JP5402223B2 - Imaging device - Google Patents

Description

  The present invention relates to a technique used for an imaging apparatus such as a digital camera or a video camera that captures continuous images, and relates to a technique for suppressing an adverse effect on an image caused by an external flash or the like.

  As a conventional signal processing device (imaging device) that suppresses an adverse effect on an image due to an external flash or the like, for example, there is a device described in Patent Document 1. FIG. 9 is a block diagram of a conventional imaging apparatus 900. In Patent Document 1, a process for recording an image in a recording unit is described. Here, an example in which an image signal is externally output will be described.

  As shown in FIG. 9, the imaging apparatus 900 includes a CMOS sensor, a sensor driving circuit, and an analog / digital converter, which captures a continuous image and performs digital effective sequential with vertical effective 720 lines, horizontal effective 1280 pixels, and frame frequency 60 Hz. An imaging unit 950 that outputs a scanning image signal and an image processing unit 951 that performs gamma processing and contour enhancement on the output of the imaging unit 950 are provided. In addition, the imaging apparatus 900 compares the output of the imaging unit 950 with continuous frame images and detects the presence or absence of external flash, and the output signal (flash detection signal) of the flash detection unit 952. An output control unit 953 that performs switching control of whether the image signal output from the image processing unit 951 is output as it is or whether the accumulated image is output.

  FIG. 10 shows a block diagram of the output control unit 953 in the conventional imaging apparatus 900. The output control unit 953 includes, for example, the circuit shown in FIG.

  As shown in FIG. 10, the output control unit 953 is based on a memory circuit 954 that stores the image signal output from the image processing unit 951 for one frame, and an output signal (flash detection signal) of the flash detection unit 952. A switching circuit 955 that switches and outputs a signal output from the memory circuit 954 and an input signal from the image processing unit 951.

  The operation of the conventional imaging apparatus 900 configured as described above will be described.

  First, in the imaging unit 950, a drive signal is supplied from the sensor drive circuit to the CMOS sensor, and an optical signal (light from the subject) incident on the CMOS sensor is converted into an electrical signal by photoelectric conversion, and further acquired by photoelectric conversion. The electrical signal is converted into a digital progressive scanning image signal by analog / digital conversion. The digital progressive scanning image signal generated by the imaging unit 950 is output from the imaging unit 950. The digital progressive scanning image signal is supplied (output) to the image processing unit 951 and the flash detection unit 952.

  The image processing unit 951 performs gamma processing, contour enhancement processing, and the like on the input digital progressive scanning image signal, and the processed image signal is output to the output control unit 953.

  On the other hand, the flash detection unit 952 calculates an average luminance level for one frame with respect to the input digital progressive scanning image signal, and calculates the frame average luminance level of the input signal and the average luminance level of the previous frame. In comparison, when the average luminance level significantly increases, it is determined that the captured image is acquired by the imaging unit 950 in an environment where an external flash such as a flash exists. For example, when the frame average luminance level of the input signal increases by 100% or more with respect to the average luminance level of the previous frame, the flash detection unit 952 detects an external flash such as a flash (external flash exists). The flash detection signal is set to “1”, and the flash detection signal is output. When the external flash is not detected, the flash detection unit 952 sets the signal value of the flash detection signal to “0” and outputs a flash detection signal. The flash detection signal and the image signal output from the image processing unit 951 are input to the output control unit 953.

  In the output control unit 953, the image signal output from the image processing unit 951 is input to the memory circuit 954. The memory circuit 954 writes and stores one frame of the image signal, delays it by a time corresponding to one frame, and outputs the image signal. When the signal value of the flash detection signal output from the flash detection unit 952 is “1”, that is, when flash is detected, the memory circuit 954 does not write a new image signal and does not write the previous frame. The image signal of the same frame is repeatedly output. The switching circuit 955 switches between the image signal output from the image processing unit 951 and the image signal output from the memory circuit 954 based on the flash detection signal. When the signal value of the flash detection signal output from the flash detection unit 952 is “1”, that is, when the flash detection signal indicates that the flash is detected, the switching circuit 955 is switched from the memory circuit 954. When the output image signal is selected and output, and the signal value of the flash detection signal output from the flash detection unit 952 is “0”, that is, it indicates that the flash detection signal does not detect flash. In this case, the switching circuit 955 selects and outputs the image signal output from the image processing unit 951.

