JP5668951B2 - Image input device - Google Patents

Description

  The present invention relates to an image input device including an image sensor, and more particularly to an image input device capable of forming an appropriate image even when pixels of the image sensor are saturated.

  In recent years, imaging devices that capture night scenes in color have been developed, and research is also being carried out on vehicles such as surveillance cameras and driving support systems that support driver vision during night driving. However, in general, since there is a limit to the dynamic range of the image sensor, when imaging a bright light emitter such as a halogen light signal or a car lamp, any pixel of the image sensor is saturated, The value of each color component becomes the maximum value, and the chromaticity signal may be lost. Once the chromaticity signal is lost, a color image cannot be formed properly.

  On the other hand, Patent Document 1 acquires a color image of a road, detects a road marking of the road, specifies a road marking area that includes the road marking in the image, and a signal of the road marking area is obtained. When the signal level is equal to or higher than a predetermined level set within the output range of the signal, it is determined that the signal is saturated, and the exposure amount of the imaging unit in the next control cycle is decreased in the control cycle at a predetermined time point. Technology is disclosed.

JP 2007-28279 A

  However, according to the prior art of Patent Document 1, by reducing the exposure amount, the color reproduction in the saturated region is improved, but in a region that is not saturated, the exposure amount is reduced due to a decrease in the exposure amount. There is a risk of becoming inappropriate as a color image.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an image input device that can obtain information necessary for creating an appropriate color image even when pixels are saturated.

An image input device according to claim 1 is provided.
An imaging means comprising a plurality of pixels for capturing a subject image and outputting a color image signal in response thereto;
Processing means for performing image processing on a color image signal output by the imaging means;
Detecting means for detecting that any pixel of the imaging means is saturated,
When the detection unit detects that any pixel of the imaging unit is saturated by the imaging of the imaging unit, the processing unit is output from surrounding pixels arranged around the saturated saturated pixel. Based on the color image signal, the color image signal output from the saturated pixel is corrected ,
The surrounding pixel detects a flare component, and the processing means outputs the saturated pixel from the relative relationship between the chromaticity coordinates of the color image signal output from the surrounding pixel and the origin of a predetermined chromaticity coordinate system. The chromaticity coordinates of the color image signal thus obtained are estimated and corrected .

  According to the present invention, when the detection unit detects that any pixel of the imaging unit is saturated by the imaging of the imaging unit, the processing unit is arranged around the saturated saturated pixel. Since the color image signal output from the saturated pixel is corrected based on the color image signal output from the surrounding pixel, the original image of the subject image to be captured by the saturated pixel is extracted from the color image signal output from the surrounding pixel. The color can be estimated and thereby an appropriate color image can be formed. The “surrounding pixel” includes a non-saturated pixel adjacent to the saturated pixel and a non-saturated pixel within 5 pixels from the saturated pixel.

The surrounding pixel detects a flare component, and the processing means outputs the saturated pixel from the relative relationship between the chromaticity coordinates of the color image signal output from the surrounding pixel and the origin of a predetermined chromaticity coordinate system. The chromaticity coordinates of the color image signal thus obtained are estimated and corrected . Accordingly, the original color of the subject image to be captured by the saturated pixel can be estimated using the flare component spreading around the saturated pixel, thereby forming an appropriate color image. The “origin of the chromaticity coordinate system” refers to an arbitrary point in the white area of the chromaticity coordinate system designated in advance.

The image input apparatus according to claim 2 , wherein the processing unit passes a color image signal output from the saturated pixel and the surrounding pixels through a smoothing filter, and uses the smoothed signal to output the saturated pixel. The color image signal output from is corrected. As a result, the signals of the saturated pixel and the surrounding pixels are averaged, and the original color of the subject image to be captured by the saturated pixel can be estimated. As the smoothing filter, for example, those described in WO 2006/129529 can be used.

Another image input device is
An imaging means comprising a plurality of pixels for capturing a subject image and outputting a color image signal in response thereto;
Processing means for performing image processing on a color image signal output by the imaging means;
Detecting means for detecting that any pixel of the imaging means is saturated,
The processing means stores three circular patterns arranged at specific intervals, and the detection means recognizes the three circular patterns in the obtained image by imaging by the imaging means, and one circular pattern. When it is detected that one of the pixels of the imaging unit is saturated according to the pattern, the light received by the saturated pixel depends on whether the position of the saturated pixel corresponds to one of the three circular patterns. The color is estimated to be one of blue, yellow, and red.

