets a block for dividing the captured image on the imaging surface on the image sensor 103 into a plurality of blocks (divided images). Specifically, as shown in FIG. 6, on the imaging surface on the imaging device 103, an opening area 103 a that is a light receiving area capable of receiving light incident from the optical system 101 and light incident from the optical system 101. There is an OB region 103b which is a light-shielding region that does not hit. Note that there is a structure in which the image sensor 103 does not have a photosensor or the like in the OB region 103b. On the imaging surface of the image sensor 103, the opening area 103a and the OB area 103b are distinguished, the OB area 103b is excluded from the area to be divided into blocks, and the captured image in the area corresponding to the opening area 103a is divided into blocks. . In addition, the image sensor 103 considers that the image to be divided by the block is a black image and the continuity of the black float occurrence state, and based on the presence or absence of the photosensor, the photosensor installation area 103c is divided into blocks. It may be a target area. Further, the block described above may be a rectangular area obtained by dividing the entire area to be divided by, for example, an n × m grid.

  In the black image, streak-like black floating detection and noise reduction processing (S503 to S507) for reducing random noise, which will be described later, are performed for each of a plurality of blocks (divided images) set in S502. This is to reduce random noise while leaving streak-like black float by processing for each block even when the occurrence status and level of streaky black float differ at the top and bottom of the screen. It is.

  In step S503, the system control unit 113 performs predetermined signal processing for a plurality of different directions in each block obtained by dividing the black image. In the present embodiment, high frequency components of noise are compared in two directions of the black image in the vertical direction and the horizontal direction. By this signal processing, the system control unit 113 can detect streaky black floating in the block, that is, the presence or absence of noise extending in one direction (first detection means). This is because the white noise component due to random noise has no direction dependency, but when streaky black floating occurs, the correlation is strong in that direction, and the image signal is in two directions, the horizontal direction and the vertical direction. This is because a difference occurs in the components. By such signal processing, the system control unit 113 can appropriately detect the occurrence of streaky black floating from random noise even at a minute signal level.

  Specifically, in S503, the system control unit 113 performs a two-dimensional low-pass filter process on the black image, obtains an image obtained by extracting a high-frequency component of the image signal component by taking a difference from the original black image. Further, the system control unit 113 performs a one-dimensional low-pass filter process on the black image in the vertical direction and the horizontal direction, obtains a difference image from the two images obtained with absolute values, and compares the high-frequency components of the image signal components in the two directions. To do.

  In step S504, the system control unit 113 obtains a block integration value for each block set in step S502 for the difference image obtained in step S503, and determines whether or not a streak-like black float occurs and the generation direction (extension direction). To detect. In S504, if the absolute value of the block integral value is smaller than a predetermined value, it is determined that no streaky black float has occurred, and if it is larger than the predetermined value, a streaky black float has occurred. Determined and detected. Here, if the difference image is obtained by subtracting the image that has been subjected to the one-dimensional low-pass filter processing in the horizontal direction from the image that has been subjected to the one-dimensional low-pass filter processing in the horizontal direction, and the absolute value of the block integral value is greater than a predetermined value and positive, The direction of occurrence of streaky black float is detected as the vertical direction. Further, when the absolute value of the block integral value is larger than a predetermined value and negative, the generation direction of streaky black float is detected as the horizontal direction. That is, the system control unit 113 detects the extending direction of the streaky black float that is the inherent noise (second detection means).

  In S505, the system control unit 113 determines whether or not the occurrence of streaky black float is detected in S504. If it is detected, the process proceeds to S506, and if not, the process proceeds to S507.

  In step S506, the system control unit 113 performs one-dimensional smoothing processing in the direction in which the streaky black float detected in step S504 occurs, that is, performs anisotropic two-dimensional smoothing processing. This makes it possible to reduce random noise while leaving streaky black floating in the black image. In step S507, the system control unit 113 performs isotropic two-dimensional smoothing processing that performs smoothing processing equivalently in any direction on the imaging surface because no streaky black float is detected. As a result, random noise can be reduced without leaving streaks. The smoothing process described above is performed by a low-pass filter process, an averaging process, a median process, or the like.

  As described above, the system control unit 113 performs isotropic two-dimensional smoothed image processing on the divided images in which the inherent noise is not detected by performing the above-described black image processing. Further, the system control unit 113 performs anisotropic two-dimensional smoothed image processing that does not smooth the inherent noise based on the extending direction of the inherent noise for the divided image in which the inherent noise is detected, and serves as an image processing unit. Function. Therefore, the imaging apparatus 1 can use a black image composed of divided images after image processing, that is, a black image from which random noise has been removed while leaving noise inherent to the image sensor 113, for blacking processing. It is possible to improve the results.

  Note that the description in the above-described embodiment shows an example, and the present invention is not limited to this. The configuration and operation in the embodiment described above can be changed as appropriate.

(Other embodiments)
The above-described embodiment can also be realized in software by a computer of a system or apparatus (or CPU, MPU, etc.). Therefore, the computer program itself supplied to the computer in order to implement the above-described embodiment by the computer also realizes the present invention. That is, the computer program itself for realizing the functions of the above-described embodiments is also one aspect of the present invention.

