JP2017059980A - Imaging device and control method for imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device capable of reducing the false color effectively at a low cost.SOLUTION: A first detector Det1 generates a first detection value depending on the area of a specific color corresponding to a false color contained in each frame, on the basis of a video signal (RGB signal Srgb4) obtained by imaging a subject. A color adjustment section 14 adjusts the saturation of the video signal. On the basis of the first detection value, a control section 10 controls the color adjustment section 14 so as to reduce the saturation of a specific color of the video signal, when the ratio of the area of a specific color contained in each frame is less than a predetermined threshold.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus capable of reducing false colors and a method for controlling the imaging apparatus.

  In an image pickup apparatus that generates a video signal by photoelectrically converting light from a subject using an image pickup device, a false color different from the original color may occur depending on the shooting conditions for shooting the subject. When a subject with a large difference in brightness is photographed with an imaging apparatus equipped with an inexpensive optical system, false colors due to lens aberrations are likely to occur.

  Purple false color often occurs and is called purple fringe. Purple fringes are particularly desirable for false colors, so it is desirable to reduce them.

Japanese Patent No. 4770154

  Patent Document 1 describes a reduction method for reducing purple fringing. The reduction method described in Patent Document 1 is inevitably large in circuit scale, resulting in high costs. It is difficult to adopt a high-cost reduction method for an imaging apparatus equipped with an inexpensive optical system. There is a need for a reduction method that can effectively reduce false colors such as purple fringe at low cost.

  In order to meet such a demand, an object of the present invention is to provide an imaging apparatus and a control method for the imaging apparatus that can effectively reduce false colors at low cost.

  In order to solve the above-described problems of the conventional technology, the present invention is based on a video signal obtained by capturing an image of a subject, in accordance with a specific color area corresponding to a false color included in each frame. A first detection unit that generates one detection value; a color adjustment unit that adjusts the saturation of the video signal; and an area of the specific color included in each frame based on the first detection value. And a control unit that controls the color adjusting unit to reduce the saturation of the specific color of the video signal when the ratio is less than a predetermined threshold.

  In addition, in order to solve the above-described problems of the related art, the present invention provides a specific color corresponding to a false color in the video signal by a color adjustment unit that adjusts the saturation of the video signal obtained by imaging the subject. The image pickup apparatus is activated in a state where the saturation of the image is reduced by a preset maximum reduction amount, and after the image pickup apparatus is activated, the detection unit sets the area of the specific color included in each frame of the video signal. When the ratio of the area of the specific color included in each frame is less than a predetermined threshold based on the detection value, the ratio of the area of the specific color is generated by the color adjustment unit. The saturation of the specific color is reduced according to the detection value, and when the ratio of the area of the specific color included in each frame is equal to or greater than the threshold based on the detection value, by the color adjustment unit, A control method of an imaging device and sets the degree of serial specific color saturation adjustment of the fixed upper limit value regardless of the ratio of the area of the specific color.

  According to the imaging apparatus and the imaging apparatus control method of the present invention, it is possible to effectively reduce false colors at low cost.

It is a block diagram which shows the imaging device of one Embodiment. It is a figure for demonstrating the block division of the frame performed with the imaging device of one Embodiment. It is a figure which shows an example of the state in which the false color has generate | occur | produced around the high-intensity in a flame | frame. FIG. 10 is a characteristic diagram illustrating an example of characteristics when adjusting the saturation according to the area ratio of a specific color in the imaging apparatus according to the embodiment. It is a figure which shows an example of how saturation is adjusted corresponding to the temporal change of the area ratio of a specific color in the imaging device of one Embodiment. It is a figure which shows an example of how saturation is adjusted corresponding to the temporal change of the presence or absence of a high-intensity part in the imaging device of one Embodiment. In the imaging device of one embodiment, it is a characteristic diagram showing a first example in which the characteristics when adjusting the saturation according to the area ratio of a specific color differ according to the aperture value set for the aperture. In the imaging device of one embodiment, it is a characteristic diagram showing the 2nd example which changes the characteristic at the time of adjusting saturation according to the area ratio of a specific color according to the diaphragm value set to the diaphragm. In the imaging device of one embodiment, it is a characteristic diagram showing the 3rd example which changes the characteristic at the time of adjusting saturation according to the area ratio of a specific color according to the diaphragm value set to the diaphragm. 6 is a flowchart for explaining an operation of the imaging apparatus according to the embodiment and a process executed by the control method of the imaging apparatus according to the embodiment. It is a figure for demonstrating an example of the specific operation | movement of the imaging device of one Embodiment.