  For example, in traffic signals for vehicle control, the order of arrangement of shape patterns and colors is determined for each country. Therefore, if the processing means stores blue, yellow, and red circular patterns arranged at specific intervals, the detection means can detect the three circular patterns in an image obtained by imaging by the imaging means. If it is recognized and it is detected that any pixel of the imaging means is saturated according to one circular pattern, the subject image is recognized as a traffic signal for vehicle control, and the position of the saturated pixel is determined. Since the color of light received by a saturated pixel is estimated to be one of blue, yellow, and red depending on which one of the three circular patterns corresponds to, the color from the image sensor based on such information An appropriate color image can be obtained by correcting the image signal. The “specific interval” means an interval determined at a certain ratio with respect to the diameters of the blue circle, the yellow circle, and the red circle.

  ADVANTAGE OF THE INVENTION According to this invention, even when a pixel is saturated, the image input apparatus which can obtain information required for appropriate color image preparation can be provided.

It is the schematic of the image input device MG which concerns on 1st Embodiment. It is a figure which shows an example of the image imaged with the image input device MG. It is a figure which shows the overlapping condition of a saturated pixel and a high-intensity pixel. It is a figure showing a series of frames which consist of a plurality of pictures. It is the schematic of the image input device MG which concerns on 2nd Embodiment. It is a figure which shows chromaticity coordinates. It is the schematic of the image input device MG which concerns on 3rd Embodiment.

(First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of an image input device MG according to the first embodiment. Such an image input device MG can be used for an in-vehicle camera, but the application is not limited thereto, and may be a surveillance camera, for example. The image input device MG includes a lens 101, an image pickup device 102 (including an A / D conversion unit) that is an image pickup unit, an image acquisition circuit 103, an image pickup number count circuit 104, an exposure amount calculation circuit 105, an exposure amount control circuit 106, and a detection. A saturation / high luminance area detection circuit 107 as a means and a saturation area color correction circuit 108 as a processing means are provided.

  A subject image incident through the lens 101 is formed on a plurality of pixels of the image sensor 102 through an RGB color filter (not shown). As a result, an analog color image signal is generated, which is converted into a digital color image signal via the A / D converter and output. The color image signal is input to the image acquisition circuit 103 to form one image for each frame, and based on this, the number of images (number of times of imaging) is counted by the number-of-images counting circuit 104, and the exposure amount is calculated. The exposure amount is calculated by the circuit 105, and based on this, the exposure amount control circuit 106 controls the exposure amount (shutter speed) of the image sensor 102. On the other hand, based on the signal from the image acquisition circuit 103, the saturation / high luminance region detection circuit 107 detects the saturated pixel and the high luminance pixel, and the saturation region color correction circuit 108 further detects the color image signal from the saturation pixel. Is corrected and displayed via a display (not shown) or stored in a memory (not shown).

  Next, specific image processing (hereinafter referred to as interpolation image processing) of the image input device MG will be described. For example, as shown in FIG. 2, in a night scene, a subject image is formed when a high-luminance illuminant such as a red signal SR that emits halogen light or a brake lamp BL of an automobile VH is imaged in a dark environment. The pixel is likely to be saturated. However, when the pixel is saturated, the color information is lost, and there is a problem that the red signal and the lighting of the brake lamp cannot be detected. Therefore, the image input device MG according to the present embodiment performs interpolation image processing as follows.

  First, a single image Img0 is captured at a preset normal first shutter speed (first exposure amount). At this time, the image acquisition circuit 103 outputs a color image signal corresponding to the image Img0. The saturated / high luminance area detection circuit 107 to which such a color image signal is input detects the presence or absence of a saturated pixel in which the signal is saturated, and if there is a saturated pixel, detects the coordinates of the saturated pixel on the imaging surface. As the saturated pixel, a pixel having a maximum signal value (for example, R, G, B value) output from the pixel is selected. When there are saturated pixels adjacent to the saturated pixels, the total number n is counted. Note that not only a pixel having a maximum signal value output from the pixel but also a pixel having a signal value equal to or higher than a saturation threshold (for example, R, G, and B values are 95% of the maximum value) may be a saturated pixel. However, the pixel is recognized as a saturated pixel when a predetermined number or more (for example, n ≧ 5) of pixels having a signal value equal to or higher than the saturation threshold are continuously arranged. This is to avoid erroneously determining white scratches as saturated pixels.