  Next, the operation of the imaging apparatus 900 will be described in detail with reference to FIG.

  FIG. 11 is a schematic diagram for explaining the adverse effect that an image (image captured by the image capture device 900) is subjected to by external flash in the conventional image capture device 900. FIG.

  (1) to (4) in FIG. 11 show continuous frames, and the timing at which the CMOS sensor receives light is shown on the basis of the vertical synchronization signal (the uppermost stage in FIG. 11).

  The “upper image” shown in FIG. 11 corresponds to an effective screen (a screen that is actually displayed when the image signal acquired by the imaging device is displayed on the display device (a screen excluding a portion such as a synchronization signal). It means the upper side of the screen. In the CMOS sensor, the first line of the effective screen receives light for the period indicated by the arrow in FIG. In the CMOS sensor, the light reception timing is slightly shifted for each line, so the 720th line is shifted by about 1/60 second with respect to the first line. Here, when there is an external flash at the timing indicated by the star in FIG. 11, the flash is received by the line constituting the lower screen of the frame (2) and the line constituting the upper screen of the frame (3). Will do. In such a situation, when the image signal acquired by the imaging unit 950 is displayed on the display device, a high-brightness horizontal band is generated over two consecutive frames on the display screen (video). The occurrence of this high-intensity horizontal band visually makes the user feel uncomfortable. Further, in a method of compressing using the correlation of consecutive frames, for example, in a process of compressing in the MPEG (Moving Picture Experts Group) method, block noise is generated when processing an image signal that generates the above-mentioned high luminance horizontal band. Or the compression rate is reduced.

  Therefore, in the conventional imaging device 900 shown in FIG. 9, when an external flash is detected, the image of the frame that received the flash is not output, but the image of the immediately preceding frame is output. For this reason, in the imaging apparatus 900, generation | occurrence | production of a high-intensity horizontal band can be prevented.

JP 2007-306225 A

  However, in the conventional imaging device, when an external flash is detected over two consecutive frames, an image of the same frame is output over three frames, and there is a problem that continuity is lost as a moving image.

  For example, in the case of FIG. 11, a high-intensity horizontal band is generated by an external flash in two frames (frame (2) and frame (3)). The image of (1)) is repeatedly output. That is, since the imaging device 900 outputs the same image (an image corresponding to the frame (1)) over three frames, when the image (video) acquired by the imaging device 900 is displayed on the display device, It will be displayed as a temporarily stationary image.

  The present invention solves the above-described conventional problems, and provides a high-performance imaging device that suppresses the adverse effects of a high-brightness horizontal band caused by an external flash and outputs an image that ensures continuity as a moving image. For the purpose.

  1st invention is an imaging device provided with a light quantity sensor part, an imaging part, a gain adjustment part, a drive part, and a gain control part.

  The light amount sensor unit detects a change in the amount of light due to an external flash. The imaging unit has an imaging element, converts an optical signal incident on the imaging element into an electrical signal, and acquires an image signal. The gain adjusting unit adjusts the gain of the image signal from the imaging unit. The drive unit generates drive pulses for the image sensor and sends timing information to the gain control unit. The gain control unit identifies the influence line of the external flash from the output of the light amount sensor unit and the drive timing, and outputs a gain control signal for controlling the gain of the image signal in units of lines.

  In this imaging device, the influence line of the external flash is specified and the gain of the line is controlled, so that the adverse effect of a high-brightness horizontal band image can be suppressed, and a plurality of the same frame images can be continuously displayed. Are not output. For this reason, when the image signal acquired by this imaging device is displayed on a display device, continuity as a moving image can be maintained.

  2nd invention is an imaging device provided with a light quantity sensor part, an imaging part, a gain adjustment part, a noise suppression part, a drive part, and a gain & noise suppression control part.