  Hereinafter, an imaging apparatus and an imaging apparatus control method according to an embodiment will be described with reference to the accompanying drawings.

  In FIG. 1, light from a subject is input to the image sensor 3 via a zoom lens 1z, a diaphragm 2, a focus lens 1f, and the like. Actually, the imaging apparatus includes a larger number of lenses, but is illustrated here in a simplified manner. The image sensor 3 is, for example, a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

  The state of opening / closing of the diaphragm 2 is controlled by the control unit 10. Although not shown in FIG. 1, the positions of the zoom lens 1z and the focus lens 1f in the optical axis direction are also controlled by the control unit 10. The control part 10 can be comprised by CPU (Central Processing Unit), for example.

  The image sensor 3 photoelectrically converts the input light and outputs an analog RGB signal Srgb1. The RGB signal Srgb1 is, for example, a video signal having a resolution of full high-definition (full HD) or a video signal having a resolution four times that of full HD called 4K.

  The image sensor 3 is a so-called single-plate image sensor having a Bayer array color filter. The RGB signal Srgb1 includes a horizontal row in which R (red) pixel signals and G (green) pixel signals are alternately arranged in a frame, a B (blue) pixel signal, and a G pixel signal. Is a signal in which horizontal rows alternately arranged are alternately arranged in the vertical direction.

  The analog amplifier 4 amplifies the RGB signal Srgb1 with a predetermined amplification gain under the control of the control unit 10 and outputs the amplified RGB signal Srgb2.

  The A / D converter 5 performs A / D conversion on the RGB signal Srgb2 and outputs a digital RGB signal Srgb3. The RGB signal Srgb3 is supplied to the demosaic processing unit 6. As described above, the RGB signal Srgb1 is a signal in which R, G, and B pixel signals are mixed in a frame.

  The demosaic processing unit 6 interpolates the R pixel signal at the pixel position where the R pixel signal does not exist in the RGB signal Srgb3 using the surrounding R pixel signals. The demosaic processing unit 6 interpolates the G pixel signal at the pixel position where the G pixel signal does not exist in the RGB signal Srgb3 using the surrounding G pixel signals. The demosaic processing unit 6 interpolates the B pixel signal at the pixel position where the B pixel signal does not exist in the RGB signal Srgb3 using the surrounding B pixel signal.

  As described above, the demosaic processing unit 6 generates the RGB signal Srgb4 including the R, G, and B frames. The RGB signal Srgb4 is supplied to the color detection unit 7, the luminance detection unit 11, and the color adjustment unit 14. The RGB signal is an example of the form of the video signal.

  As shown in FIG. 2, the color detection unit 7 divides the pixels of each frame F of the input RGB signal Srgb4 into, for example, 24 divisions in the horizontal direction and 20 divisions in the vertical direction to 480 blocks Bk. .

  In this embodiment, a case where the false color to be reduced is purple fringe will be described as an example. The color detection unit 7 calculates the average value of the amplitude values of the R signal, the G signal, and the B signal of the RGB signal Srgb4 for each block Bk. The color detection unit 7 detects whether each block Bk is purple based on the amplitude values of the R signal, the G signal, and the B signal.

  Since magenta is a color close to purple, the color detection unit 7 may detect whether or not each block Bk exhibits magenta by detecting whether each block Bk exhibits magenta. .

  In the present embodiment, detecting whether or not each block Bk is purple does not only detect whether or not the block itself is purple but also whether or not magenta is displayed as a substitute for purple. Detecting.

  By the way, in general, the imaging apparatus divides the pixel of the frame F into a plurality of blocks Bk as described above in order to adjust the white balance, and the value of (RG) and the value of (BG). And a circuit for calculating the ratio of the R signal and the B signal based on the G signal. That is, the color detection unit 7 can use a circuit that is normally included in an imaging apparatus.

  Therefore, the imaging apparatus of the present embodiment can detect whether or not each block Bk is purple using a function that an existing imaging apparatus normally has. Therefore, the color detection unit 7 for detecting whether or not each block Bk is purple does not increase the cost.