  Next, the image input device MG sets a second shutter speed (second exposure amount smaller than the first exposure amount) faster than the first shutter speed under the control of the exposure amount control circuit 106, and sets one sheet. An image Img1 is captured. Here, the second shutter speed may be a shutter speed that is known in advance that saturated pixels are not generated even if an image of a lit red signal or a brake lamp is captured by experiment or simulation, or the shutter speed is gradually increased. (1/2, 1/4, 1/8...), A plurality of times of imaging are performed, a saturated pixel is detected each time, and a shutter speed in imaging where no saturated pixel is first detected is set to the second. It is good also as shutter speed of.

  Further, the signal value of the saturation / high luminance area detection circuit 107 is higher than the luminance threshold value (lower than the saturation threshold, for example, R, G, B values) from the color image signal obtained by imaging at the second shutter speed. Is a pixel with a luminance of less than 95% of the maximum value and 80% or more), and the coordinates thereof are detected. However, the high luminance pixel is recognized as a case where a predetermined number or more (for example, n ≧ 5) of pixels having a signal value equal to or higher than the high luminance threshold value are continuously arranged.

  Next, the image input device MG performs imaging by returning the shutter speed to the first shutter speed, and obtains an image Img2. For example, in the case of the image input device MG incorporated in an in-vehicle camera, the difference between the image Img2 and the image Img0 is mainly caused by, for example, the imaging scene changing according to the movement of the vehicle. Therefore, when the scene change is small, the image Img0 that has already been captured may be used instead of newly capturing the image Img2.

  Next, the saturation / high brightness region detection circuit 107 uses the image Img2 (or the image Img0) obtained by imaging at the first shutter speed and the image Img1 obtained by imaging at the second shutter speed. The coordinates of saturated pixels and high luminance pixels on the imaging surface are compared. If there are pixels having the same coordinates, they are assumed to be images of the same subject, and the same coordinates are set so that the saturation region color correction circuit 108 matches the chromaticity included in the signal from the high luminance pixel in the image Img1. The chromaticity included in the signal from the saturated pixel of the image Img2 (or the image Img0) having is adjusted.

  The saturated area color correction circuit 108 converts the color image signals R, G, and B into a color space that includes the luminance signal Y and the chromaticity signals Cb and Cr.

For example, the luminance signal Y and the chromaticity signals Cb and Cr are calculated by the following equations. The chromaticity signal Cb indicates the chromaticity (color difference) signal of B and the luminance signal Y, and the chromaticity signal Cr indicates the chromaticity (color difference) signal of R and the luminance signal Y.
Y = 0.3R + 0.59G + 0.11B
Cb = −0.17R−0.33G + 0.5B
Cr = 0.5R-0.42G-0.08B
Here, when the coordinates of the pixels arranged in x rows and y columns on the imaging surface are represented by (x, y), the luminance signal of the pixel I ₁ (x, y) which is one of the high luminance pixels of the image Img1. Is Y ₁ (x, y), and the chromaticity signals are Cb ₁ (x, y) and Cr ₁ (x, y). On the other hand, if there is a pixel I ₂ (x, y) having the same coordinates in the saturated pixels of the image Img2 (or image Img0), the luminance signal of the pixel I ₂ (x, y) is Y ₂ (x, y), The chromaticity signals are Cb ₂ (x, y) and Cr ₂ (x, y), but since the signal values are saturated, the values of the respective color components become maximum values, and the chromaticity signal Cb ₂ (X, y) and Cr ₂ (x, y) are close to 0. Therefore, the new chromaticity of the pixel I ₂ (x, y) of the image Img2 (or image Img0) is calculated by the following equation.