  The light amount sensor unit detects a change in the amount of light due to an external flash. The imaging unit has an imaging element, converts an optical signal incident on the imaging element into an electrical signal, and acquires an image signal. The gain adjusting unit adjusts the gain of the image signal from the imaging unit. The drive unit generates drive pulses for the image sensor and sends timing information to the gain and noise suppression control unit. The noise suppression unit performs noise suppression processing on the image signal after gain adjustment. For example, the noise suppression process indicates a process of checking the correlation with the upper, lower, left, and right pixels and averaging the pixels with the highest correlation. The gain & noise suppression control unit specifies the influence line of the external flash from the output of the light amount sensor unit and the drive timing, and outputs a control signal for controlling the gain of the image signal and the noise suppression degree in units of lines. That is, when the gain is lowered, the noise suppression degree is controlled to be small and the noise suppression effect is controlled to be small.

  As a result, the same effects as those of the first invention can be obtained, and further, a change in noise feeling due to variable gain can be suppressed, so that a more natural moving image can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device which can suppress the bad influence which becomes a high-intensity horizontal band by an external flash, and can output the image which ensured continuity as a moving image is realizable.

  Further, according to the present invention, it is possible to suppress the adverse effect of the external flash resulting in a high-brightness horizontal band, to ensure continuity as a moving image, and to output a more natural image with suppressed change in noise feeling. An imaging device that can be realized can be realized.

The block diagram of the imaging device 100 which concerns on 1st Embodiment. Block diagram of gain control unit 5 according to the first embodiment The schematic diagram explaining the mode of operation | movement when the external flash of the imaging device 100 which concerns on 1st Embodiment generate | occur | produces. The schematic diagram for demonstrating the correction effect when the external flash of the imaging device 100 which concerns on 1st Embodiment generate | occur | produces. The schematic diagram explaining the mode of operation | movement when the external flash of the imaging device 100 which concerns on 1st Embodiment generate | occur | produces in multiple times. The schematic diagram for demonstrating the correction effect when the external flash of the imaging device 100 which concerns on 1st Embodiment generate | occur | produces in multiple times. The block diagram of the imaging device 700 which concerns on 2nd Embodiment. The schematic diagram explaining the mode of operation | movement when the external flash of the imaging device 700 which concerns on 2nd Embodiment generate | occur | produces. Block diagram of a conventional imaging apparatus 900 Block diagram of output control unit 953 of conventional imaging apparatus 900 Schematic diagram for explaining the adverse effect of an image caused by external flash in the conventional imaging apparatus 900

  Hereinafter, embodiments will be described with reference to the drawings.

[First Embodiment]
<1.1: Configuration of Imaging Device>
FIG. 1 is a block diagram of an imaging apparatus 100 according to the first embodiment.

  As illustrated in FIG. 1, the imaging apparatus 100 includes a light amount sensor unit 6 that detects a change in light amount due to an external flash, an imaging unit 1 that converts light from a subject into an electrical signal, and an image output from the imaging unit 1. A gain adjustment unit 2 that adjusts the gain of the signal, a signal processing unit 3 that performs signal processing such as gamma correction and contour enhancement on the output signal from the gain adjustment unit 2, and a drive pulse for the imaging unit 1; Further, the influence line of the light quantity change due to the external flash or the like is identified from the drive part 4 for outputting the drive timing information to the gain control part 5 and the output and the drive timing of the light quantity sensor part 6, and the gain of the image signal is controlled in line units. A gain control unit 5 that outputs a gain control signal to be output.

  The imaging unit 1 includes a CMOS sensor (CMOS type image sensor (imaging device)) and an analog / digital conversion unit, converts light from a subject into an electrical signal by photoelectric conversion, and outputs a digital image signal as a gain adjustment unit. Output to 2. The imaging unit 1 captures continuous images and outputs, for example, a digital sequential scanning image signal having a vertical effective 720 lines, a horizontal effective 1280 pixels, and a frame frequency of 60 [Hz]. In this embodiment, the accumulation time (light reception time) in the CMOS sensor is set to 1/60 second, which is the same as one frame period determined by the frame frequency. That is, the imaging unit 1 performs charge accumulation over one frame period.

  The gain adjustment unit 2 linearly adjusts the delay adjustment of the image signal output from the imaging unit 1 and the overall gain, and is configured by a memory and a multiplier. The gain adjustment unit 2 is controlled by a gain control signal from the gain control unit 5. Is done. In the present embodiment, hereinafter, the gain in the signal processing of the gain adjusting unit 2 is referred to as a signal processing gain.

  The signal processing unit 3 performs gamma correction processing, contour enhancement processing, matrix processing, and the like, and shapes and outputs the image signal that matches the video standard.

  The drive unit 4 generates a pulse for driving the CMOS, supplies the pulse to the imaging unit 1, and outputs the current readout line number and accumulation time to the gain control unit 5 as drive timing information.

  The light quantity sensor unit 6 is composed of, for example, a sensor that outputs a voltage corresponding to the light quantity, and outputs a change in the light quantity due to an external flash or the like.

  The gain control unit 5 calculates the signal processing gain of the gain adjusting unit 2 for each line from the drive timing information from the driving unit 4 and the change in the external light amount from the light amount sensor unit 6, and outputs it as a signal processing gain control signal. .

  An example of a specific configuration of the gain control unit 5 is shown in FIG. As shown in FIG. 2, the gain control unit 5 includes a light amount information integration unit 50, an inverse number unit 51, a multiplication unit 52, and an output image gain generation unit 53.

  The light amount information integration unit 50 outputs the result of integrating the output of the light amount sensor unit 6 for a certain period, for example, the accumulation time, to the reciprocalization unit 51 and the output image gain generation unit 53 as light amount gain information. The light amount gain information is a ratio of the image level of the image signal affected by the external flash with respect to the image level of the image signal not affected by the external flash in the image signal output by the imaging unit 1 for each fixed period. (Details will be described later). The reciprocalization unit 51 calculates and outputs the reciprocal of the output from the light quantity information integration unit 50. The output image gain generation unit 53 generates a total gain waveform that is constant for each screen from the read line number that is drive timing information and the light amount gain information. The total gain is output by the gain adjusting unit 2 (based on the influence of the external flash) based on the image level of the image signal that is not affected by the external flash output from the imaging unit 1 (hereinafter referred to as a reference image level). The image level ratio of the image signal (including the image signal) is also shown. The total gain is obtained by adding the light amount gain information and the signal processing gain. The multiplier 52 multiplies the total gain waveform by the reciprocal of the light amount gain information, thereby calculating a signal processing gain control signal that makes the total gain constant for each screen with respect to the light amount that changes every moment ( Details will be described later).

<1.2: Operation of Imaging Device>
The operation of the imaging apparatus 100 configured as described above will be described. Here, a case where a CMOS sensor of a type in which the light receiving timing is slightly shifted for each line as a result of sequentially reading for each line will be described.

  First, the imaging unit 1 photoelectrically converts an optical signal incident on the CMOS sensor in accordance with a driving pulse from the driving unit 4, and further performs analog / digital conversion to output a digital sequential scanning image signal. Since the CMOS sensor sequentially outputs from the upper side of the screen and the light reception timing is slightly shifted for each line, the light reception timing is shifted by about 1/60 second between the first line and the 720th line.

  Considering the case where an external flash occurs, the image of the line read immediately after the time when the external flash occurs is brightened, and a dark image is output again from the line of the next frame.

  FIG. 3 is a schematic diagram for explaining the operation when an external flash is generated immediately before 360 lines are read.

  For example, it is assumed that an external flash is generated immediately before reading 360 lines of frame (2). Focusing on the immediately preceding 359th line, since the 359th line is already being read out, the external flash has an effect when reading the 359th line of the next frame. That is, a bright image is obtained at the 359th line of the next frame (3) after approximately 1/60 seconds. In the 360th line of the frame (2), an external flash is generated immediately before reading, so an image in which the external flash is received is output. That is, a bright image is obtained. In the 361st line of the frame (2), an external flash is generated slightly before reading, so that a bright image is similarly obtained. Since this is the same thereafter, the result is a bright image from the 360th line of the frame (2) to the 359th line of the next frame (3). Therefore, when frames (1) to (4) before and after the occurrence of the external flash are displayed by frame advance, the dark frame (1), the top 1 to 359 lines on the screen are dark, and the 360 to 720 lines on the bottom of the screen are bright. The frame (2), the upper 1 to 359 lines of the screen are bright, the lower 360 to 720 lines of the screen are dark (3), the entire frame is dark (4), and the frames (2) and (3) are bright horizontal bands Is generated.

  When an external flash occurs at the timing shown in FIG. 3, an image signal having a bright horizontal band in the frames (2) and (3) is output from the imaging unit 1 to the gain adjustment unit 2.

  The gain adjusting unit 2 adjusts the gain of the image according to the signal processing gain control signal from the gain control unit 5, corrects the horizontal band phenomenon of the frames (2) and (3), and outputs it to the signal processing unit 3.

  The signal processing gain control signal from the gain control unit 5 is obtained by multiplying a dark part by a high gain and a bright part by a low gain in order to suppress the horizontal band phenomenon of the frames (2) and (3). The total gain for each frame is made constant. Therefore, the gain adjustment unit 2 adjusts the gain in units of lines based on the signal processing gain control signal for the lateral band phenomenon when an external flash occurs, so that the total gain becomes a constant image level in units of frames. And output to the signal processing unit 3.

  In the drive unit 4, a drive pulse for driving the imaging unit 1 is generated and supplied to the imaging unit 1. At the same time, the drive timing information of the CMOS sensor is output to the gain controller 5.

  The light amount sensor unit 6 always measures the external light amount and outputs it as light amount information to the gain control unit 5. When an external flash or the like occurs, the light amount information changes greatly.

  The gain control unit 5 calculates a signal processing gain control signal for making the total gain in the frame unit constant.

  The horizontal band phenomenon of frames (2) and (3) is the amount of light received by lines 1 to 359 of frames (2) and (3) and the amount of light received by lines 360 to 720 of frames (2) and (3). Occurs because of the difference. Therefore, the signal processing gain control signal can be calculated from the reciprocal of the light amount gain information indicating the received light amount change and the total gain waveform in units of frames.

  Specifically, the gain control unit 5 acquires light amount information from the light amount sensor unit 6 and detects at which driving timing of the imaging unit 1 the light amount information is generated. Drive timing information such as a readout line number is acquired, light amount information is integrated and inversed, and a signal processing gain control signal for filling in a difference from an output image gain having a constant image level in units of frames is calculated.

  The state of the correction operation based on the operation of the gain control unit 5 will be described in detail with reference to FIGS.

  FIG. 2 is a block diagram illustrating an example of a specific configuration of the gain control unit 5.

  FIG. 3 is a schematic diagram for explaining the state of each control signal waveform when an external flash is generated immediately before 360 lines are read.

  FIG. 4 is a schematic diagram schematically showing an output image for explaining the effect of correction. In the figure, the light quantity information integration result corresponding to each line is shown alongside the output image of each frame.

  As shown in FIG. 3, it is assumed that an external flash occurs immediately before the 360th line of frame (2) is read.

  As shown in FIG. 3, the output of the imaging unit 1 becomes brighter from the 360th line of the frame (2) to the 359th line of the frame (3), which is a horizontal band phenomenon. The output of the light quantity sensor unit 6 is detected as a change that increases in an impulse manner when an external flash occurs, and is input to the gain control unit 5. The input light amount information is input to the light amount information integrating unit 50. The light quantity information integration unit 50 integrates the light quantity information input during the past fixed period (corresponding to the accumulation time) and outputs it as light quantity gain information. Here, when the light amount gain information in a certain period including the timing at which the external flash occurs is double the light amount gain information in the period without the external flash, as shown in the light amount information integration result of FIG. The output result is that the light amount is doubled from 360 lines in 2) to a certain period, that is, from 359 lines in frame (3). For the sake of convenience, the light amount gain information in the period without external flash will be described as 1, and the light amount gain information including the external flash will be described as 2.

  This light amount gain information indicates the amount of light received at the light receiving timing where each line is shifted, so that it is possible to obtain a constant total gain from frames (1) to (4) without the influence of the external flash. The gain adjustment may be performed using a reciprocal gain that cancels the light amount gain information.

  The output image gain generation unit 53 generates a total gain waveform of an ideal image that is to be obtained when an external flash occurs.

  For example, as an image after correction when an external flash occurs, when it is desired to make all the lines bright in the same manner as the horizontal line only in the frame where the horizontal band phenomenon occurs, the frame as shown in the total gain waveform of FIG. The total gain of (2) and the entire frame (3) may be an image that is 2.0 times equivalent to the light amount gain information of the portion affected by the external flash. The output image gain generation unit 53 generates the total gain waveform from the light amount gain information and the drive timing information.

  Finally, the gain adjusted by the gain adjusting unit 2 is multiplied by the reciprocal of the light amount gain information and the total gain so that the image level of the image signal output from the gain adjusting unit 2 with respect to the reference image level becomes the total gain. Therefore, the result of multiplication by the multiplication unit 52 is output as a signal processing gain control signal.

  When the gain adjustment unit 2 performs gain adjustment using the signal processing gain control signal calculated in this way, the image of the lateral band phenomenon caused by the external flash can be corrected to an image having a constant total gain for each frame. it can. That is, as shown in FIG. 4, the image before correction is an image with a white horizontal band in frames (2) and (3), but the image after correction is frames (2) and frames (2). In (3), when the total gain of the portion other than the horizontal band is set to 2.0 times, the total gain of the entire frame becomes constant, and the image has no horizontal band disturbance and is temporally continuous. A natural image output can be obtained.

  Further, the case where the external flash is performed a plurality of times (twice) will be described with reference to FIGS.

  FIG. 5 is a schematic diagram for explaining the state of each control signal waveform when external flash occurs twice just before reading out 360 lines and 540 lines.

  FIG. 6 is a schematic diagram schematically showing an output image for explaining the effect of correction when an external flash occurs twice.

  As shown in FIG. 5, the first external flash (1) (small amount of light) just before the 360th line of frame (2) is read and the second external flash (2) (just before the 540th line is read). Suppose that a large amount of light is generated.

  As shown in FIGS. 5 and 6, the output of the imaging unit 1 is doubled from the 360 line to the 539 line of the frame (2) due to the external flash (1), and is 540 lines of the frame (2). From frame (3) to 359 lines, the effect of external flashes (1) and (2) is four times brighter, and from frame (3) is 360 to 539 lines, the effect of external flashes (2) is tripled. The image becomes a plurality of horizontal band images before correction.

  Similarly, the output of the light amount sensor unit 6 is detected to change so as to increase in an impulse manner when an external flash is generated, and is input to the gain control unit 5. The input light amount information is input to the light amount information integration unit 50, integrated for a predetermined time (accumulation time), and output as light amount gain information. As a result of the integration, if the light amount gain information is doubled, four times, or three times that when there is no external flash, as shown in the light amount gain information of FIG. The output result is 4 times from 540 lines of frame (2) to 359 lines of frame (3) and 3 times from 360 lines to 539 lines of frame (3).

  Since this light amount gain information indicates the amount of light received at the light receiving timing where each line is shifted, similarly, a constant total gain from frame (1) to (4) can be obtained without the influence of external flash. In order to achieve this, the gain may be adjusted using a reciprocal gain that cancels the light amount gain information.

  The output image gain generation unit 53 generates a total gain waveform of an ideal image that is to be obtained when an external flash occurs.

  Similarly, as an image after correction when an external flash occurs, when making a bright image similar to the horizontal line affected only by the external flash (1) in all the lines where the horizontal band phenomenon occurs, As shown in the total gain of FIG. 5, the frame (2) and the frame (3) are images that are 2.0 times larger, and are generated by the output image gain generation unit 53 from the light amount gain information and the drive timing information.

  The gain to be adjusted to the image signal based on the light amount gain information affected by the external flash so as to finally become the total gain is obtained by multiplying the reciprocal number of the light amount gain information by the total gain, so that the multiplying unit 52 The result of multiplication by is output as a signal processing gain control signal.

That is, as shown in the signal processing gain control signal of FIG.
1.0 times-> 2.0 times-> 1.0 times-> 1/2 times-> 2/3 times-> 2.0 times-> 1.0 times signal processing gain control signal, gain adjustment by gain adjustment unit 2 By performing the above, it is possible to correct the image of the horizontal band phenomenon caused by the external flash to an image having a constant total gain in units of frames. That is, as shown in FIG. 6, the image before correction is an image having a plurality of white horizontal bands in the frame (2) and the frame (3), but the image after correction is the frame (2). In addition, it is possible to obtain a natural image output in which temporal continuity is ensured with an image having no horizontal band interference in which the total gain of the frame (3) is constant 2.0 times.

  In addition, even when a plurality of more complicated external flashes occur, similarly, the effect of suppressing the adverse effect of a plurality of high-brightness horizontal bands and obtaining a natural image output that ensures continuity as a moving image. Demonstrate.

  As described above, the imaging apparatus 100 according to the present embodiment realizes an imaging apparatus that can suppress an adverse effect of a high-brightness horizontal band due to an external flash and can output an image that ensures continuity as a moving image. be able to.

  In addition, the imaging apparatus 100 according to the present embodiment realizes an imaging apparatus that can suppress the adverse effect of a plurality of high-intensity horizontal bands due to a plurality of external flashes and can output an image that ensures continuity as a moving image. be able to.

  In the above description, the total gain in the frame (2) and the frame (3) of the output image gain generation unit 53 is 2.0 times the same as the light amount gain information. However, the total gain is constant for each frame. Any value may be used as long as it is fixed in advance, a value determined by a menu or the like, or a value calculated from light amount gain information. The value calculated from the light amount gain information may be, for example, a value obtained by averaging the increase in the light amount gain information. That is, in the case of FIG. 3, since the light amount gain information is increased from 1.0 times to 2.0 times, the increase is averaged and determined to be 1.5 times. Therefore, the dark portion (1.0 times) and the bright portion (2.0 times) of frame (2) and frame (3) are corrected to be constant at the intermediate level (1.5 times). Become.

  In the above description, the corrected bright frame is two frames (2) and (3). However, the present invention is not limited to this. For example, only the frame (2) may be a bright frame. The frames (1) to (4) may remain dark. It is obvious that all of these can be realized by adjusting the total gain waveform in the output image gain generation unit 53.

  In addition, the gain control signal may be a signal obtained by further performing processing such as LPF on the output of the multiplier 52.

[Second Embodiment]
<2.1: Configuration of imaging apparatus>
FIG. 7 is a block diagram of an imaging apparatus 700 according to the second embodiment.

  The imaging apparatus according to the second embodiment includes a noise suppression unit 7 added to the imaging apparatus 100 according to the first embodiment, and a gain & noise suppression control unit 8 that controls the gain control unit 5 in conjunction with gain and noise suppression. The configuration is changed to

  That is, as illustrated in FIG. 7, the imaging apparatus 700 is output from the light amount sensor unit 6 that detects a change in the amount of light due to an external flash, the imaging unit 1 that converts light from a subject into an electrical signal, and the imaging unit 1. A gain adjusting unit 2 that adjusts the gain of the image signal, a noise suppressing unit 7 that performs noise suppression processing on the output signal from the gain adjusting unit 2, gamma correction, contour enhancement, and the like on the output signal from the noise suppressing unit 7 The signal processing unit 3 that performs the signal processing, the drive unit 4 that generates the drive pulse of the imaging unit 1, and outputs the drive timing information to the gain & noise suppression control unit 8, and the output and drive of the light amount sensor unit 6 A gain & noise suppression control unit 8 that identifies an influence line of a light amount change caused by an external flash from the timing and controls the gain of the image signal and the noise suppression level in units of lines; .

  The noise suppression unit 7 may be any noise suppression circuit as long as the noise suppression degree can be adjusted. The gain & noise suppression control unit 8 is configured to output two systems of signals created with the same configuration as the gain control unit 5 as a gain control signal and a noise suppression control signal.

  Except for the noise suppression unit 7 and the gain & noise suppression control unit 8, the configuration is the same as that of the imaging apparatus 100 according to the first embodiment.

<2.2: Operation of Imaging Device>
An operation of the imaging apparatus according to the second embodiment configured as described above will be described.

  FIG. 8 is a schematic diagram for explaining the state of each control signal waveform when an external flash is generated just before reading 360 lines. The schematic diagram in the first embodiment (FIG. 3) shows the same waveform as the gain control signal. A noise suppression control signal has been added.

  Similar to the operation of the first embodiment, a gain control signal waveform is generated, and a control signal having the same waveform is also output as a noise suppression control signal, so that noise suppression is strongly controlled for a line with high gain control. To.

  The remarkable operation feature of the imaging apparatus 700 according to the second embodiment is that, in addition to the gain control similar to that in the first embodiment, a control for greatly increasing noise suppression is simultaneously performed on a line with a large gain increase. It is. That is, the noise suppression control signal generated in the same manner as the signal processing gain control signal is output to the noise suppression unit 7 to control the noise suppression effect. The line whose gain has been greatly increased is also amplified in noise at the same time, but is controlled so as to strongly suppress noise by the noise suppression unit 7 in the subsequent stage. This suppresses the uncomfortable feeling of the output image due to the gain change in the same frame.

  As described above, in the imaging apparatus 700 according to the present embodiment, the adverse effect of a high-brightness horizontal band caused by external flash light is suppressed, continuity is ensured as a moving image, and changes in the noise feeling of the same frame are suppressed. Thus, an imaging device capable of outputting a more natural image can be realized.

  The noise suppression unit 7 may be any noise suppression circuit as long as the noise suppression degree can be adjusted.

  In addition, although the noise suppression unit 7 has been described as being disposed immediately after the gain adjustment unit 2, the noise suppression unit 7 may be disposed in the signal processing unit 3.

  In addition, the signal processing gain control signal and the noise suppression control signal are output to the two systems of the signal processing gain control signal and the noise suppression control signal as the control signal created by the configuration of the gain control unit 5 of the first embodiment. However, it may be output after further processing such as a gain control signal LPF and a noise suppression control signal LPG.

  The image pickup apparatus according to the present invention can output a high-brightness horizontal band caused by an external flash, and can output an image that ensures continuity as a moving image. It is also very useful.

DESCRIPTION OF SYMBOLS 1,950 Image pick-up part 2 Gain adjustment part 3 Signal processing part 4 Drive part 5 Gain control part 6 Light quantity sensor part 7 Noise suppression part 8 Gain & noise suppression control part 50 Light quantity information integration part 51 Inverse part 52 Multiplication part 53 Output image Gain generation unit 100, 700, 900 Imaging device 951 Image processing unit 952 Flash detection unit 953 Output control unit 954 Memory circuit 955 Switching circuit

Claims (5)

A light quantity sensor for detecting a change in light quantity;
An imaging unit that outputs an imaging signal of a subject;
A gain adjustment unit for adjusting the gain of the imaging signal;
A drive unit that drives the imaging unit and outputs the drive timing ;
A gain control unit for controlling the gain of the gain adjustment unit,
Wherein the gain control unit, and an output and the drive timing of the light amount sensor unit, to identify the impact line of the external flash, the imaging device and controls the gain based on the specified the affected lines. Wherein the gain control unit, an imaging apparatus according to claim 1, wherein the determining the gain based on the amount of light detected by the light amount sensor unit to the reciprocal of the predetermined period integration value. Wherein the gain controller includes a preset value, to claim 1, characterized by using the result of multiplying the inverse number of the light intensity sensor fixed period cumulative value of the detected light amount by the unit as a control gain The imaging device described. A light quantity sensor for detecting a change in light quantity;
An imaging unit that outputs an imaging signal of a subject;
A gain adjustment unit for adjusting the gain of the imaging signal;
A noise suppression unit that performs signal processing to suppress noise of the imaging signal;
A drive unit that drives the imaging unit and outputs the drive timing ;
A gain and noise suppression control unit that controls the gain of the gain adjustment unit and the noise suppression degree of the noise suppression unit;
The gain & noise suppression control unit, characterized in that from the output and the drive timing of the light amount sensor unit, to identify the impact line of the external flash, controls the gain and noise suppression based on the identified the affected line An imaging device. The image pickup apparatus according to claim 4, wherein the gain & noise suppression control unit outputs a control signal that performs stronger noise suppression as the gain increases.