  The threshold value setting unit 8 is set with a threshold value for detecting whether or not the color detection unit 7 is purple. If the G / R and G / B values are less than a predetermined ratio with respect to the achromatic G / R and G / B values, it can be determined that the color is purple. In the threshold setting unit 8, a predetermined ratio for determining that the color is purple is set as the threshold.

  The threshold set in the threshold setting unit 8 is preferably changeable by control by the control unit 10. If the threshold value can be changed, a false color other than purple can be detected.

  As illustrated in FIG. 3, it is assumed that a part of the frame F includes a high luminance portion Ph including a plurality of blocks Bk having a high luminance equal to or higher than a predetermined luminance. In such a case, purple fringes are likely to occur around the high luminance portion Ph, and a purple-colored block Bkp is generated around the high luminance portion Ph.

  The count unit 9 counts the number of blocks Bk (block Bkp) detected as being purple in each frame F. The count value counted by the count unit 9 is supplied to the control unit 10.

  The color detection unit 7, the threshold setting unit 8, and the count unit 9 correspond to the area of the specific color corresponding to the false color included in each frame F based on the RGB signal Srgb 4 obtained by imaging the subject. It operates as a first detection unit Det1 that generates a first detection value.

  Similar to the color detection unit 7, the luminance detection unit 11 divides the pixels of each frame F of the input RGB signal Srgb4 into 480 blocks Bk. The luminance detection unit 11 calculates an average luminance value for each block Bk based on the amplitude values of the R signal, the G signal, and the B signal, and whether or not each block Bk is a high luminance unit having a predetermined luminance value or more. To detect.

  The luminance detection unit 11 operates as a second detection unit Det2 that detects whether or not each frame F includes a high luminance part having a predetermined luminance or higher based on the RGB signal Srgb4.

  Information on whether or not the luminance detection unit 11 includes a block Bk in which each frame F is a high luminance unit is supplied to the control unit 10.

  The color adjustment unit 14 adjusts the color of the input RGB signal Srgb4 based on the control by the control unit 10, and outputs the RGB signal Srgb5. The RGB signal Srgb5 is supplied to a display (not shown) mounted on the imaging apparatus and displayed as a video. The RGB signal Srgb5 may be supplied to and recorded in a recording unit (not shown) mounted on the imaging device.

  As will be described later, the color adjustment unit 14 may adjust the color of the RGB signal Srgb4 to obtain the adjusted RGB signal Srgb5, or may output the RGB signal Srgb4 as it is without adjusting the color of the RGB signal Srgb4. . In either case, for the sake of convenience, the output signal from the color adjustment unit 14 will be referred to as RGB signal Srgb5.

  Note that the color adjustment unit 14 performs color management processing on the RGB signal Srgb4 in order to obtain an image with an appropriate color. The fact that the color adjusting unit 14 outputs the RGB signal Srgb4 as it is means that the color of the RGB signal Srgb4 is not adjusted, as will be described later. The color adjustment unit 14 outputs an RGB signal Srgb5 obtained by performing color management processing on the RGB signal Srgb4 regardless of whether the color of the RGB signal Srgb4 is adjusted or not.

  The control unit 10 controls the color adjustment of the RGB signal Srgb4 in the color adjustment unit 14 according to at least the count value input from the count unit 9. Preferably, the control unit 10 controls the color adjustment of the RGB signal Srgb4 in the color adjustment unit 14 in accordance with the count value input from the count unit 9 and the detection information input from the luminance detection unit 11.

  More preferably, the control unit 10 determines the color adjustment unit 14 according to the count value input from the count unit 9, the detection information input from the luminance detection unit 11, and the aperture value set for the aperture 2. Controls the color adjustment of the RGB signal Srgb4.

  The operation unit 12 includes at least an operation button for turning on and off the imaging apparatus. The operation unit 12 may be provided in the housing of the imaging device, or may be a remote controller that is separate from the imaging device.

  When an instruction to turn on the power of the imaging apparatus is given by the operation unit 12, the power supply unit 13 supplies power to each unit that requires power under the control of the control unit 10. When an instruction to turn off the power of the imaging apparatus is given by the operation unit 12, the power supply unit 13 cuts off the power supply to each unit under the control of the control unit 10.

<Example of saturation adjustment of specific color according to area ratio of specific color>
First, a basic configuration in which the control unit 10 controls the color adjustment of the RGB signal Srgb4 in the color adjustment unit 14 according to the count value input from the count unit 9 will be described.