Cb ′ ₂ (x, y) = Cb ₁ (x, y) × Y ₂ (x, y) / Y ₁ (x, y) (1)
Cr ′ ₂ (x, y) = Cr ₁ (x, y) × Y ₂ (x, y) / Y ₁ (x, y) (2)
Here, the image Img2 (or image Img0) shown in FIG. 3A and the image Img1 shown in FIG. However, as indicated by hatching in FIG. 3A, the chromaticity signal of the saturated pixel PX1 (referred to as the superposed saturated pixel) of the image Img2 (or the image Img0) having the same coordinates as the high luminance pixel of the image Img1 is (1 ) And (2) can be corrected by further increasing the signal from the high luminance pixel of the image Img1 by the ratio of the luminance signal of the high luminance pixel and the luminance signal of the saturated pixel.

  On the other hand, as shown in white in FIG. 3A, the chromaticity signal of the saturated pixel PX2 (referred to as a non-polymerized saturated pixel) of the image Img2 (or the image Img0) that does not have the same coordinates as the high luminance pixel of the image Img1. Is unknown. Therefore, in such a case, as shown in FIG. 3B, the average value of the chromaticity signals of the high-luminance pixel PX3 not having the same coordinates as the superposed saturation pixel PX1 (or all) is obtained, and (1 ), Substituting into the equation (2), and correcting by substituting with the chromaticity signal of the non-polymerization saturated pixel PX2 adjacent to the superposition saturation pixel PX1. This is because the saturated pixel is estimated to be saturated by monochromatic light emitted from a high brightness subject such as a red signal or a brake lamp. However, the corrected chromaticity signal of the non-polymerization saturated pixel PX2 adjacent to the superposition saturation pixel PX1 may be replaced with the chromaticity signal of the superposition saturation pixel PX1.

In this way, in the image Img2 (or the image Img0), the luminance signal Y ₂ (x, y) of all the saturated pixels and the corrected chromaticity signals Cb ′ ₂ (x, y), Cr ′ ₂ (x, y) can be determined.

  Furthermore, the image input device MG can also correct luminance other than the saturated pixels of the image Img2 (or the image Img0) using the signal of the image Img1. In this correction, first, the coordinates of pixels other than the high luminance pixels (referred to as low luminance pixels) in the image Img1 and the coordinates of pixels other than the saturated pixels (referred to as non-saturated pixels) in the image Img2 (or the image Img0) are compared. To do. When there is a pixel having the same coordinates, the luminance signal of the non-saturated pixel is replaced with the luminance signal of the corresponding low luminance pixel.

  On the other hand, if there is no pixel having the same coordinates, the average value of the luminance signals of the pixels around the low luminance pixel is obtained, and the luminance signal of the unsaturated pixel is replaced with the average value. In this way, since the luminance signal and chromaticity signal of all the pixels can be obtained in the image Img2 (or the image Img0), RGB values can be calculated from this to output an appropriate color image signal. it can.

  The image input device MG can repeatedly capture images at the first shutter speed and the second shutter speed for each frame. As shown in FIG. 4, a saturated pixel is detected from an image A captured at the first shutter speed, and the saturation of the previous image A is detected from the signal of the high-luminance pixel of the image B captured at the second shutter speed. The pixel signal is corrected. At this time, only the corrected image A is displayed without displaying the image B in which the pixels are not saturated. Therefore, every other frame displays a moving image frame. Note that a plurality of (for example, two) images A can be corrected from the signal of the high-luminance pixel of one image B. Therefore, the frames in this case are arranged in the order of B, A, A, B, A, A..., But only the corrected image A is displayed. There may be three or more images A between the images B and B.

  When the number-of-images counting circuit 104 counts the number of images captured at the first shutter speed and detects that the integrated number has reached a predetermined number, the exposure amount control circuit 106 It is possible to control the exposure amount so that imaging is performed at the second shutter speed so that the saturated region detected from the number of images is not saturated.

  The interpolated image processing described above need not be performed unless the saturated / high brightness area detection circuit 107 detects a saturated pixel. This is to eliminate useless processing. The interpolation image processing may be performed after the saturation / high luminance area detection circuit 107 detects a saturated pixel.

  Furthermore, it is possible to align the saturation pixel and the high luminance pixel on the imaging surface in anticipation of the movement of the subject. For example, when imaging is performed with an in-vehicle camera, a fixed object such as a traffic light moves on the screen in accordance with the movement of the vehicle. Therefore, the current vehicle speed and frame interval are used to detect the direction and amount of movement of the subject on the imaging surface, suppressing positional deviation in the previous and next frames, and accurately aligning saturated pixels and high-brightness pixels. Can be done.