  The computer program for realizing the above-described embodiment may be in any form as long as it can be read by a computer. For example, it can be composed of object code, a program executed by an interpreter, script data supplied to the OS, but is not limited thereto. A computer program for realizing the above-described embodiment is supplied to a computer via a storage medium or wired / wireless communication. Examples of the storage medium for supplying the program include a magnetic storage medium such as a flexible disk, a hard disk, and a magnetic tape, an optical / magneto-optical storage medium such as an MO, CD, and DVD, and a nonvolatile semiconductor memory.

  As a computer program supply method using wired / wireless communication, there is a method of using a server on a computer network. In this case, a data file (program file) that can be a computer program forming the present invention is stored in the server. The program file may be an executable format or a source code. The program file is supplied by downloading to a client computer that has accessed the server. In this case, the program file can be divided into a plurality of segment files, and the segment files can be distributed and arranged on different servers. That is, a server apparatus that provides a client computer with a program file for realizing the above-described embodiment is also one aspect of the present invention.

  In addition, a storage medium in which the computer program for realizing the above-described embodiment is encrypted and distributed is distributed, and key information for decrypting is supplied to a user who satisfies a predetermined condition, and the user's computer Installation may be allowed. The key information can be supplied by being downloaded from a homepage via the Internet, for example. Further, the computer program for realizing the above-described embodiment may use an OS function already running on the computer. Further, a part of the computer program for realizing the above-described embodiment may be configured by firmware such as an expansion board attached to the computer, or may be executed by a CPU provided in the expansion board. Good.

It is a block diagram which shows schematic structure of the imaging device which concerns on this invention. It is a flowchart which shows operation | movement of an imaging device. It is a flowchart which shows the imaging | photography process of an imaging device. (A) is a conceptual diagram which illustrates the outline of black image imaging conditions, (b) is a conceptual diagram which shows the outline of black image unprocessed conditions. It is a flowchart which shows the black image process of an imaging device. It is a conceptual diagram which shows the outline | summary which divides | segments the imaging surface of an image pick-up element into a some area | region.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image pick-up apparatus 101 Optical system 102 Shutter 103 Image pick-up element 104 Preprocessing circuit 105 A / D converter 106 Memory controller 107 Memory 108 Image processing part 109 Recording medium 110 Operation display part 111 1st switch 112 2nd switch 113 System control part 114 Shutter control circuit 115 Temperature sensor 116 Main switch

Claims (7)

Obtaining a captured image from which the inherent noise of the image sensor has been removed by subtracting a black image acquired with the image sensor being shielded from an image obtained by capturing an image of a subject with the image sensor A possible imaging device,
Dividing means for dividing the black image into a plurality of divided images;
First detection means for detecting the presence or absence of the intrinsic noise by detecting the presence or absence of noise extending in one direction for each of the divided images;
Second detection means for detecting the extending direction of the inherent noise for each of the divided images in which the inherent noise is detected by the first detection means;
For each of the divided images, an isotropic two-dimensional smoothed image process is performed for the divided image in which the inherent noise is not detected, and the extending direction of the inherent noise is performed for the divided image in which the inherent noise is detected. Image processing means for performing anisotropic two-dimensional smoothed image processing that does not smooth the inherent noise based on
An image pickup apparatus, wherein a black image composed of divided images after image processing by the image processing means is used for the blacking processing.   The first detection means detects the presence or absence of noise extending in the one direction for each of the divided images based on a difference between a vertical image signal component and a horizontal image signal component in the divided image. The imaging apparatus according to claim 1.   The imaging apparatus according to claim 2, wherein the vertical image signal component and the horizontal image signal component are high-frequency components in the image signal of the divided image. The imaging element has a light receiving region for receiving the subject image and a light-shielded light-shielding region during imaging of the subject image,
The imaging device according to any one of claims 1 to 3, wherein the dividing unit divides a black image corresponding to the light receiving region in the black image into a plurality of images.   5. The image processing unit according to claim 1, wherein the image processing unit performs one-dimensional smoothed image processing in the extending direction detected by the second detection unit for the divided image in which the inherent noise is detected. The imaging device according to any one of the above. Obtaining a captured image from which the inherent noise of the image sensor has been removed by subtracting a black image acquired with the image sensor being shielded from an image obtained by capturing an image of a subject with the image sensor A control method for a possible imaging device,
A dividing step of dividing the black image into a plurality of divided images;
A first detection step of detecting the presence or absence of the inherent noise by detecting the presence or absence of noise extending in one direction for each of the divided images;
A second detection step of detecting the extending direction of the inherent noise for each of the divided images in which the inherent noise is detected by the first detection step;
For each of the divided images, an isotropic two-dimensional smoothed image process is performed for the divided image in which the inherent noise is not detected, and the extending direction of the inherent noise is performed for the divided image in which the inherent noise is detected. An anisotropic two-dimensional smoothed image processing that does not smooth the intrinsic noise based on
A method for controlling an imaging apparatus, wherein a black image formed of divided images after image processing in the image processing step is used for the blacking processing.   The program for making a computer perform each process of the control method of the imaging device of Claim 6.

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