  When an instruction to turn on the power of the imaging device is given by the operation unit 12, the control unit 10 controls the power supply unit 13 to supply power to each unit and activates the imaging device. At this time, the control unit 10 controls the color adjustment unit 14 so that the purple saturation is reduced to 70%. In other words, the imaging device is activated in a state where the purple saturation is reduced to 70%.

  When the photographing of the subject by the imaging device is started, a count value obtained by counting the number of blocks Bk exhibiting purple is input to the control unit 10. As shown in FIG. 4, the control unit 10 is set with a relationship between a specific color area ratio (here, a purple area ratio) and a saturation adjustment amount.

  In FIG. 4, a saturation adjustment amount of 100% is a state where the saturation of a specific color is not reduced. At this time, the color adjusting unit 14 outputs the RGB signal Srgb4 as it is as the RGB signal Srgb5 without adjusting the saturation of the specific color in the input RGB signal Srgb4.

  In FIG. 4, for example, a saturation adjustment amount of 70% is a state in which the saturation of a specific color is reduced by 30%. At this time, the color adjustment unit 14 adjusts the saturation of the specific color in the input RGB signal Srgb4 to 70%, which is reduced by 30%, and outputs the RGB signal Srgb5.

  Based on the input count value, if the specific color area ratio is less than 8%, the control unit 10 reduces the purple saturation to 70% or more and less than 100% based on the characteristics shown in FIG. The adjustment unit 14 is controlled. If the specific color area ratio is 8% or more, the control unit 10 controls the color adjustment unit 14 so that the purple saturation is 100%. That is, the control unit 10 does not reduce the purple saturation when the specific color area ratio is 8% or more.

  If the area ratio of purple in one frame F is a small area of less than 8%, the purple-colored block Bk has a high possibility that the subject is not actually purple but purple fringe. On the other hand, if the area ratio of purple is 8% or more, the block Bk exhibiting purple has a high possibility that the subject actually exhibits purple.

  The threshold value of 8% of the purple area ratio is the optimum value selected by the verification by the present inventors. However, as will be described later, the optimum threshold value may vary depending on various conditions.

  According to the imaging apparatus of the present embodiment, the control unit 10 controls the color adjustment unit 14 to reduce the purple saturation when the area ratio of purple is less than 8%, thereby reducing purple fringes, It can be visually inconspicuous.

  When it is detected that the subject is actually purple and the area ratio of purple is 8% or more, the purple saturation is two or three frames after the imaging device starts photographing the subject. 100%. Therefore, the user hardly feels uncomfortable in a state where the saturation immediately after the start of photographing is reduced.

  By the way, the process of reducing the purple saturation in the RGB signal Srgb4 to which the color adjusting unit 14 is input is performed on the entire frame F. The purple saturation reduction process does not particularly affect the portion of the frame F that does not exhibit purple. Therefore, the captured image other than the purple fringe portion is not adversely affected.

  The color adjustment unit 14 divides the frame F into a plurality of regions in the same manner as in FIG. 2 and executes a process of reducing purple saturation only for the RGB signal Srgb4 in the portion where the purple fringe is generated. It is also possible to configure as described above.

  If the purple area ratio changes frequently around 8%, the purple saturation will frequently increase and decrease to cause a color hunting phenomenon. In order to suppress the hunting phenomenon, it is preferable that the control unit 10 controls the color adjustment unit 14 so as to gradually adjust purple saturation by providing a predetermined time constant.

  FIG. 5A shows an example in which the purple area ratio changes around 8% with the passage of time. FIG. 5B shows a change in the amount of purple saturation adjustment by the color adjusting unit 14 based on the control of the control unit 10 corresponding to FIG.

  When the purple area ratio changes from 8% or more to less than 8%, it is preferable that the color adjusting unit 14 gradually reduces the saturation over a period of, for example, about 1 second. When the purple area ratio changes from less than 8% to 8% or more, it is preferable that the color adjusting unit 14 immediately sets the saturation to 100%.

  That is, when the area ratio of the specific color changes from the threshold value or more to the threshold value, the control unit 10 reduces the saturation of the specific color over the first time, and the area ratio of the specific color is less than the threshold value or more than the threshold value. When the change is made, the saturation of the specific color is increased over a second time shorter than the first time.