  Further, when the frequency of occurrence of saturated pixels is low (for example, the number of occurrences of saturated pixels in 30 frames is less than or equal to a threshold value), the frequency of interpolation image processing described above may be reduced or no interpolation image processing may be performed. . This is because the user may not be concerned if the frequency of occurrence of saturated pixels is low, thereby eliminating waste of processing.

Furthermore, the frequency of the above-described interpolation image processing can be adjusted in conjunction with the speed of the vehicle. For example, when the vehicle speed is high, the frequency of the interpolation image processing is decreased, and when the vehicle speed is low, the frequency of the interpolation image processing is increased. As a result, it becomes easy to interpolate saturated pixels and high-luminance pixels, and it is possible to suppress a coordinate shift between pixels in the same region in the preceding and following frames.
(Second Embodiment)
FIG. 5 is a schematic diagram of an image input device MG according to the second embodiment. The image input device MG includes a lens 101, an image sensor 102 (including an A / D conversion unit) that is an imaging unit, an image acquisition circuit 103, a saturation region detection circuit 111 that is a detection unit, a flare region detection circuit 112, and a processing unit. A saturation region color correction circuit 113 is included. The image sensor 102 and the image acquisition circuit 103 are the same as those in the above-described embodiment. Moreover, the detection of a saturated pixel can be performed similarly to the process mentioned above.

  The image processing of the image input device MG will be described. For example, as shown in FIG. 2, when a bright scene such as a red signal SR that emits halogen light or a brake lamp BL of an automobile VH is imaged in a night scene, the subject image is formed. When the selected pixel is saturated, the surrounding pixels are likely to detect the flare light FL. Flare light often occurs due to ghost or stray light when a high-luminance subject is imaged.

  When the saturated region detection circuit 111 detects a saturated pixel in the same manner as in the first embodiment described above, the flare region detection circuit 112 detects a pixel that receives flare light (referred to as a flare pixel). Note that if there is an unsaturated pixel adjacent to the saturated pixel, it can be estimated as a flare pixel.

  Further, the flare area detection circuit 112 calculates the average value Yf of the luminance signal included in the signal from the flare pixel and the average values Cbf and Crf of the chromaticity signal.

  Here, in the stored chromaticity coordinate system of the safe color light of the JIS standard shown in FIG. 6, the saturation region color correction circuit 113 stores the average values Cbf and Crf (chromaticity coordinates) of the chromaticity signals included in the signal from the flare pixel. ) As a point P. Furthermore, when the center of the white area WR is set as the origin O, a straight line is drawn from the origin O to the point P, and when the point P side of the straight line is extended, the extension line passes through the red area RR and is saturated. It is estimated that the subject light imaged on the pixel inherently contains red. Accordingly, by correcting the chromaticity signal of the saturated pixel in accordance with the red color of the JIS standard safe color light, an appropriate RGB value of the captured image can be obtained. Obviously, when the extension line passes through the yellow region YR, the subject light imaged on the saturated pixel inherently contains yellow, and when the extension line passes through the green region GR, It can be estimated that the subject light imaged on the saturated pixel inherently contains green, and can be corrected similarly.

  In general, flare light has a color that blurs around the high-intensity light source, and the chromaticity does not necessarily match that of the light source. On the other hand, the JIS standard defines the range of chromaticity coordinates of colors such as traffic lights and automobile lamps. Therefore, the saturated area color correction circuit 113 stores them in advance and estimates the closest chromaticity as the chromaticity in the saturated pixel signal using the average chromaticity signal from the flare pixel.

  Note that not only a pixel adjacent to a saturated pixel but also a non-saturated pixel within 5 pixels from the saturated pixel may be recognized as a flare pixel.

As another image processing, the saturation region color correction circuit 113 smoothes a signal from a pixel in a region including a saturated pixel and a non-saturated pixel (including within 5 pixels) adjacent thereto by passing the signal through a smoothing filter. It is also possible to create a signal and replace it with a signal from a saturated pixel. If the signal from the pixel in the region including the saturated pixel and the adjacent unsaturated pixel is passed through the smoothing filter, the surrounding color can be lost to the saturated region. It is because the color of can be estimated. In such an example, the flare area detection circuit 112 is unnecessary.
(Third embodiment)
FIG. 7 is a schematic diagram of an image input device MG according to the third embodiment. The image input device MG includes a lens 101, an image sensor 102 (including an A / D converter) that is an imaging unit, an image acquisition circuit 103, a traffic light detection circuit 114 and a lighting signal detection circuit 115 that are detection units, and a signal position detection circuit. 116, a signal color estimation circuit 117 and a signal color provision circuit 118 as processing means. The image sensor 102 and the image acquisition circuit 103 are the same as those in the above-described embodiment. Moreover, the detection of a saturated pixel can be performed similarly to the process mentioned above.

