JP2016082390A - Signal processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a signal processing unit capable of detecting generation of fog etc. even under low illumination circumstances like night to improve the visibility of images by correcting a brightness signal.SOLUTION: The signal processing unit includes: a filter; a determination part; and a correction section. The filter extracts a high frequency component of a brightness signal and a high frequency component of an infra-red signal. The determination part determines whether the high frequency component of the extracted infra-red signal is larger than the high frequency component of the extracted brightness signal. The correction section corrects the brightness signal based on the determination result.SELECTED DRAWING: Figure 4

Description

  The present technology relates to a signal processing device, an imaging device, and a signal processing method. Specifically, the present invention relates to an imaging device used for a monitoring camera, a signal processing device in the imaging device, a processing method in these, and a program for causing a computer to execute the method.

  2. Description of the Related Art Conventionally, surveillance cameras including an image sensor that outputs an image signal corresponding to visible light and infrared light and a signal processing device that processes the image signal are used. When such a surveillance camera is used in a state where fog or smoke is generated, short-wavelength light of visible light is irregularly reflected by fog or the like, and the signal level of the image signal in the dark part of the subject increases and the contrast decreases. . For this reason, the image of the surveillance camera is an image with reduced visibility. In order to prevent this, there has been proposed an imaging apparatus that determines whether or not fog or the like is generated, and performs processing for increasing the contrast of an image when these are generated. For example, when an image signal corresponding to visible light and an image signal corresponding to infrared light are acquired from the image sensor, and the signal level in the dark part of the image signal corresponding to visible light falls below a predetermined level, fog And so on. In this case, for the image signals corresponding to visible light and infrared light, an image signal having a lower signal level of the image signal in the dark part is selected and the contrast of the image signal is enhanced. Thus, a system for outputting a high-contrast image signal has been proposed (see, for example, Patent Document 1).

JP 2012-054904 A

  In the above-described conventional technology, generation of fog or the like is detected by using an image signal corresponding to infrared light that is difficult to scatter compared to visible light because of its long wavelength. However, since the comparison is performed based on the signal level of the image signal in the dark part, it is difficult to detect the occurrence of fog or the like in photographing in a low-luminance environment, and there is a problem in that the reduction in contrast cannot be compensated.

  The present technology has been devised in view of such a situation, and an object thereof is to detect the occurrence of fog or the like even in a low-light environment such as nighttime and improve the visibility of an image.

  The present technology has been made to solve the above-described problems. The first aspect of the present technology is a filter that extracts a high-frequency component of a luminance signal and a high-frequency component of an infrared light signal, and the above-described extraction. A determination unit that determines whether or not the extracted high-frequency component of the infrared light signal is larger than the high-frequency component of the luminance signal; and a correction unit that corrects the luminance signal based on the determination result. A signal processing apparatus. Thereby, when the high frequency component of the infrared light signal is larger than the high frequency component of the luminance signal, the luminance signal is corrected.

  Further, in this first aspect, when the correction unit determines that the extracted high frequency component of the infrared light signal is larger than the high frequency component of the extracted luminance signal in the determination unit. Alternatively, the luminance signal having a signal level lower than a predetermined signal level may be attenuated. Thus, when it is determined that the high frequency component of the infrared light signal is larger than the high frequency component of the luminance signal, the luminance signal having a signal level lower than a predetermined signal level is attenuated.

  Further, in this first aspect, when the correction unit determines that the extracted high frequency component of the infrared light signal is larger than the high frequency component of the extracted luminance signal in the determination unit. In addition, the extracted high frequency component of the infrared light signal may be mixed with the luminance signal based on a predetermined ratio. Accordingly, when it is determined that the high frequency component of the infrared light signal is larger than the high frequency component of the luminance signal, the high frequency component of the infrared light signal is mixed with the luminance signal based on a predetermined ratio.

  In the first aspect, the determination unit makes a determination by comparing an average value of the high-frequency components of the extracted luminance signal with an average value of the high-frequency components of the extracted infrared light signal. May be. This brings about the effect that the average value of the high frequency component of the luminance signal and the average value of the high frequency component of the infrared light signal are compared and determined.

  In the first aspect, the determination unit compares the root mean square value of the extracted high frequency component of the luminance signal with the root mean square value of the extracted high frequency component of the infrared light signal. You may judge. This brings about the effect of making a determination by comparing the root mean square value of the high frequency component of the luminance signal with the root mean square value of the high frequency component of the infrared light signal.

  In addition, the second aspect of the present technology provides an imaging device that outputs a visible light signal and an infrared light signal, a generation unit that generates a luminance signal from the output visible light signal, and the generated luminance. A filter that extracts a high-frequency component of the signal and a high-frequency component of the output infrared light signal, and a higher-frequency component of the extracted infrared light signal than a high-frequency component of the extracted luminance signal. The imaging apparatus includes a determination unit that determines whether the signal is large and a correction unit that corrects the luminance signal based on a result of the determination. Thereby, when the high frequency component of the infrared light signal is larger than the high frequency component of the luminance signal, the luminance signal is corrected.

  The third aspect of the present technology provides an extraction procedure for extracting a high-frequency component of a luminance signal and a high-frequency component of an infrared light signal, and the infrared extracted from the extracted high-frequency component of the luminance signal. The signal processing method includes a determination procedure for determining whether or not a high-frequency component of an optical signal is larger, and a correction procedure for correcting the luminance signal based on the result of the determination. Thereby, when the high frequency component of the infrared light signal is larger than the high frequency component of the luminance signal, the luminance signal is corrected.

  According to the present technology, it is possible to achieve an excellent effect of improving visibility by detecting occurrence of fog or the like and correcting an image signal even in a low-light environment such as nighttime. Note that the effects described here are not necessarily limited, and may be any of the effects described in the present disclosure.

It is a figure showing an example of composition of an imaging device in an embodiment of this art. It is a figure showing an example of composition of image sensor 200 in an embodiment of this art. It is a figure showing an example of composition of signal processor 300 in an embodiment of this art. It is a figure showing an example of composition of image processing part 360 in a 1st embodiment of this art. It is a figure showing an example of composition of signal conversion part 361 in a 1st embodiment of this art. It is a figure showing an example of composition of HPF362 in a 1st embodiment of this art. It is a figure showing the amendment method in a 1st embodiment of this art. It is a figure showing an example of a signal processing procedure in a 1st embodiment of this art. It is a figure showing an example of composition of image processing part 360 in a 2nd embodiment of this art.

Hereinafter, modes for carrying out the present technology (hereinafter referred to as embodiments) will be described. The description will be made in the following order.
1. First Embodiment (Example in the case of correcting by increasing the contrast of a visible light signal)
2. Second embodiment (example in which high-frequency component of infrared light signal is added to visible light signal for correction)

<1. First Embodiment>
[Configuration of imaging device]
FIG. 1 is a diagram illustrating a configuration example of an imaging device according to an embodiment of the present technology. The imaging device 10 in the figure includes a lens 100, an imaging element 200, a signal processing device 300, an image signal output unit 400, and an infrared light irradiation unit 500.

  The lens 100 optically forms a subject on the image sensor 200. The image sensor 200 converts an optical image formed by the lens 100 into an image signal and outputs the image signal. The imaging device 200 is configured by two-dimensionally arranging pixels that generate image signals on a surface on which an optical image is formed. This pixel includes a pixel (R pixel) that outputs an image signal corresponding to red light, a pixel (G pixel) that outputs an image signal corresponding to green light, and a pixel (B pixel) that outputs an image signal corresponding to blue light. ) Is included. This pixel further includes a pixel (IR pixel) that outputs an image signal corresponding to infrared light. Hereinafter, an image signal corresponding to red light, an image signal corresponding to green light, an image signal corresponding to blue light, and an image signal corresponding to infrared light are referred to as an R signal, a G signal, a B signal, and an IR signal, respectively. Note that the image sensor 200 is controlled by the signal processing device 300.

  The signal processing device 300 processes an image signal. The signal processing device 300 generates a luminance signal and a color difference signal from image signals (R signal, G signal, and B signal), and performs various processes on these signals and IR signals. Thereafter, the processed image signal is output. The signal processing device 300 also performs overall control of the imaging device 10.

  The image signal output unit 400 outputs the image signal processed by the signal processing device 300 to the outside of the imaging device 10. The image signal output unit 400 converts and outputs an image signal so as to conform to the standard of the signal line interface to which the imaging device 10 is connected.

  The infrared light irradiation unit 500 irradiates the subject with infrared light. The infrared light irradiation unit 500 is controlled by the signal processing device 300.

[Configuration of image sensor]
FIG. 2 is a diagram illustrating a configuration example of the image sensor 200 according to the embodiment of the present technology. The image sensor 200 is configured by arranging pixels 201 in a two-dimensional lattice pattern on a screen. Note that the symbol written in the pixel 201 represents the type of the pixel 201. Pixels in which R, G, B, and IR are described represent an R pixel, a G pixel, a B pixel, and an IR pixel, respectively. These pixels are arranged on the screen based on a certain rule.

  In the figure, a represents an example of an arrangement in which R pixels, G pixels, and B pixels are arranged in a Bayer arrangement, and one of the two G pixels is replaced with an IR pixel. Further, b in the figure represents an example in which IR pixels are arranged instead of G pixels in the Bayer array, and the other pixels are arranged so that the ratio of G pixels to R pixels and B pixels is 2. Is. More IR pixels are arranged than the image sensor represented by a in the figure, and the resolution for infrared light can be increased. Note that these display only a part of the screen, and such a pixel arrangement is repeated on the entire screen to form the screen of the image sensor 200.

[Configuration of signal processing apparatus]
FIG. 3 is a diagram illustrating a configuration example of the signal processing device 300 according to the embodiment of the present technology. The signal processing apparatus 300 includes an image sensor interface 310, a processor 320, an output interface 330, a RAM 340, a ROM 350, an image processing unit 360, an image compression unit 370, and a bus 301.

  The image sensor interface 310 exchanges data with the image sensor 200 and captures image signals. This image signal includes an R signal, a G signal, a B signal, and an IR signal.

  The processor 320 controls the entire signal processing apparatus 300. The processor 320 also controls the image sensor 200 and the infrared light irradiation unit 500 (not shown).

  The RAM 340 temporarily stores data. The RAM 340 has an image memory for storing image signals and a work memory for storing work data created by the processor 320. The ROM 350 is a memory that stores the firmware of the processor 320.

  The image processing unit 360 performs various types of signal processing on the image signals (R signal, G signal, B signal, and IR signal). Details of the image processing unit 360 will be described later.

  The image compression unit 370 encodes and compresses the image signal processed by the image processing unit 360 and generates a bit stream that is a bit string of image data in a moving image. Note that a moving picture experts group (MPEG) format can be used as a method for encoding image data.

  The output interface 330 outputs the bit stream generated by the image compression unit 370 to the image signal output unit 400. The bus 301 connects each part in the signal processing device 300 to each other.

[Configuration of image processing unit]
FIG. 4 is a diagram illustrating a configuration example of the image processing unit 360 according to the first embodiment of the present technology. The image processing unit 360 includes a signal conversion unit 361, a high pass filter (HPF) 362, a determination unit 363, and a correction unit 364. The HPF 362 is an example of a filter described in the claims.

  The signal conversion unit 361 converts the R signal, the G signal, and the B signal into a luminance signal (Y signal) and a color difference signal (Cb and Cr signal). The color difference signal Cb is a signal based on the difference between the B signal and the luminance signal, and the color difference signal Cr is a signal based on the difference between the R signal and the luminance signal. The signal conversion unit 361 also performs processing such as demosaic processing.

  The HPF 362 extracts the high frequency component by removing the low frequency component of the Y signal and the IR signal and passing the high frequency component. The high frequency components of the extracted Y signal and IR signal are referred to as Y_H signal and IR_H signal, respectively.

  The determination unit 363 compares the high frequency component Y_H signal of the Y signal output from the HPF 362 with the high frequency component IR_H signal of the IR signal, and the high frequency component IR_H signal of the IR signal is larger than the high frequency component Y_H signal of the Y signal. Whether or not. The correction unit 364 corrects the Y signal based on the determination result by the determination unit 363 and generates a Y ′ signal that is a corrected luminance signal. Details of the operations of the determination unit 363 and the correction unit 364 will be described later.

[Configuration of signal converter]
FIG. 5 is a diagram illustrating a configuration example of the signal conversion unit 361 according to the first embodiment of the present technology. The signal conversion unit 361 includes a dark current variation correction unit 367, a demosaic unit 368, and a YC conversion unit 369.

  The dark current variation correction unit 367 corrects dark current variation in each pixel of the image sensor 200. This dark current variation correction can be performed, for example, by subtracting the dark current value of each pixel acquired in advance from the image signal. The dark current variation correction unit 367 may correct pixel defects. This is because a pixel defect can be regarded as a state in which the variation in dark current is large, and can be corrected by a method similar to the dark current variation correction.

  The demosaic unit 368 performs demosaic processing. This demosaic process is to interpolate a deficient image signal with respect to a monochromatic image signal output from the image sensor 200. By this demosaic processing, the image signal per pixel increases to four signals of R signal, G signal, B signal and IR signal. A known method can be used as this demosaic process. For example, when the R signal is interpolated in the interpolation target pixel, a method in which the average value of the R signals in the R pixels around the interpolation target pixel is used as the R signal of the interpolation target pixel can be used.

The YC conversion unit 369 converts the R signal, the G signal, and the B signal into a Y signal, a Cb signal, and a Cr signal. This conversion can be performed based on the following equation.
Y = 0.299 × R + 0.587 × G + 0.114 × B
Cb = −0.169 × R−0.331 × G + 0.500 × B
Cr = 0.500 × R−0.419 × G−0.081 × B
However, R, G, and B represent R signal, G signal, and B signal, respectively. The YC conversion unit 369 is an example of a generation unit described in the claims.

  Note that the processing in the signal conversion unit 361 is not limited to the processing described above, and processing other than these, for example, processing such as noise reduction, may be added.

ただし、Ｙ＿ＨおよびＲＩ＿Ｈは、それぞれＹ信号の高周波成分およびＲＩ信号の高周波成分を表す。ＹｉおよびＲＩｉは、入力されたＹ信号およびＲＩ信号を表す。Ｋｉは、係数である。また、添え字ｉは、Ｙ信号、ＲＩ信号および係数Ｋを識別するものである。このように係数Ｋを乗算したＹ信号およびＲＩ信号を加算して演算を行う。この演算を画素ごとに行う。 [Configuration of HPF]
FIG. 6 is a diagram illustrating a configuration example of the HPF 362 according to the first embodiment of the present technology. The HPF 362 passes the high frequency component of the input image signal by the calculation of the image signal and removes the low frequency component. This calculation is shown in the following equation, and is performed for the Y signal and the RI signal.

However, Y_H and RI_H represent the high frequency component of the Y signal and the high frequency component of the RI signal, respectively. Yi and RIi represent the input Y signal and RI signal. Ki is a coefficient. The subscript i identifies the Y signal, the RI signal, and the coefficient K. The calculation is performed by adding the Y signal and the RI signal multiplied by the coefficient K in this way. This calculation is performed for each pixel.

  In the figure, “a” illustrates the state of calculation, taking the case of a luminance signal as an example. The figure shows a case where the luminance signals Y11 to Y55 are calculated. K11 to K55 are coefficients. In the figure, b represents the arrangement of the pixels corresponding to Y11 to Y55, and represents the case where the pixel corresponding to Y33 is calculated as the pixel of interest 202 as an example. In this way, the calculation is performed on the luminance signal in the 5 × 5 pixel area centered on the target pixel 202. C in the figure represents an arrangement of K11 to K55, and d in the figure represents an example of values of K11 to K55.

  Since the low-frequency component is removed from the image signal that has passed through the HPF 362 that performs such processing, the image signal is only a high-frequency component. The high frequency component represents a steep change in the image. Since the steep change in the image mainly occurs in the contour portion of the subject, the image signal that has passed through the HPF 362 is a signal that includes a lot of information on the contour portion of the subject.

[Processing of judgment unit and correction unit]
As described above, the determination unit 363 compares the high frequency component Y_H of the Y signal with the high frequency component IR_H of the IR signal. In normal photographing, there is no significant difference between the high frequency component Y_H of the Y signal and the high frequency component IR_H of the IR signal. However, since visible light is scattered in an environment where fog or the like is generated, an image using visible light is an image in which the contour of the subject is blurred. On the other hand, since infrared light is not easily scattered, an image using infrared light is an image with relatively little outline blurring. Therefore, by comparing the high frequency components of these signals, it is possible to determine whether fog or the like has occurred. That is, the high-frequency component Y_H of the Y signal is compared with the high-frequency component IR_H of the IR signal. If the high-frequency component IR_H of the IR signal is larger, it can be determined that fog or the like has occurred. As this comparison method, a method of comparing the average value [0] of the absolute values of the high frequency component Y_H of the Y signal and the high frequency component IR_H of the IR signal in the entire screen can be used.

  As another example of the comparison method, a method of comparing the mean square values of the high frequency component Y_H of the Y signal and the high frequency component IR_H of the IR signal in the entire screen may be used.

  The correction unit 364 corrects the luminance signal Y based on the determination result of the determination unit 363. Specifically, when the determination unit 363 determines that the high-frequency component IR_H of the IR signal is larger than the high-frequency component Y_H of the Y signal, fog or the like has occurred, so that the contrast with respect to the luminance signal Y is contrasted. Y ′ signal that has been corrected to increase the frequency is generated. As a correction for increasing the contrast, for example, a method of correcting by attenuating a luminance signal in a low signal level region using an amplifier having a non-linear gain characteristic can be used.

[Correction method]
FIG. 7 is a diagram illustrating a correction method according to the first embodiment of the present technology. The figure shows a graph showing the characteristics of an amplifier having a non-linear gain characteristic used for correction. The horizontal axis of the graph represents the signal level of the input signal of the amplifier, and the vertical axis represents the gain as a ratio to the gain at the steady state. This amplifier amplifies an input signal, and its gain varies depending on the input signal level. That is, the gain gradually decreases at signal levels below the threshold. Note that the steady-state gain can be set to a value “1”, for example. Since this amplifier attenuates the luminance signal having a low signal level, the difference in signal level between the bright and dark portions of the luminance signal is increased, and the contrast is corrected. Note that gamma correction having the same function may be performed instead of such an amplifier. Specifically, the Y signal, the Cb signal, and the Cr signal are converted again into the R signal, the G signal, and the B signal, and gamma correction is performed. At this time, the gamma curve needs to be set so that the gain in the low signal level region is small.

[Signal processing procedure]
FIG. 8 is a diagram illustrating an example of a signal processing procedure according to the first embodiment of the present technology. When an image signal is input from the image sensor 200, the signal processing device 300 starts this processing. First, the signal processing device 300 performs signal conversion processing such as demosaicing on the input image signal (step S901). Next, the signal processing device 300 extracts high frequency components from the IR signal and the Y signal obtained by the signal conversion process (step S902). Thereby, the high frequency component Y_H signal of the Y signal and the high frequency component IR_H signal of the IR signal are obtained from the Y signal and the IR signal. Next, the signal processing device 300 calculates the average value of the high-frequency component Y_H signal of the Y signal and the high-frequency component IR_H signal of the IR signal (step S903), and compares these average values to make a determination (step S904). . As a result, when the average value of the high-frequency component IR_H of the IR signal is larger (step S904: Yes), the signal processing device 300 corrects the Y signal (step S905) and ends the process. On the other hand, when not large (step S904: No), the signal processing apparatus 300 skips the process of step S905 and ends the process.

  As described above, according to the first embodiment of the present technology, the high frequency component Y_H of the Y signal is compared with the high frequency component IR_H of the IR signal to determine whether fog or the like is generated. This makes it possible to make an appropriate determination even in a low-light environment such as at night. Based on this, it is possible to correct a decrease in contrast of the luminance signal and improve visibility.

<2. Second Embodiment>
In the first embodiment described above, a method of attenuating the luminance signal in the region where the signal level is low is used for correcting the luminance signal. On the other hand, in the second embodiment of the present technology, correction is performed by mixing the high-frequency component of the IR signal with the luminance signal. Thereby, a clearer image can be obtained.

[Configuration of image processing unit]
FIG. 9 is a diagram illustrating a configuration example of the image processing unit 360 according to the second embodiment of the present technology. The image processing unit 360 includes a correction unit 365 instead of the correction unit 364. In addition to the Y signal, Cb signal, and Cr signal, the correction unit 365 receives a high frequency component IR_H signal of the IR signal. Other configurations of the image processing unit 360 and the signal processing device 300 are the same as those of the image processing unit 360 and the signal processing device 300 according to the first embodiment of the present technology, and thus description thereof is omitted.

[Correction processing]
The correction unit 365 corrects the Y signal based on the result of the determination unit 363. This correction can be performed based on the following equation.
Y ′ = α × Y + (1−α) × IR_H
Where α is the mixing ratio. By setting the mixing ratio α to an arbitrary value between 0 and 1, the ratio of the high frequency component IR_H signal of the IR signal mixed with the Y signal can be changed. Thus, based on the mixing ratio α, the Y signal can be corrected by mixing the Y signal and the high frequency component IR_H signal of the IR signal. Since the high frequency component IR_H signal of the IR signal is mixed, the Y ′ signal that is the corrected signal is an image signal in which the contour of the subject is emphasized. Therefore, a clear image can be obtained.

  Thus, according to the second embodiment of the present technology, it is possible to obtain a clearer image by performing correction by adding the high-frequency component Y_H of the Y signal and the high-frequency component IR_H of the IR signal, Visibility can be improved.

  As described above, according to the embodiment of the present technology, it is possible to appropriately determine whether fog or the like is generated even in a low illumination environment such as nighttime. Based on this, visibility can be improved by correcting the luminance signal.

  The above-described embodiment shows an example for embodying the present technology, and the matters in the embodiment and the invention-specific matters in the claims have a corresponding relationship. Similarly, the invention specific matter in the claims and the matter in the embodiment of the present technology having the same name as this have a corresponding relationship. However, the present technology is not limited to the embodiment, and can be embodied by making various modifications to the embodiment without departing from the gist thereof.

  Further, the processing procedure described in the above embodiment may be regarded as a method having a series of these procedures, and a program for causing a computer to execute these series of procedures or a recording medium storing the program. You may catch it. As this recording medium, for example, a CD (Compact Disc), an MD (MiniDisc), a DVD (Digital Versatile Disc), a memory card, a Blu-ray disc (Blu-ray (registered trademark) Disc), or the like can be used.

  In addition, the effect described in this specification is an illustration to the last, Comprising: It does not limit and there may exist another effect.

In addition, this technique can also take the following structures.
(1) a filter that extracts a high-frequency component of a luminance signal and a high-frequency component of an infrared light signal;
A determination unit for determining whether or not the extracted high frequency component of the infrared light signal is larger than the extracted high frequency component of the luminance signal;
And a correction unit that corrects the luminance signal based on the result of the determination.
(2) When the determination unit determines that the extracted high frequency component of the infrared light signal is larger than the extracted high frequency component of the luminance signal, the correction unit is greater than a predetermined signal level. The signal processing apparatus according to (1), wherein the luminance signal having a low signal level is attenuated.
(3) When the determination unit determines that the high-frequency component of the extracted infrared light signal is larger than the high-frequency component of the extracted luminance signal, the correction unit adds the luminance signal to the luminance signal. The signal processing apparatus according to (1), wherein high-frequency components of the extracted infrared light signal are mixed based on a predetermined ratio.
(4) The determination unit compares the average value of the high-frequency components of the extracted luminance signal with the average value of the high-frequency components of the extracted infrared light signal to determine (1) to ( The signal processing apparatus according to 3).
(5) The determination unit makes a determination by comparing a root mean square value of high frequency components of the extracted luminance signal and a root mean square value of high frequency components of the extracted infrared light signal. To (3).
(6) an image sensor that outputs a visible light signal and an infrared light signal;
A generator for generating a luminance signal from the output visible light signal;
A filter that extracts a high-frequency component of the generated luminance signal and a high-frequency component of the output infrared light signal;
A determination unit for determining whether or not the extracted high frequency component of the infrared light signal is larger than the extracted high frequency component of the luminance signal;
An imaging apparatus comprising: a correction unit that corrects the luminance signal based on the result of the determination.
(7) an extraction procedure for extracting the high-frequency component of the luminance signal and the high-frequency component of the infrared light signal;
A determination procedure for determining whether or not the extracted high-frequency component of the infrared light signal is greater than the extracted high-frequency component of the luminance signal;
And a correction procedure for correcting the luminance signal based on the result of the determination.

DESCRIPTION OF SYMBOLS 10 Imaging device 100 Lens 200 Imaging device 201 Pixel 202 Pixel of interest 300 Signal processing device 301 Bus 310 Imaging device interface 320 Processor 330 Output interface 360 Image processing unit 361 Signal conversion unit 363 Judgment unit 364, 365 Correction unit 367 Dark current variation correction unit 368 Demosaic unit 369 YC conversion unit 370 Image compression unit 400 Image signal output unit 500 Infrared light irradiation unit

Claims (7)

A filter that extracts a high-frequency component of the luminance signal and a high-frequency component of the infrared light signal;
A determination unit for determining whether or not the extracted high frequency component of the infrared light signal is larger than the extracted high frequency component of the luminance signal;
And a correction unit that corrects the luminance signal based on the result of the determination.   The correction unit has a signal level lower than a predetermined signal level when the determination unit determines that the extracted high-frequency component of the infrared light signal is greater than the extracted high-frequency component of the luminance signal. The signal processing apparatus according to claim 1, wherein the luminance signal is attenuated.   The correction unit is extracted into the luminance signal when the determination unit determines that the extracted high-frequency component of the infrared light signal is greater than the high-frequency component of the extracted luminance signal. The signal processing apparatus according to claim 1, wherein high-frequency components of the infrared light signal are mixed based on a predetermined ratio.   The signal processing apparatus according to claim 1, wherein the determination unit makes a determination by comparing an average value of high-frequency components of the extracted luminance signal with an average value of high-frequency components of the extracted infrared light signal.   The signal processing according to claim 1, wherein the determination unit determines a comparison by comparing a root mean square value of high frequency components of the extracted luminance signal and a root mean square value of high frequency components of the extracted infrared light signal. apparatus. An image sensor that outputs a visible light signal and an infrared light signal;
A generator for generating a luminance signal from the output visible light signal;
A filter that extracts a high-frequency component of the generated luminance signal and a high-frequency component of the output infrared light signal;
A determination unit for determining whether or not the extracted high frequency component of the infrared light signal is larger than the extracted high frequency component of the luminance signal;
An imaging apparatus comprising: a correction unit that corrects the luminance signal based on the result of the determination. An extraction procedure for extracting the high-frequency component of the luminance signal and the high-frequency component of the infrared light signal;
A determination procedure for determining whether or not the extracted high-frequency component of the infrared light signal is greater than the extracted high-frequency component of the luminance signal;
And a correction procedure for correcting the luminance signal based on the result of the determination.

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