  As described above, when the purple saturation is increased or decreased, the control unit 10 may control the color adjusting unit 14 to perform a hysteresis operation.

<Example of saturation adjustment of specific color according to area ratio of specific color and presence / absence of high luminance part>
In addition to the basic configuration described above, a preferable configuration in which the control unit 10 controls the adjustment of the color of the RGB signal Srgb4 according to the detection information input from the luminance detection unit 11 will be described.

  As described with reference to FIG. 3, if the frame F includes the high luminance portion Ph, it is highly possible that purple fringes have occurred. Therefore, if the frame F includes at least one high-luminance block Bk, the control unit 10 always reduces the purple saturation to 70% which is the preset maximum reduction amount regardless of the purple area ratio. It is preferable to control the color adjusting unit 14 so as to achieve the above state.

  Based on the detection information, the control unit 10 reduces the purple saturation to 70% when the frame F includes at least one high-brightness block Bk, and if the frame F does not include the high-brightness block Bk, as shown in FIG. The purple saturation is adjusted according to the purple area ratio. The control unit 10 may reduce the purple saturation to 70% when the block Bk of a plurality of high luminance portions is included.

  If the presence / absence of the high-luminance portion changes frequently, the purple saturation will frequently increase and decrease, and a color hunting phenomenon will occur. In order to suppress the hunting phenomenon, the control unit 10 may control the color adjustment unit 14 to perform a hysteresis operation, similarly to the case where the purple area ratio changes.

  As shown in FIG. 6A, when the luminance value of any one of the blocks Bk exceeds the threshold value indicated by the broken line, the luminance detecting unit 11 determines that the block Bk is a high luminance part, and the frame F Suppose that detection information indicating that a high luminance part is included is output. Here, the area ratio of purple is continuously 8% or more.

  As shown in FIG. 6B, when the control unit 10 changes from the frame F not including the high luminance portion to the frame F including the high luminance portion, the saturation of the specific color is instantaneously (first Reduce to maximum reduction amount (in time).

  When the control unit 10 changes from the frame F including the high luminance part to the frame F not including the high luminance part (and when the area ratio of the specific color is equal to or greater than the threshold value), the control unit 10 The saturation of a specific color is increased to 100% over 2 hours.

<Example of saturation adjustment of specific color according to area ratio of specific color, presence / absence of high luminance part and aperture value>
A more preferable configuration in which the control unit 10 controls the adjustment of the color of the RGB signal Srgb4 according to the aperture value indicating the open / close state of the aperture 2 in addition to the area ratio of the specific color and the presence / absence of the high luminance portion will be described. .

  As the aperture stop 2 opens, lens aberration called axial chromatic aberration increases, so that purple fringe tends to increase. Therefore, it is preferable to adjust the purple saturation according to the aperture value of the aperture 2.

  FIG. 7 shows an example in which the threshold value of the purple area ratio is set to a value larger than 8% as the diaphragm 2 is opened. When the aperture value is F2.0 or more, the same characteristics as in FIG. 4 are obtained. When the aperture value is F1.2, the control unit 10 sets the threshold value of the purple area ratio to 16%, for example. When the aperture value is between F2.0 and F1.2, the control unit 10 sets the threshold value to a value between 8% and 16%, which is a larger value as the aperture value is opened, as indicated by a one-dot chain line. To do.

  FIG. 8 shows an example in which the threshold value of the purple area ratio is fixed at 8%, and the purple saturation is further reduced as the diaphragm 2 is opened. When the aperture value is F2.0 or more, the same characteristics as in FIG. 4 are obtained. When the aperture value is F1.2, the control unit 10 sets the maximum reduction amount of purple saturation to 50%, for example.

  When the aperture value is between F2.0 and F1.2, the control unit 10 increases the maximum reduction amount as the aperture 2 is opened, as indicated by the alternate long and short dash line.

  FIG. 9 is an example in which the upper limit value of purple saturation is suppressed to a constant value lower than 100% as the diaphragm 2 is opened. When the aperture value is F2.0 or more, the same characteristics as in FIG. 4 are obtained. The control unit 10 sets the upper limit value of purple saturation to 80% when the aperture value is F1.2.

  When the aperture value is between F2.0 and F1.2, the control unit 10 decreases the upper limit value between 100% and 80% as the aperture 2 is opened, as indicated by the alternate long and short dash line. To do. In other words, the control unit 10 limits the saturation by increasing the amount of reduction in purple saturation as the diaphragm 2 is opened.

  In the example of FIG. 9, in addition to limiting the upper limit value of the saturation, the threshold value for reducing the saturation changes according to the purple area ratio.

  7 to 9, the aperture value may be F2.0 or more, and the aperture value may be F2.8 or more, and the aperture value F2.0 is an example.

  With reference to FIG. 10, the operation of the imaging apparatus of the present embodiment and the processing executed by the imaging apparatus control method of the present embodiment will be described. FIG. 10 shows a case where purple saturation is adjusted according to the presence / absence of a high luminance portion.

  In FIG. 10, the control unit 10 determines whether or not a power-on operation has been performed in step S1. If the power-on operation is not performed (NO), the control unit 10 repeats the process of step S1. If a power-on operation is performed (YES), the controller 10 sets the saturation adjustment amount to the maximum reduction amount and activates the imaging apparatus in step S2.

  Note that when the purple saturation is adjusted according to the aperture value as described with reference to FIG. 8, the maximum reduction amount of the saturation adjustment amount in step S2 is a value changed according to the aperture value.

  After activation of the imaging apparatus, the control unit 10 determines whether or not the frame F includes a high luminance part in step S3. If the high luminance part is included (YES), the control unit 10 maintains the saturation adjustment amount at the maximum reduction amount in step S4, and shifts the processing to step S8.

  If the high luminance part is not included (NO), the control unit 10 determines whether or not the area ratio of the specific color is less than the threshold in step S5. Note that, as described with reference to FIGS. 7 and 9, when the purple saturation is adjusted according to the aperture value, the threshold value in step S5 is a value changed according to the aperture value.

  If the area ratio of the specific color is less than the threshold (YES), the control unit 10 sets the saturation adjustment amount according to the area ratio in step S6, and shifts the processing to step S8. If the area ratio of the specific color is not less than the threshold (NO), the control unit 10 sets the saturation adjustment amount to a certain upper limit value in step S7, and shifts the processing to step S8.

  Setting the saturation adjustment amount to a certain upper limit value means that in the examples of FIGS. 4, 7, and 8, the saturation adjustment amount is 100%, that is, the saturation is not reduced. In the example of FIG. 9, setting the saturation adjustment amount to a certain upper limit value means that the saturation adjustment amount is set to an upper limit value corresponding to each aperture value.

  In step S8, the control unit 10 determines whether or not a power-off operation has been performed. If the power-off operation is not performed (NO), the control unit 10 returns the process to step S3 and repeats the processes after step S3. If a power-off operation is performed (YES), the control unit 10 turns off the power of the imaging apparatus in step S9 and ends the process.

  An example of a specific operation of the imaging apparatus according to the present embodiment will be described with reference to FIG. As shown in FIG. 11A, it is assumed that the brightness of the surrounding area where the subject is photographed decreases and becomes darker as time elapses.

  As shown in FIG. 11B, the control unit 10 linearly opens the diaphragm 2 as the surroundings become darker. In general, the control unit 10 opens the diaphragm 2 to F1.2 as the surrounding becomes dark. In the imaging apparatus of the present embodiment, when the diaphragm 2 is opened to F2.0 at time t1, the control unit 10 temporarily fixes the diaphragm 2 to F2.0 after time t1.

  As shown in FIG. 11C, the control unit 10 linearly increases the amplification gain for the RGB signal Srgb1 in the analog amplifier 4 from the minimum value after the time t1. When the amplification gain for the RGB signal Srgb1 reaches the maximum value at time t2, the control unit 10 fixes the amplification gain to the maximum value.

  In this way, the control unit 10 does not open the aperture 2 and brighten the captured image during the period from time t1 to time t2 when the aperture value of the aperture 2 is fixed at F2.0, but instead of the analog amplifier 4 By increasing the amplification gain at, the captured video is brightened.

  As described above, when the aperture 2 is opened, the axial chromatic aberration tends to increase and the purple fringe tends to increase. In the example shown in FIG. The increase can be suppressed.

  As shown in FIG. 11B, the control unit 10 linearly opens the diaphragm 2 to the diaphragm value F1.2 as the surroundings become dark after time t2. When the aperture 2 is opened beyond the aperture value F2.0, purple fringe increases. Therefore, as illustrated in FIG. 11D, the control unit 10 switches the function for reducing the saturation of the specific color described above from OFF to ON at time t2.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. In addition to the basic configuration for adjusting the saturation of the specific color according to the area ratio of the specific color, as shown in FIGS. 7 to 9, characteristics when adjusting the saturation of the specific color according to the aperture value May be different.

  In the saturation adjustment amount characteristics in FIGS. 4 and 7 to 9, the portion for reducing the saturation is linear, but it may be nonlinear.

  The control unit 10 may change the threshold of the area ratio, the maximum reduction amount, and the upper limit value according to the focal length. The control unit 10 may change the threshold value of the area ratio, the maximum reduction amount, and the upper limit value depending on the position in the frame F. The control unit 10 may reduce the saturation more in a region near the end in the frame F. The controller 10 may reduce the saturation more in an out-of-focus area.

  When the imaging apparatus has a face detection function, the control unit 10 may not reduce the saturation in the face region or may reduce the degree of reduction.

7 Color detection unit 8 Threshold setting unit 9 Count unit 10 Control unit 11 Luminance detection unit 14 Color adjustment unit
Det1 first detector
Det2 Second detector

Claims (9)

A first detection unit that generates a first detection value corresponding to the area of a specific color corresponding to a false color included in each frame based on a video signal obtained by imaging a subject;
A color adjustment unit for adjusting the saturation of the video signal;
Based on the first detection value, when the ratio of the area of the specific color included in each frame is less than a predetermined threshold value, the color adjustment unit reduces the saturation of the specific color of the video signal A control unit for controlling
An imaging apparatus comprising:   The control unit is configured to change a reduction amount for reducing the saturation of the specific color in accordance with the ratio of the area of the specific color when the area ratio of the specific color is less than a predetermined threshold. The imaging device according to claim 1. A second detector for detecting whether each frame includes a high-luminance part having a predetermined luminance or higher based on the video signal;
When the second detection unit detects that each frame includes the high luminance portion, the control unit detects the video signal regardless of a ratio of the area of the specific color included in each frame. The imaging apparatus according to claim 1, wherein the color adjustment unit is controlled to reduce the saturation of the specific color by a preset maximum reduction amount.   The imaging device according to any one of claims 1 to 3, wherein the control unit changes the threshold value to a larger value as an aperture when imaging a subject approaches.   The control unit controls the color adjustment unit to change the maximum reduction amount of the saturation of the specific color to a reduction amount that is larger as the aperture when the subject is imaged is opened. Item 4. The imaging device according to any one of Items 1 to 3.   The control unit determines the saturation of the specific color when the ratio of the area of the specific color is equal to or greater than the threshold, and a constant upper limit value in which the amount of reduction in saturation increases as the aperture toward the subject is opened. The imaging apparatus according to claim 1, wherein the color adjustment unit is controlled to limit the color adjustment unit to the range.   The control unit reduces the saturation of the specific color over a first time when the area ratio of the specific color changes from the threshold value to less than the threshold value, and the area ratio of the specific color is The saturation of the specific color is increased over a second time shorter than the first time when the value changes from less than the threshold value to the threshold value or more. The imaging device according to item.   When the control unit changes from a frame that does not include the high luminance unit to a frame that includes the high luminance unit, the control unit reduces the saturation of the specific color over a first time, and includes the high luminance unit. When the frame changes from a frame to a frame that does not include the high-luminance portion, and the area ratio of the specific color is equal to or greater than the threshold, the color of the specific color is taken over a second time longer than the first time. The imaging apparatus according to claim 3, wherein the degree is increased. Imaging in a state where the saturation of a specific color corresponding to a false color in the video signal is reduced by a preset maximum reduction amount by a color adjustment unit that adjusts the saturation of the video signal obtained by imaging the subject. Start the device,
After activation of the imaging device, the detection unit generates a detection value according to the area of the specific color included in each frame of the video signal,
Based on the detection value, when the ratio of the area of the specific color included in each frame is less than a predetermined threshold, the color adjustment unit causes the color of the specific color according to the ratio of the area of the specific color. Reduce the degree,
Based on the detection value, when the ratio of the area of the specific color included in each frame is equal to or greater than the threshold, the degree of saturation adjustment of the specific color is determined by the color adjustment unit. A control method for an image pickup apparatus, characterized in that the upper limit value is set to a constant value regardless of the ratio of.

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