  The image input device MG according to the present embodiment detects a traffic light using a pattern recognition technique. Specifically, the processing means stores three circular patterns arranged at specific intervals, and the traffic light detection circuit 114 has a size at a short distance in the color image signal output from the image acquisition circuit 103. Can be recognized as a traffic light if there is a subject that includes three circles that are substantially equal and whose centroids are aligned horizontally or vertically.

  By the way, in a night scene, when any color of a traffic light emits light, a saturated pixel may be generated, and there is a possibility that a lighted color may not be understood. However, the shape and lighting color of traffic lights are determined by the rules of each country. For example, in Japan, the lighting colors are “blue, yellow, red” in order from the left. Therefore, when the lighting signal detection circuit 115 detects that one of the pixels is saturated according to one circular pattern, the signal color estimation circuit 117 has a left circle among the pixels corresponding to the three circles. If the pixel corresponding to is a saturated pixel, it is determined that blue light is projected from the pixel. If the pixel corresponding to the center circle is a saturated pixel, yellow light is projected from the pixel. If the pixel corresponding to the right circle is a saturated pixel, it can be determined that red light is projected from the pixel. The signal color assigning circuit 118 corrects the chromaticity signal from the saturated pixel to any one of blue, yellow, and red according to the chromaticity coordinate system of the safe color light shown in FIG. The luminance signal of the saturated pixel may be an average value of the luminance signals of the pixels corresponding to the three detected circles. By correcting the chromaticity signal of the saturated pixel as described above, an appropriate RGB value of the captured image can be obtained.

  The signal position detection circuit 116 may obtain the latitude / longitude of the traffic light from, for example, GPS information, etc., and let the traffic light detection circuit 114 detect the traffic light only when traveling near the latitude / longitude where the traffic light is located. good. Thereby, the false detection of a traffic signal can be suppressed.

  The present invention can be applied to in-vehicle cameras, surveillance cameras, and the like, but the application is not limited thereto.

DESCRIPTION OF SYMBOLS 101 Lens 102 Image pick-up element 103 Image acquisition circuit 104 Image pick-up number count circuit 105 Exposure amount calculation circuit 106 Exposure amount control circuit 107 Saturation / high brightness area detection circuit 108 Saturation area color correction circuit 111 Saturation area detection circuit 112 Flare area detection circuit 113 Saturation Area color correction circuit 114 Signal detection circuit 115 Lighting signal detection circuit 116 Signal position detection circuit 117 Signal color estimation circuit 118 Signal color assignment circuit BL Brake lamp FL Flare light MG Image input device O Origin P point PX1 Polymerization saturation pixel PX2 Nonpolymerization saturation Pixel PX3 High brightness pixel RR Red area SR Red signal VH Car WR White area

Claims (2)

An imaging means comprising a plurality of pixels for capturing a subject image and outputting a color image signal in response thereto;
Processing means for performing image processing on a color image signal output by the imaging means;
Detecting means for detecting that any pixel of the imaging means is saturated,
When the detection unit detects that any pixel of the imaging unit is saturated by the imaging of the imaging unit, the processing unit is output from surrounding pixels arranged around the saturated saturated pixel. Based on the color image signal, the color image signal output from the saturated pixel is corrected ,
The surrounding pixel detects a flare component, and the processing means outputs the saturated pixel from the relative relationship between the chromaticity coordinates of the color image signal output from the surrounding pixel and the origin of a predetermined chromaticity coordinate system. An image input apparatus characterized by correcting and correcting the chromaticity coordinates of a color image signal .   The processing means passes the color image signal output from the saturated pixel and the surrounding pixels through a smoothing filter, and corrects the color image signal output from the saturated pixel using the smoothed signal. The image input device according to claim 1, wherein: