WO2019058980A1 - Imaging device - Google Patents

Imaging device Download PDF

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Publication number
WO2019058980A1
WO2019058980A1 PCT/JP2018/032987 JP2018032987W WO2019058980A1 WO 2019058980 A1 WO2019058980 A1 WO 2019058980A1 JP 2018032987 W JP2018032987 W JP 2018032987W WO 2019058980 A1 WO2019058980 A1 WO 2019058980A1
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Prior art keywords
signal
pixel
contour correction
imaging device
video signal
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PCT/JP2018/032987
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French (fr)
Japanese (ja)
Inventor
中村　和彦
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株式会社日立国際電気
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Priority to JP2019543544A priority Critical patent/JP6827121B2/en
Publication of WO2019058980A1 publication Critical patent/WO2019058980A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/10—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths
    • H04N23/13—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from different wavelengths with multiple sensors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/60—Control of cameras or camera modules
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/14—Picture signal circuitry for video frequency region
    • H04N5/20—Circuitry for controlling amplitude response
    • H04N5/205—Circuitry for controlling amplitude response for correcting amplitude versus frequency characteristic
    • H04N5/208—Circuitry for controlling amplitude response for correcting amplitude versus frequency characteristic for compensating for attenuation of high frequency components, e.g. crispening, aperture distortion correction

Definitions

  • the present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus capable of outputting a video signal with an improved degree of modulation at low frequencies by performing contour correction that does not include high frequency components.
  • HDTV High Definition Te leVision: high-definition television
  • HDTV camera with recording unit HDTV (1080 ⁇ 1920) camera with Internet Protocol (hereinafter IP) transmission unit
  • IP Internet Protocol
  • higher-definition 4K (2160 ⁇ 3840) camera 8K (high-definition television) 4320 ⁇ 7680) Cameras and the like have been commercialized, and non-compression recording apparatuses using HDDs (Hard Disk Drives) have also been commercialized.
  • FIG. 6 is a cross-sectional explanatory view showing the configuration of the imaging device, where (a) is a CCD sensor (imaging device), (b) is a conventional CMOS sensor (surface-illuminated CMOS imaging device), (c) is BSI ( The back side illumination) type CMOS sensor (back side illumination type CMOS image sensor) is shown.
  • a microlens 91, a color filter 92, and a photodiode 93 are stacked, and a metal wiring layer 94 is formed between the photodiode 93 and the color filter 92. ing.
  • Incident light collected by the micro lens 91 passes through the color filter 92, is separated into R (red), G (green) and B (blue) components, and is incident on the photodiode 93 to generate charge. Are transferred in the vertical direction and the horizontal direction to be converted into a voltage for each pixel.
  • the CCD sensor has high sensitivity, it consumes a large amount of power and is difficult to integrate peripheral circuits as compared to a CMOS image sensor.
  • the surface-illuminated CMOS imaging device shown in FIG. 6B has a configuration in which a transistor or the like is provided for each pixel, and although low power consumption and easy integration are possible, sensitivity is low.
  • the metal wiring layer 93 is provided on the backside of the photodiode 93, so that it is highly sensitive, low power consumption, and easy to integrate.
  • CMOS imaging device 4/3 or less including 8K, 1.25 type, 2/3 or less at 4K
  • CMOS imaging device 4/3 or less including 8K, 1.25 type, 2/3 or less at 4K
  • the metal wiring layer 94 is stacked between the first and second microlenses (on-chip lenses) 91, the degree of modulation in the low region is low.
  • an optical low pass filter O-LPF; Optical Low Pass Filter
  • O-LPF Optical Low Pass Filter
  • the pixel pitch of the image pickup element is about 2.5 ⁇ m and about 4.5 times the green wavelength 0.55 ⁇ m, and the aberration of the high magnification zoom lens is optically It can not be corrected, and the degree of modulation at low frequencies (Modulation transfer function characteristics: MTF; Modulation Transfer Function ) Decreases.
  • FIG. 7 is an explanatory view showing the relationship between the aperture value and the modulation degree. It is known that, even with an ideal lens having no aberration, the degree of modulation decreases due to optical diffraction at a green central wavelength of 0.55 ⁇ m when the number of wavelengths of the pixel pitch is reduced to a number equal to or greater than the wavelength.
  • a blurred image with a pixel pitch of approximately F5 and a 400 TV line with a modulation degree of 50% or less with an F5 pixel wavelength of 4.9 wavelengths is 2/3 ⁇ 4K (2160 ⁇
  • an blurred image with a modulation degree of 50% or less is obtained even at 800 TV with about F4.8.
  • the modulation degree is around F4 for HDTV (1080 ⁇ 1920) cameras, around F2.8 for 4K (2160 ⁇ 3840) cameras, and around F2 for 8K (4320 ⁇ 7680) cameras.
  • the degree of modulation decreases in the vicinity of the aperture opening due to aberration, and the degree of modulation decreases in the vicinity of the stop due to optical diffraction.
  • Patent Document 1 describes an edge enhancement processing apparatus for passing an edge correction signal through a low pass filter (LPF; Low Pass Filter) in order to attenuate signal components and noise components around half the sampling frequency fs.
  • LPF Low Pass Filter
  • Patent Document 2 describes an imaging device that reduces the contour correction frequency when the degree of modulation decreases at telephoto.
  • Patent Document 3 describes that edge enhancement (edge correction of a difference between pixel intervals in units of 2 or 4) is performed from a delay corresponding to a power of 2 of the basic processing rate.
  • Patent Document 4 describes an imaging device that reduces the center frequency of contour correction when the aperture value is large and the degree of modulation is reduced by optical diffraction.
  • the present invention has been made in view of the above circumstances, and in an imaging apparatus using a surface-illuminated CMOS imaging device having a pixel pitch of 5 wavelengths or less, the MTF at low frequencies is improved and focusing is easy even at the telephoto end. It is an object of the present invention to provide an imaging device that can
  • the present invention for solving the problems of the above-described conventional example is an imaging apparatus using a CMOS imaging device whose pixel pitch is five times or less of the central wavelength of imaging light, and comprises an imaging device and color input light A color separation unit that separates each time and outputs a video signal, and a video signal of a correction target pixel to which contour correction is applied to the video signal from the color separation unit, and a pixel interval of a power of 2 from the correction target pixel.
  • the difference with the video signal of the plurality of pixels is calculated, the contour correction signal is generated based on the difference addition signal obtained by adding the plurality of differences, the contour correction signal is added to the video signal of the correction target pixel, and the contour correction is performed.
  • a contour correction unit for performing the processing.
  • the outline correction unit calculates a difference between the video signal of the pixel to be corrected and the video signal of a plurality of pixels having a pixel interval of a power of 2 from the pixel to be corrected.
  • a difference addition unit that adds the plurality of differences to generate a difference addition signal; and adjusting the difference addition signal based on the video signal level of the pixel to be corrected; and an edge correction signal corresponding to the pixel to be corrected It is characterized in that it comprises: a contour correction signal generation unit to be generated; and a contour correction signal addition unit to add a contour correction signal to a video signal of a pixel to be corrected.
  • the present invention is characterized in that, in the above-mentioned imaging device, the pixel interval of the power of 2 is from 2 pixel interval to 32 pixel interval.
  • the present invention is characterized in that, in the above-described imaging device, the imaging device is a surface-illuminated CMOS imaging device.
  • contour correction is performed on a video signal input from a lens whose open aperture value at the telephoto end is larger than the pixel pitch of the imaging device / center wavelength or a lens with large aberration. It is characterized.
  • an imaging device using a CMOS imaging device having a pixel pitch equal to or less than five times the central wavelength of imaging light comprising an imaging device, separating input light for each color and outputting a video signal A color separation unit, a video signal of a correction target pixel to which contour correction is applied to a video signal from the color separation unit, and a video signal of a plurality of pixels having a pixel interval of a power of 2 from the correction target pixel
  • a contour correction unit that calculates a difference, generates an edge correction signal based on a difference addition signal obtained by adding the plurality of differences, and adds an edge correction signal to a video signal of a correction target pixel to perform edge correction Since the imaging apparatus is used, a contour correction signal containing no high frequency component is generated to emphasize the low band contour correction signal, improve the modulation degree in the low band, and focus at the telephoto end with a shallow depth of field. Can be facilitated There is a result.
  • the contour correction unit calculates the difference between the video signal of the pixel to be corrected and the video signal of a plurality of pixels having a pixel interval of a power of 2 from the pixel to be corrected
  • a difference addition unit that generates a difference addition signal by adding the differences of the above, and an outline that adjusts the difference addition signal based on the video signal level of the pixel to be corrected to generate an edge correction signal corresponding to the pixel to be corrected Since the imaging apparatus includes the correction signal generation unit and the contour correction signal addition unit that adds the contour correction signal to the video signal of the pixel to be corrected, the difference addition signal is appropriately adjusted to generate the contour correction signal. There is an effect that the degree of modulation in the low band can be improved.
  • the image pickup apparatus since the image pickup apparatus has the pixel interval of power of 2 from 2 pixel interval to 32 pixel interval, the modulation degree of 1.05 MHz of HDTV of 2K jump operation is improved.
  • the degree of modulation at 27.5 MHz, which is based on 1 MHz, can be relatively lowered, and the degree of modulation in the low band can be sufficiently improved without increasing the circuit scale too much.
  • the imaging device is configured as the surface-illuminated CMOS imaging device according to the present invention, there is an effect that it is possible to realize an imaging device with improved low-frequency modulation at low cost.
  • the image pickup apparatus performs the contour correction on a video signal input from a lens whose open aperture value at the telephoto end is larger than the pixel pitch of the image pickup element / center wavelength or a lens having large aberration. Therefore, it is possible to improve the degree of modulation at low cost and to facilitate focusing at the telephoto end without using an expensive and large UHDTV lens.
  • An image pickup apparatus is an image pickup apparatus using a CMOS image pickup element having a pixel pitch of 5 wavelengths or less of a central wavelength of image pickup light.
  • the difference between the target pixel and the video signal of the plurality of pixels which is the pixel interval of the power of 2 is calculated, and the contour correction signal is generated based on the difference addition signal obtained by adding the plurality of differences. Since the contour correction signal is added to the signal, the contour correction signal without high frequency components near fs / 2 can be obtained, and the low frequency contour correction signal is reinforced to improve the MTF in the low frequency region. Also, focusing can be facilitated at the telephoto end of the telephoto lens.
  • FIG. 1 is a configuration block diagram showing a schematic configuration of the present imaging device.
  • the imaging device 1 includes a color separation optical system 2, an imaging device 3 (3 R, 3 G, 3 B), a video signal processing unit 4, and a parallel / serial (P / S) conversion unit 5.
  • the CPU Central Processing Unit
  • the lens 7 and the view finder image display device 8.
  • the color separation optical system 2 separates the incident light from the lens 7 into red (R), green (G) and blue (B).
  • the image pickup device 3 is a CMOS image pickup device, the image pickup device 3R photoelectrically converts red light, the image pickup device 3G photoelectrically converts green light, and the image pickup device 3B photoelectrically converts blue light. Generates a charge according to the Here, the pixels of the imaging device 3 are arranged at a pixel pitch of 5 wavelengths or less based on the wavelength (0.55 ⁇ m) of green light.
  • the color separation optical system 2 and the imaging device 3 correspond to a color separation unit described in the claims.
  • the video signal processing unit 4 includes a contour correction unit 11, a gamma color correction unit 12, and a matrix unit 13, and is configured by an FPGA with a large capacity memory, an external FPGA with DDR (Double-Data-Rate) memory, etc. Ru.
  • the contour correction unit 11 is a characteristic portion of the present imaging device, and performs contour correction processing for correcting the contour of the image for each of the red, green, and blue color components.
  • the contour correction unit 11 includes a direct contour correction unit that performs vertical contour correction processing, and a horizontal contour correction processing unit that performs horizontal contour correction processing.
  • the contour correction unit 11 generates an image of a pixel to be corrected and an image of a pixel having a pixel interval of a power of 2 (for example, an interval of 2, 4, 8, 16, 32 pixels) A contour correction signal is generated based on the sum of the difference with the signal.
  • a contour correction unit 11 will be described later.
  • the gamma color correction unit 12 performs processing of correcting the gradation of the image (gamma color correction).
  • the matrix unit 13 performs processing to adjust the luminance and color of the video.
  • the parallel / serial converter 5 converts parallel data into serial data and outputs the serial data to the outside.
  • the CPU 6 controls the entire image pickup apparatus, and in particular, controls the contour correction unit 11 to realize appropriate contour correction. Further, the CPU 6 controls the level of the contour correction signal in accordance with the lens aperture value.
  • the operation of the present imaging device will be briefly described.
  • the light input from the lens 7 is separated into red, green, and blue components in the color separation optical system 2, and is photoelectrically converted by the imaging elements 3R, 3G, and 3B, respectively, to form an electric signal.
  • the signal of each color is subjected to vertical contour correction and horizontal contour correction processing in the contour correction unit 11, gamma color correction is performed in the gamma color correction unit 12, color adjustment is performed in the matrix unit 13, and the parallel correction is performed.
  • the serial data is converted into serial data by the / serial converter 5 and output to the outside as a video signal.
  • FIG. 2 is a block diagram of the vertical contour correction unit of the present imaging device.
  • the vertical contour correction unit 11 corrects the contour in the vertical direction by comparing video signals between pixels arranged in the vertical direction.
  • the vertical contour correction unit includes a plurality of line memory units M20 to M29, a plurality of negative multipliers N20 to N24 and N26 to N30, a positive multiplier P25, and a plurality of adders 20.
  • the line memory units M20 to M29, the negative multipliers N20 to N24 and N26 to N30, the positive multiplier P25, and the plurality of adders 20 to 29 correspond to the difference addition unit described in the claims.
  • the video level determination unit 28 and the multipliers 29 and 32 correspond to the contour correction signal generation unit.
  • the line memory unit includes an image signal of a line (referred to as 32H) to be corrected and an image of a line separated by 2, 4, 8, 16 and 32 pixels in the vertical direction from the line to be corrected which is a characteristic portion of the apparatus. A necessary video signal is held and output in order to obtain a difference from the signal.
  • the line memory unit M20 stores video signals of 16 lines
  • the line memory unit M21 stores video signals of 8 lines
  • the line memory unit M22 stores video signals of 4 lines
  • the line memory unit M23 accumulates video signals for two lines, and outputs one line each to negative multipliers N21 to N24.
  • the line memory unit M24 holds the line to be corrected (32H) and the next line (31H), and sends the line to be corrected to the positive multiplier P25, the video level judgment unit 28, and the outline correction signal addition unit 33. Output.
  • Line memory units M25 and M26 store video signals for two lines
  • line memory unit M27 stores video signals for four lines
  • line memory unit M28 stores video signals for eight lines.
  • the line memory unit M29 accumulates video signals of 16 lines, and outputs the video signals to negative multipliers N26 to N30, respectively, one line at a time.
  • the negative multipliers N21 to N24 multiply the video signals output from the line memory units M20 to M23 by negative coefficients, and output the result to the adders 21 to 24.
  • Negative multipliers N26 to N30 multiply the video signals output from the line memory units M25 to M29 by negative coefficients, and output the result to the adders 26 to 29.
  • the negative multiplier N20 multiplies the signal before correction by a negative coefficient, and outputs the result to the adder 20.
  • the positive multiplier P25 multiplies the video signal of the correction target line (32H) output from the line memory M24 by a positive coefficient.
  • the adders 20 to 29 add the outputs of the negative multipliers N20 to N24 and N26 to N30 and the positive multiplier P25, and output a difference addition signal from the adder 20.
  • the adders 20 to 29 correspond to the difference addition unit in the claims.
  • the coefficient of positive multiplier P25 or / and the negative multiplier such that the sum of the difference between the output from each negative multiplier and the output from positive multiplier P25 is calculated in adder 20.
  • the coefficients of N20 to N24 and N26 to N30 are adjusted in accordance with an instruction from the CPU 6.
  • the difference addition signal output from the adder 20 is separated from the correction target line (32H) by the power of two (here, 2, 4, 8, 16, 32) from the correction target line. It is the sum of the difference with the video signal of the line.
  • the difference signal output from the adder 20 is separated from the correction target line (32H) by the power of two (here, 2, 4, 8, 16, 32) from the correction target line. It is the sum of the difference with the video signal of the line.
  • the video level determination unit 28 determines the level of the video signal of the correction target line, and detects a dark portion by threshold determination.
  • the multiplier 29 variably adjusts the positive / negative and amplification degree in order to attenuate the outline correction signal of the dark part. In the region where the video level is low, the video level determination unit 28 and the multiplier 29 perform control to reduce the contour correction signal in order to reduce noise due to addition of the contour correction signal. Control is performed to keep the level of the contour correction signal constant.
  • the CPU 6 controls the coefficients of each of the negative multipliers N20 to N24 and N26 to N30 and the positive multiplier P25, and controls the positive and negative values of the amplification value to be multiplied by the multiplier 29 and the amplification degree. Specifically, the CPU 6 outputs only the video signal of the correction target line (32H) and the power of 2 from the correction target line (here, 2, 4, 8, 16, 32) from the adder 20 The coefficients are controlled so as to be the sum of the difference from the video signal of the distant line. Further, the CPU 6 of the present imaging device controls the level of the contour correction signal according to the lens aperture value in order to improve the deterioration of the degree of modulation of the video signal when the lens aperture is narrowed. Specifically, when the lens iris is on the aperture side, the coefficient of the multiplier 29 is adjusted to control to amplify the contour correction signal.
  • a small amplitude / large amplitude compression limiter (hereinafter referred to as a limiter) 31 compresses if the differential addition signal has a large amplitude, and limits the compression if the differential addition signal has a small amplitude.
  • Multiplier 32 multiplies the output from limiter 31 by the coefficient from multiplier 29 to produce a vertical contour correction signal of appropriate polarity and level.
  • the correction signal addition unit 33 performs vertical contour correction by adding the vertical contour correction signal to the correction target line (32H) output from the line memory unit M24.
  • the modulation degree of the ultra low band can be enhanced, and the high band modulation degree is relatively decreased.
  • 5 MHz modulation degree defined as 100% of 0.5 MHz of National Television System Committee (NTSC) or 27.5 MHz defined as 100% of 1 MHz of 2 K transit scan HDTV
  • the high frequency modulation degree such as the modulation degree is relatively reduced.
  • FIG. 2 The operation of the vertical contour correction unit of the present imaging device will be described with reference to FIG.
  • the pre-correction signal is input to the negative multiplier N20 and the line memory unit M20, and is stored at the timing of the clock in the line memory units M20 to M29, and the negative multipliers N21 to N30 and the positive multiplication are added line by line. Is output to the receiver P25.
  • the correction target line output from the line memory unit M24 is 32H
  • 0H, 16H, 24H, and 30H are input to the negative multipliers N20 to N24, respectively
  • the positive multiplier P25 is input to the negative multipliers N20 to N24
  • H32 is input to the negative multipliers N26 to N30
  • 34H, 36H, 40H, 48H and 64H are input to the negative multipliers N26 to N30, respectively. That is, the video signal of a line separated by a power of 2 from the correction target line is input to the negative multipliers N21 to N24 and N26 to N30.
  • each of the negative multipliers N20 to N24 and N26 to N30 and the positive multiplier P25 are multiplied by a negative or positive coefficient, added by the adders 20 to 29, and the video signal of the correction target line and the other lines
  • the sum of the differences with the video signal of the above is calculated, and is output from the adder 20 as a difference addition signal.
  • the differential addition signal is subjected to amplitude adjustment by the limiter 31 and further adjusted according to the video level by the multiplier 32 to generate a vertical contour correction signal, and the correction signal addition unit 33 generates the correction target line.
  • the video signal and the vertical contour correction signal are added to perform contour correction in the vertical direction. In this manner, the operation of the vertical contour correction unit is performed.
  • the vertical contour correction signal is generated based on the sum of the differences up to the 32 pixel interval in the vertical direction, but the sum of the differences of the 64 pixel interval and the 128 pixel interval is calculated A vertical contour correction signal may be generated.
  • FIG. 3 is a configuration diagram of a horizontal contour correction unit of the present imaging device.
  • the horizontal contour correction unit corrects the horizontal contour by comparing video signals between pixels arranged in the horizontal direction.
  • the horizontal contour correction unit includes a plurality of pixel delay units D40 to D49, a plurality of negative multipliers N40 to N44 and N46 to N50, a positive multiplier P45, and a plurality of adders 40.
  • the horizontal contour correction unit is provided with pixel delay units D40 to D49 instead of the line memory units M20 to M29 of the vertical contour correction unit shown in FIG. 2, and performs processing on pixels arranged in the horizontal direction.
  • the other basic configuration and operation are the same as those of the vertical contour correction unit, and therefore detailed description will be omitted.
  • the horizontal contour correction unit the sum of the difference between the video signal of the correction target pixel and the video signal of the pixel separated by 2, 4, 8, 16, 32 pixels in the horizontal direction from the correction target pixel is the adder 40.
  • the signal is output as an addition difference signal from the above, and amplitude correction of the addition difference signal is performed in the small amplitude / large amplitude compression limiter 53, and is adjusted by the multiplier 54 based on the determination result in the video level determination unit 51 to correct horizontal contour.
  • a signal is generated, and the video signal of the correction target pixel (32d) and the horizontal contour correction signal are added in the correction signal addition unit 55 to perform contour correction in the horizontal direction.
  • peripheral pixel difference processing of one pixel interval is not performed, so that the modulation factor of the ultra low band can be enhanced, and the high band modulation factor is relatively lowered.
  • FIG. 4 is a frequency axis display of differential addition signals at intervals of 2, 4, 8, and 16 pixels.
  • coefficients other than 0 are set in the positive multiplier P25 and the negative multipliers N24 and N26.
  • the other negative multiplier is a differential addition signal obtained from the adder 40 with the coefficient 0 set.
  • the differential addition signal of 4-pixel intervals shown in FIG. 4B is a differential addition signal when the negative multipliers N23 and N27 become coefficients other than 0 in addition to the 2-pixel interval.
  • coefficients other than 0 are set to the negative multipliers N22 and N28
  • the differential addition signals at intervals of 16 pixels are coefficients other than 0 for the negative multipliers N21 and N29. Is a differential addition signal when is set.
  • all differential addition signals of the present imaging apparatus output no video signal with improved modulation of low frequency (low frequency) because there is no high frequency component near fs / 2 including noise. It is something that can be done. Therefore, even when the input signal has a low degree of modulation, focusing at a telephoto end with a shallow depth of field can be facilitated.
  • FIG. 5 A contour correction signal in the present imaging device and a signal example after contour correction will be described with reference to FIG.
  • FIG. 5 is a schematic explanatory view showing a contour correction signal of the present imaging device and a signal example after contour correction.
  • FIG. 5 (a) shows a signal before correction
  • FIG. 5 (b) shows an edge correction signal based on a difference addition signal of 17H component / 17 pixel components (eight pixel intervals)
  • FIG. 5C shows 9H component / 9 pixel components
  • 4 (D) is a contour correction signal based on a 7H component / 7 pixel component (3 pixel interval) differential addition signal
  • (e) is a 5H component / 5 pixel component.
  • a contour correction signal based on a differential addition signal of (two pixel intervals) is a contour correction signal based on a differential addition signal of 3H component / 3 pixel components (one pixel interval), and (g) is 17H9H5H component / 17 (H) is a contour correction signal of 9H5H component / 9 pixels 5 pixel components (4 pixels 2 pixels interval) after contour correction with contour correction signal of 9 pixels 5 pixels 5 pixels component (8 pixels 4 pixels 2 pixels interval) Shows the signal after contour correction by.
  • (d) and (f) are signals that are not generated by the present imaging device, but are shown for reference.
  • the signal of (g) is based on the sum of the differential addition signal of 8-pixel intervals of (b), the differential addition signal of 4-pixel intervals of (c), and the differential addition signal of 2-pixel intervals of (e). This is a signal obtained by adding the generated contour correction signal and the pre-correction signal of (a).
  • the signal after contour correction shown in (g) is, for example, a 17H15H13H11H9H7H5H3H contour correction signal (a contour correction signal based on a difference addition signal of 17H15H13H11H9H9H7H5H3H component / 17 pixels 15 pixels 13 pixels 11 pixels 9 pixels 5 pixels 3 pixels component)
  • a contour correction signal based on a difference addition signal of 17H15H13H11H9H9H7H5H3H component / 17 pixels 15 pixels 13 pixels 11 pixels 9 pixels 5 pixels 3 pixels component
  • the signal of (h) is a contour correction signal generated based on the sum of the differential addition signal of 4-pixel intervals of (c) and the differential addition signal of 2-pixel intervals of (e), (a) It is a signal obtained by adding the pre-correction signal of The signal after contour correction in (h) is, for example, a high frequency component as compared with the case where it is corrected with a 9H7H5H3H contour correction signal (a contour correction signal based on a differential addition signal of 9H7H5H3H component / 9 pixels 7 pixels 5 pixels 3 pixel components) Although it is not possible to reproduce fine outlines of the image, the outline correction signal can be enlarged because the high frequency noise is small, and the outlines can be made clear.
  • the contour correction unit 11 in the image pickup apparatus using the CMOS image pickup element having a pixel interval of 5 wavelengths or less, the contour correction unit 11 generates an image signal of a pixel to be corrected.
  • the difference between the correction target pixel and the video signal of a plurality of pixels having a pixel interval (2, 4, 8, 18, 32, etc.) of powers of 2 is calculated, and the difference is added based on the difference.
  • the contour correction signal is generated, and the correction signal addition unit adds the contour correction signal to the video signal of the pixel to be corrected, so that a contour correction signal that does not include high frequency components near fs / 2 can be generated.
  • the low-range contour correction signal can be reinforced to improve the MTF in the low range, and focusing can be facilitated even at the telephoto end of a telephoto lens with a shallow depth of field.
  • the sum of the difference between the pixel to be compensated and the pixel having an interval of 2, 4, 8, 16, 32 pixels is calculated, but more line memories such as 64 pixels, 128 pixels, etc. It is also possible to use a configuration provided with a section or pixel delay section, a multiplier, and an adder, and the effect of contour correction increases as the number increases, so it is desirable to increase if the circuit scale is acceptable.
  • the video level discriminator output signal controls the contour correction signal level output from the small signal large amplitude compression limiter
  • the contour correction signal is controlled by controlling the video level discriminator output signal level according to the lens aperture value. It also becomes easy to control the level.
  • the monitoring 1 / 3-type HD2K imaging device, the reporting 2 / 3-type 4K imaging device, and the relay 4 / 3-type 8K imaging device have the same pixel interval of 2.5 ⁇ m, and are super telephoto.
  • the aberration is large, the diaphragm is dark, and the MTF is low.
  • these characteristics can be allowed to improve the MTF at low frequency, and the price of the imaging device can be reduced. There is an effect that can be realized. That is, the present apparatus has an effect of enabling outline emphasis at low cost by performing electronic correction without using an expensive large-sized low-pass MTF high UHDTV lens.
  • the present invention is suitable for an imaging apparatus capable of outputting a video signal with an improved degree of modulation at low frequencies by performing contour correction without high frequency components.

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Abstract

An imaging device which uses a surface radiation-type CMOS imaging element having a pixel pitch of less than or equal to 5 wavelengths is provided which improves MTF at low frequencies and which facilitates focusing even at the telephoto end. This imaging device, which uses a CMOS imaging element in which the pixel pitch is less than or equal to 5 times the center wavelength of imaging light, is provided with a color separation unit 2 which decomposes the incident light by color and outputs a video signal, and a contour correction unit 11, which, for the video signal from the color separation unit, calculates the difference between the video signal of pixels to be corrected by applying contour correction, and the video signal of multiple pixels which are separated by pixel intervals that are powers-of-two pixels long from said pixel to be corrected, generates a contour correction signal on the basis of a difference summation signal obtained by adding the differences, and performs contour correction by adding the contour correction signal to the video signal of the pixels to be corrected, wherein an contour correction signal is generated which does not include a high frequency component near fs/2.

Description

撮像装置Imaging device
　本発明は、撮像装置に係り、特に高周波数成分を含まない輪郭補正を行うことにより、低周波数における変調度を改善した映像信号を出力できる撮像装置に関する。 The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus capable of outputting a video signal with an improved degree of modulation at low frequencies by performing contour correction that does not include high frequency components.
［先行技術の説明］
　ＣＣＤ（Charge Coupled Device）撮像素子から出力された信号から雑音を除去するＣＤＳ（Correlated Double Sampling）と、暗電流補正と、利得可変増幅回路（Automatic Gain Control、以下ＡＧＣ）と、表示装置に出力するためデジタル映像信号Ｖｉに変換するＡＤＣ（Analog Digital Converter）とを内蔵したＡＦＥ（Analog Front End）が普及し、従来１０ビットだったＡＦＥのＡＤＣ階調は、１２ビットや１４ビットが一般的となった。
　また、駆動回路や読み出し回路を統合し高速読み出しを可能にしたＣＭＯＳ（Compleme
ntary Metal Oxide Semiconductor）撮像素子の改良も進んできた。 [Description of Prior Art]
Outputs to the display device CDS (Correlated Double Sampling) that removes noise from the signal output from the CCD (Charge Coupled Device) imaging device, dark current correction, variable gain amplifier circuit (Automatic Gain Control, hereinafter AGC), and a display device Therefore, AFE (Analog Front End) incorporating ADC (Analog Digital Converter) to convert to digital video signal Vi has become widespread, and ADC gradation of AFE, which was 10 bits in the past, is generally 12 bits or 14 bits. The
In addition, CMOS (Compleme) that integrates driving circuits and readout circuits to enable high-speed readout
Improvements in ntary metal oxide semiconductor) imaging devices have also progressed.
　更に、デジタル信号処理回路の集積化が進み、映像専用のメモリ集積ＤＳＰだけでなく、安価な汎用のＦＰＧＡ(Field Programmable Gate Array)でも、複数ラインの出力信号を記憶し算術処理することが容易に実現できるようになった。 Furthermore, with the progress of integration of digital signal processing circuits, it is easy to store and arithmetic process output signals of a plurality of lines not only for video memory-integrated DSPs but also for inexpensive general-purpose FPGAs (Field Programmable Gate Arrays). It came to be realized.
　それにより、画素数が百万以上のメガピクセルカメラ、ＨＤＴＶ（High Definition Te
leVision；高精細テレビ）カメラ、高速撮像ＨＤＴＶカメラ、記録部付ＨＤＴＶカメラ、Internet Protocol（以下ＩＰ）伝送部付ＨＤＴＶ（１０８０×１９２０）カメラ、より高精細の４Ｋ（２１６０×３８４０）カメラ、８Ｋ（４３２０×７６８０）カメラ等が製品化され、ＨＤＤ（Hard Disk Drive）を用いた非圧縮の記録装置も製品化されている。 As a result, megapixel cameras with one million pixels or more, HDTV (High Definition Te
leVision: high-definition television) camera, high-speed imaging HDTV camera, HDTV camera with recording unit, HDTV (1080 × 1920) camera with Internet Protocol (hereinafter IP) transmission unit, higher-definition 4K (2160 × 3840) camera, 8K (high-definition television) 4320 × 7680) Cameras and the like have been commercialized, and non-compression recording apparatuses using HDDs (Hard Disk Drives) have also been commercialized.
［撮像素子の構成：図６］
　ここで、撮像素子の構成について図６用いて説明する。図６は、撮像素子の構成を示す断面説明図であり、（ａ）はＣＣＤセンサー（撮像素子）、（ｂ）は従来型ＣＭＯＳセンサー（表面照射型ＣＭＯＳ撮像素子）、（ｃ）はＢＳＩ（Back Side Illumination）型ＣＭＯＳセンサー（裏面照射型ＣＭＯＳ撮像素子）を示している。
　図６（ａ）に示すように、ＣＣＤセンサーは、マイクロレンズ９１と、カラーフィルタ９２と、フォトダイオード９３とが積層され、フォトダイオード９３とカラーフィルタ９２との間にメタル配線層９４が形成されている。 [Configuration of imaging device: FIG. 6]
Here, the configuration of the imaging device will be described with reference to FIG. FIG. 6 is a cross-sectional explanatory view showing the configuration of the imaging device, where (a) is a CCD sensor (imaging device), (b) is a conventional CMOS sensor (surface-illuminated CMOS imaging device), (c) is BSI ( The back side illumination) type CMOS sensor (back side illumination type CMOS image sensor) is shown.
As shown in FIG. 6A, in the CCD sensor, a microlens 91, a color filter 92, and a photodiode 93 are stacked, and a metal wiring layer 94 is formed between the photodiode 93 and the color filter 92. ing.
　マイクロレンズ９１によって集光された入射光は、カラーフィルタ９２を通過して、Ｒ（赤），Ｇ（緑），Ｂ（青）の成分に分解され、フォトダイオード９３に入射されて電荷が発生し、垂直方向及び水平方向に転送されて画素毎の電圧に変換される。
　ＣＣＤセンサーは、感度は高いものの、消費電力が大きく、ＣＭＯＳ撮像素子に比べて周辺回路の集積が困難である。 Incident light collected by the micro lens 91 passes through the color filter 92, is separated into R (red), G (green) and B (blue) components, and is incident on the photodiode 93 to generate charge. Are transferred in the vertical direction and the horizontal direction to be converted into a voltage for each pixel.
Although the CCD sensor has high sensitivity, it consumes a large amount of power and is difficult to integrate peripheral circuits as compared to a CMOS image sensor.
　図６（ｂ）に示す表面照射型ＣＭＯＳ撮像素子は、画素毎にトランジスタ等が設けられた構成であり、低消費電力、集積化が容易であるものの、感度は低い。
　図６（ｃ）に示す裏面照射型ＣＭＯＳ撮像素子は、メタル配線層９３がフォトダイオード９３の裏面側に設けられており、高感度で、低消費電力、集積化が容易である。 The surface-illuminated CMOS imaging device shown in FIG. 6B has a configuration in which a transistor or the like is provided for each pixel, and although low power consumption and easy integration are possible, sensitivity is low.
In the backside illuminated CMOS imaging device shown in FIG. 6C, the metal wiring layer 93 is provided on the backside of the photodiode 93, so that it is highly sensitive, low power consumption, and easy to integrate.
　特に、一般的な低価格の表面照射型ＣＭＯＳ撮像素子（８Ｋで１．２５型を含め４／３型以下、４Ｋで２／３型以下）は、５波長以下の画素間隔で、フォトダイオード９３とマイクロレンズ（オンチップレンズ）９１との間にメタル配線層９４が積層されているため、低域の変調度が低い。
　また、対域外の高域成分の折り返しの偽信号のモアレを抑圧するために光学低域通過フィルタ（Ｏ－ＬＰＦ；Optical Low Pass Filter）を挿入すると、更に変調度が低くなる。 In particular, a general-purpose low-cost surface-illuminated CMOS imaging device (4/3 or less including 8K, 1.25 type, 2/3 or less at 4K) has photodiode 93 with pixel spacing of 5 wavelengths or less. Since the metal wiring layer 94 is stacked between the first and second microlenses (on-chip lenses) 91, the degree of modulation in the low region is low.
In addition, if an optical low pass filter (O-LPF; Optical Low Pass Filter) is inserted to suppress moire of aliasing of high frequency components outside the range, the degree of modulation further decreases.
　更に、２／３型４Ｋと１．２５型８Ｋにおいては、撮像素子の画素ピッチが約２．５μｍと緑波長０．５５μｍの約４．５倍となり、高倍率ズームレンズの収差を光学的に補正しきれず、低域での変調度（変調伝達関数特性：ＭＴＦ；Modulation Transfer Function
）が低下する。 Furthermore, in 2/3 type 4K and 1.25 type 8K, the pixel pitch of the image pickup element is about 2.5 μm and about 4.5 times the green wavelength 0.55 μm, and the aberration of the high magnification zoom lens is optically It can not be corrected, and the degree of modulation at low frequencies (Modulation transfer function characteristics: MTF; Modulation Transfer Function
) Decreases.
　図７は、絞り値と変調度の関係を示す説明図である。
　収差のない理想レンズでも、画素ピッチの波長数以上に絞ると、緑の中心波長０．５５μｍの光学回折により変調度が低下することが知られている。
　例えば、１／３型ＨＤＴＶ（１０８０×１９２０）カメラでは、画素ピッチが４．９波長に対し、約Ｆ５で４００ＴＶ本でも変調度５０％以下のぼけた画像となり、２／３型４Ｋ（２１６０×３８４０）カメラでは、画素ピッチが４．５波長に対し、約Ｆ４．８で８００ＴＶ本でも変調度５０％以下のぼけた画像となる。 FIG. 7 is an explanatory view showing the relationship between the aperture value and the modulation degree.
It is known that, even with an ideal lens having no aberration, the degree of modulation decreases due to optical diffraction at a green central wavelength of 0.55 μm when the number of wavelengths of the pixel pitch is reduced to a number equal to or greater than the wavelength.
For example, with a 1/3 type HDTV (1080 × 1920) camera, a blurred image with a pixel pitch of approximately F5 and a 400 TV line with a modulation degree of 50% or less with an F5 pixel wavelength of 4.9 wavelengths is 2/3 × 4K (2160 × With the camera, with the camera, for a pixel pitch of 4.5 wavelengths, an blurred image with a modulation degree of 50% or less is obtained even at 800 TV with about F4.8.
　実際のレンズでは、一般的に、ＨＤＴＶ（１０８０×１９２０）カメラ用でＦ４付近、４Ｋ（２１６０×３８４０）カメラ用でＦ２．８付近、８Ｋ（４３２０×７６８０）カメラ用でＦ２付近において変調度が最も高く、絞り開放付近では収差のため変調度が低下し、絞り切り付近では光学回折のため変調度が低下する。 In an actual lens, in general, the modulation degree is around F4 for HDTV (1080 × 1920) cameras, around F2.8 for 4K (2160 × 3840) cameras, and around F2 for 8K (4320 × 7680) cameras. At the highest, the degree of modulation decreases in the vicinity of the aperture opening due to aberration, and the degree of modulation decreases in the vicinity of the stop due to optical diffraction.
　一方、望遠ズームレンズは、望遠端の絞り値が３．７から５．３と５．６に近く、エクステンダと称する焦点距離を２倍にする補助レンズを挿入すると絞り値が倍になり、望遠端の絞り値が７．４から１０．６と５．６よりはるかに大きくなる。
　更に、望遠端では収差のため変調度が低下する。そのため、望遠端ではｆｓ／２付近の信号成分はほとんどなく、雑音が主成分となる。 On the other hand, in the telephoto zoom lens, when the stop value at the telephoto end is close to 3.7 to 5.3 and 5.6, inserting an auxiliary lens called an extender that doubles the focal length doubles the stop value, The aperture values at the ends become much larger than 7.4 to 10.6 and 5.6.
Furthermore, at the telephoto end, the degree of modulation is reduced due to the aberration. Therefore, at the telephoto end, there are almost no signal components near fs / 2, and noise is the main component.
［関連技術］
　尚、撮像装置に関する従来技術としては、特開２００７－４９２１６号公報「輪郭強調処理装置及び輪郭強調処理方法」（特許文献１）、特開平７－２６４４４２号公報「固体撮像装置」（特許文献２）、特開２００３－３３３３６９号公報「画像処理装置および方法、記録媒体、並びにプログラム」（特許文献３）、特開２００９－３０３２０６号公報「個体撮像装置及び監視システム」（特許文献４）がある。 [Related Art]
In addition, as a prior art regarding an imaging device, Unexamined-Japanese-Patent No. 2007-49216 "outline emphasis processing apparatus and outline emphasis processing method" (patent document 1), Unexamined-Japanese-Patent No. 7-264442 "solid-state imaging apparatus" (patent document 2) Japanese Patent Application Laid-Open No. 2003-333369 "Image processing apparatus and method, recording medium, and program" (patent document 3) Japanese Patent Application Laid-Open No. 2009-303206 "Individual image pickup apparatus and monitoring system" (patent document 4) .
　特許文献１には、サンプリング周波数ｆｓの半分付近の信号成分と雑音成分を減衰させるため、輪郭補正信号を、低域通過フィルタ（ＬＰＦ；Low Pass Filter）を通過させる輪郭強調処理装置が記載されている。
　特許文献２には、望遠で変調度が低下する場合に、輪郭補正周波数を低下させる撮像装置が記載されている。 Patent Document 1 describes an edge enhancement processing apparatus for passing an edge correction signal through a low pass filter (LPF; Low Pass Filter) in order to attenuate signal components and noise components around half the sampling frequency fs. There is.
Patent Document 2 describes an imaging device that reduces the contour correction frequency when the degree of modulation decreases at telephoto.
　また、特許文献３には、基本処理レートの２の累乗数に対応した遅延から輪郭強調（２又は４の単位の画素間隔の差分の輪郭補正）を行うことが記載されている。
　特許文献４には、絞り値が大きく、光学回折で変調度が低下すると、輪郭補正の中心周波数を低下させる撮像装置が記載されている。 Further, Patent Document 3 describes that edge enhancement (edge correction of a difference between pixel intervals in units of 2 or 4) is performed from a delay corresponding to a power of 2 of the basic processing rate.
Patent Document 4 describes an imaging device that reduces the center frequency of contour correction when the aperture value is large and the degree of modulation is reduced by optical diffraction.
特開２００７－４９２１６号公報Japanese Patent Application Publication No. 2007-49216 特開平７－２６４４４２号公報Unexamined-Japanese-Patent No. 7-264442 gazette 特開２００３－３３３３６９号公報JP 2003-333369 特開２００９－３０３２０６号公報JP, 2009-303206, A
　上述したように、従来の撮像装置では、表面照射型ＣＭＯＳ撮像素子を用いたＵＨＤＴＶ（Ultra High Definition TeleVision:超高精細テレビ）カメラにおいては、画素ピッチが撮像光の中心波長の５波長以下になると、低周波数におけるＭＴＦが低下するという問題点があった。
　また、望遠ズームレンズの望遠端では、特にレンズ収差と回折からＭＴＦが低下し、焦点合わせが困難であるという問題点があった。 As described above, in a conventional imaging device, in a UHDTV (Ultra High Definition TeleVision: ultra high definition television) camera using a surface-illuminated CMOS imaging device, if the pixel pitch is equal to or less than five wavelengths of the central wavelength of imaging light There is a problem that MTF at low frequencies is lowered.
In addition, at the telephoto end of the telephoto zoom lens, the MTF particularly decreases due to lens aberration and diffraction, which causes a problem that focusing is difficult.
　本発明は上記実状に鑑みて為されたもので、画素ピッチが５波長以下の表面照射型ＣＭＯＳ撮像素子を用いた撮像装置において、低周波数におけるＭＴＦを改善し、望遠端でも焦点合わせを容易にすることができる撮像装置を提供することを目的とする。 The present invention has been made in view of the above circumstances, and in an imaging apparatus using a surface-illuminated CMOS imaging device having a pixel pitch of 5 wavelengths or less, the MTF at low frequencies is improved and focusing is easy even at the telephoto end. It is an object of the present invention to provide an imaging device that can
　上記従来例の問題点を解決するための本発明は、画素ピッチが撮像光の中心波長の５倍以下であるＣＭＯＳ撮像素子を用いた撮像装置であって、撮像素子を備え、入力光を色毎に分解して映像信号を出力する色分解部と、色分解部からの映像信号について、輪郭補正を施す補正対象の画素の映像信号と、当該補正対象の画素から２の累乗の画素間隔となる複数の画素の映像信号との差分を算出し、当該複数の差分を加算した差分加算信号に基づいて輪郭補正信号を生成し、補正対象画素の映像信号に輪郭補正信号を加算して輪郭補正を行う輪郭補正部とを備えたことを特徴としている。 The present invention for solving the problems of the above-described conventional example is an imaging apparatus using a CMOS imaging device whose pixel pitch is five times or less of the central wavelength of imaging light, and comprises an imaging device and color input light A color separation unit that separates each time and outputs a video signal, and a video signal of a correction target pixel to which contour correction is applied to the video signal from the color separation unit, and a pixel interval of a power of 2 from the correction target pixel The difference with the video signal of the plurality of pixels is calculated, the contour correction signal is generated based on the difference addition signal obtained by adding the plurality of differences, the contour correction signal is added to the video signal of the correction target pixel, and the contour correction is performed. And a contour correction unit for performing the processing.
　また、本発明は、上記撮像装置において、輪郭補正部が、補正対象の画素の映像信号と、補正対象の画素から２の累乗の画素間隔となる複数の画素の映像信号との差分を算出し、当該複数の差分を加算して差分加算信号を生成する差分加算部と、差分加算信号を、補正対象の画素の映像信号レベルに基づいて調整して補正対象の画素に対応する輪郭補正信号を生成する輪郭補正信号生成部と、補正対象の画素の映像信号に輪郭補正信号を加算する輪郭補正信号加算部とを備えたことを特徴としている。 Further, according to the present invention, in the imaging device, the outline correction unit calculates a difference between the video signal of the pixel to be corrected and the video signal of a plurality of pixels having a pixel interval of a power of 2 from the pixel to be corrected. A difference addition unit that adds the plurality of differences to generate a difference addition signal; and adjusting the difference addition signal based on the video signal level of the pixel to be corrected; and an edge correction signal corresponding to the pixel to be corrected It is characterized in that it comprises: a contour correction signal generation unit to be generated; and a contour correction signal addition unit to add a contour correction signal to a video signal of a pixel to be corrected.
　また、本発明は、上記撮像装置において、２の累乗の画素間隔を、２画素間隔から３２画素間隔までとすることを特徴としている。 Furthermore, the present invention is characterized in that, in the above-mentioned imaging device, the pixel interval of the power of 2 is from 2 pixel interval to 32 pixel interval.
　また、本発明は、上記撮像装置において、撮像素子を表面照射型のＣＭＯＳ撮像素子としたことを特徴としている。 Furthermore, the present invention is characterized in that, in the above-described imaging device, the imaging device is a surface-illuminated CMOS imaging device.
　また、本発明は、上記撮像装置において、望遠端の開放絞り値が、撮像素子の画素ピッチ／中心波長より大きいレンズ、又は収差の大きいレンズから入力される映像信号について、輪郭補正を行うことを特徴としている。 Further, according to the present invention, in the imaging device described above, contour correction is performed on a video signal input from a lens whose open aperture value at the telephoto end is larger than the pixel pitch of the imaging device / center wavelength or a lens with large aberration. It is characterized.
　本発明によれば、画素ピッチが撮像光の中心波長の５倍以下であるＣＭＯＳ撮像素子を用いた撮像装置であって、撮像素子を備え、入力光を色毎に分解して映像信号を出力する色分解部と、色分解部からの映像信号について、輪郭補正を施す補正対象の画素の映像信号と、当該補正対象の画素から２の累乗の画素間隔となる複数の画素の映像信号との差分を算出し、当該複数の差分を加算した差分加算信号に基づいて輪郭補正信号を生成し、補正対象画素の映像信号に輪郭補正信号を加算して輪郭補正を行う輪郭補正部とを備えた撮像装置としているので、高周波成分を含まない輪郭補正信号を生成して、低域の輪郭補正信号を強調し、低域における変調度を改善し、被写界深度の浅い望遠端における焦点合わせを容易にすることができる効果がある。 According to the present invention, an imaging device using a CMOS imaging device having a pixel pitch equal to or less than five times the central wavelength of imaging light, comprising an imaging device, separating input light for each color and outputting a video signal A color separation unit, a video signal of a correction target pixel to which contour correction is applied to a video signal from the color separation unit, and a video signal of a plurality of pixels having a pixel interval of a power of 2 from the correction target pixel A contour correction unit that calculates a difference, generates an edge correction signal based on a difference addition signal obtained by adding the plurality of differences, and adds an edge correction signal to a video signal of a correction target pixel to perform edge correction Since the imaging apparatus is used, a contour correction signal containing no high frequency component is generated to emphasize the low band contour correction signal, improve the modulation degree in the low band, and focus at the telephoto end with a shallow depth of field. Can be facilitated There is a result.
　また、本発明によれば、輪郭補正部が、補正対象の画素の映像信号と、補正対象の画素から２の累乗の画素間隔となる複数の画素の映像信号との差分を算出し、当該複数の差分を加算して差分加算信号を生成する差分加算部と、差分加算信号を、補正対象の画素の映像信号レベルに基づいて調整して補正対象の画素に対応する輪郭補正信号を生成する輪郭補正信号生成部と、補正対象の画素の映像信号に輪郭補正信号を加算する輪郭補正信号加算部とを備えた上記撮像装置としているので、差分加算信号を適切に調整して輪郭補正信号を生成することができ、低域における変調度を改善することができる効果がある。 Further, according to the present invention, the contour correction unit calculates the difference between the video signal of the pixel to be corrected and the video signal of a plurality of pixels having a pixel interval of a power of 2 from the pixel to be corrected A difference addition unit that generates a difference addition signal by adding the differences of the above, and an outline that adjusts the difference addition signal based on the video signal level of the pixel to be corrected to generate an edge correction signal corresponding to the pixel to be corrected Since the imaging apparatus includes the correction signal generation unit and the contour correction signal addition unit that adds the contour correction signal to the video signal of the pixel to be corrected, the difference addition signal is appropriately adjusted to generate the contour correction signal. There is an effect that the degree of modulation in the low band can be improved.
　また、本発明によれば、２の累乗の画素間隔を、２画素間隔から３２画素間隔までとする上記撮像装置としているので、２Ｋの飛越操作のＨＤＴＶの１．０５ＭＨｚの変調度を改善すると共に、１ＭＨｚ基準の２７．５ＭＨｚの変調度を相対的に低下させることができ、回路規模をあまり大きくすることなく、低域における変調度を十分改善することができる効果がある。 Further, according to the present invention, since the image pickup apparatus has the pixel interval of power of 2 from 2 pixel interval to 32 pixel interval, the modulation degree of 1.05 MHz of HDTV of 2K jump operation is improved. The degree of modulation at 27.5 MHz, which is based on 1 MHz, can be relatively lowered, and the degree of modulation in the low band can be sufficiently improved without increasing the circuit scale too much.
　また、本発明によれば、撮像素子を表面照射型のＣＭＯＳ撮像素子とした上記撮像装置としているので、低コストで低域の変調度を改善した撮像素子を実現することができる効果がある。 Further, according to the present invention, since the imaging device is configured as the surface-illuminated CMOS imaging device according to the present invention, there is an effect that it is possible to realize an imaging device with improved low-frequency modulation at low cost.
　また、本発明によれば、望遠端の開放絞り値が、撮像素子の画素ピッチ／中心波長より大きいレンズ、又は収差の大きいレンズから入力される映像信号について、輪郭補正を行う上記撮像装置としているので、高価で大型のＵＨＤＴＶ専用レンズを使用することなく、低コストで低域における変調度を改善して、望遠端での焦点合わせを容易にすることができる効果がある。 Further, according to the present invention, the image pickup apparatus performs the contour correction on a video signal input from a lens whose open aperture value at the telephoto end is larger than the pixel pitch of the image pickup element / center wavelength or a lens having large aberration. Therefore, it is possible to improve the degree of modulation at low cost and to facilitate focusing at the telephoto end without using an expensive and large UHDTV lens.
本撮像装置の概略構成を示す構成ブロック図である。It is a structure block diagram showing a schematic structure of this imaging device. 本撮像装置の垂直輪郭補正部の構成図である。It is a block diagram of the vertical contour correction part of this imaging device. 本撮像装置の水平輪郭補正部の構成図である。It is a block diagram of the horizontal outline correction part of this imaging device. ２，４，８，１６画素間隔の差分加算信号の周波数軸表示である。It is a frequency-axis display of the difference addition signal of a 2, 4, 8, 16 pixel space | interval. 本撮像装置の輪郭補正信号及び輪郭補正後の信号例を示す模式説明図である。It is model explanatory drawing which shows the signal example of an outline correction signal of this imaging device, and an outline correction. 撮像素子の構成を示す断面説明図である。It is a section explanatory view showing the composition of an image sensor. 絞り値と変調度の関係を示す説明図である。It is explanatory drawing which shows the relationship between aperture value and modulation degree.
　本発明の実施の形態について図面を参照しながら説明する。
［実施の形態の概要］
　本発明の実施の形態に係る撮像装置は、画素ピッチが撮像光の中心波長の５波長以下のＣＭＯＳ撮像素子を用いた撮像装置において、輪郭補正を施す補正対象の画素の映像信号と、当該補正対象の画素から２の累乗の画素間隔となる複数の画素の映像信号との差分を算出し、当該複数の差分を加算した差分加算信号に基づいて輪郭補正信号を生成し、補正対象画素の映像信号に輪郭補正信号を加算するようにしているので、ｆｓ／２付近の高周波成分を含まない輪郭補正信号とすることができ、低域の輪郭補正信号を補強して、低域におけるＭＴＦを改善し、望遠レンズの望遠端においても焦点合わせを容易にすることができるものである。 Embodiments of the present invention will be described with reference to the drawings.
[Overview of the embodiment]
An image pickup apparatus according to an embodiment of the present invention is an image pickup apparatus using a CMOS image pickup element having a pixel pitch of 5 wavelengths or less of a central wavelength of image pickup light. The difference between the target pixel and the video signal of the plurality of pixels which is the pixel interval of the power of 2 is calculated, and the contour correction signal is generated based on the difference addition signal obtained by adding the plurality of differences. Since the contour correction signal is added to the signal, the contour correction signal without high frequency components near fs / 2 can be obtained, and the low frequency contour correction signal is reinforced to improve the MTF in the low frequency region. Also, focusing can be facilitated at the telephoto end of the telephoto lens.
［実施の形態に係る撮像装置の概略構成：図１］
　本発明の実施の形態に係る撮像装置（本撮像装置）の概略構成について図１を用いて説明する。図１は、本撮像装置の概略構成を示す構成ブロック図である。
　図１に示すように、本撮像装置１は、色分解光学系２と、撮像素子３（３Ｒ，３Ｇ，３Ｂ）と、映像信号処理部４と、パラレル／シリアル（Ｐ／Ｓ）変換部５と、ＣＰＵ（Cent
ral Processing Unit）６とを備えており、レンズ７及びビューファインダー（映像表示装置）８に接続されている。 [Schematic Configuration of Imaging Device According to Embodiment: FIG. 1]
A schematic configuration of an imaging apparatus (main imaging apparatus) according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a configuration block diagram showing a schematic configuration of the present imaging device.
As shown in FIG. 1, the imaging device 1 includes a color separation optical system 2, an imaging device 3 (3 R, 3 G, 3 B), a video signal processing unit 4, and a parallel / serial (P / S) conversion unit 5. And the CPU (Cent
ral Processing Unit) 6 and is connected to the lens 7 and the view finder (image display device) 8.
　本撮像装置１の各部について説明する。
　色分解光学系２は、レンズ７から入射された入射光を赤色（Ｒ）と、緑色（Ｇ）と、青色（Ｂ）に色分解する。
　撮像素子３は、ＣＭＯＳ撮像素子であり、撮像素子３Ｒは赤色光を光電変換し、撮像素子３Ｇは緑色光を光電変換し、撮像素子３Ｂは青色光を光電変換して、各色の光の強弱に応じた電荷を発生する。
　ここで、撮像素子３は、緑色光の波長（０．５５μｍ）を基準として５波長以下の画素ピッチで画素が配列されている。
　色分解光学系２及び撮像素子３は、請求項に記載した色分解部に相当している。 Each part of the imaging device 1 will be described.
The color separation optical system 2 separates the incident light from the lens 7 into red (R), green (G) and blue (B).
The image pickup device 3 is a CMOS image pickup device, the image pickup device 3R photoelectrically converts red light, the image pickup device 3G photoelectrically converts green light, and the image pickup device 3B photoelectrically converts blue light. Generates a charge according to the
Here, the pixels of the imaging device 3 are arranged at a pixel pitch of 5 wavelengths or less based on the wavelength (0.55 μm) of green light.
The color separation optical system 2 and the imaging device 3 correspond to a color separation unit described in the claims.
　映像信号処理部４は、輪郭補正部１１と、ガンマ色補正部１２と、マトリクス部１３とを備え、大容量メモリ内蔵ＦＰＧＡや、ＤＤＲ（Double-Data-Rate）メモリ外付けＦＰＧＡ等で構成される。 The video signal processing unit 4 includes a contour correction unit 11, a gamma color correction unit 12, and a matrix unit 13, and is configured by an FPGA with a large capacity memory, an external FPGA with DDR (Double-Data-Rate) memory, etc. Ru.
　輪郭補正部１１は、本撮像装置の特徴部分であり、赤、緑、青の各色成分毎に、映像の輪郭を補正する輪郭補正処理を行う。
　輪郭補正部１１は、垂直輪郭補正処理を行う直輪郭補正部と、水平輪郭補正処理を行う水平輪郭補正処理部とを備えている。 The contour correction unit 11 is a characteristic portion of the present imaging device, and performs contour correction processing for correcting the contour of the image for each of the red, green, and blue color components.
The contour correction unit 11 includes a direct contour correction unit that performs vertical contour correction processing, and a horizontal contour correction processing unit that performs horizontal contour correction processing.
　そして、本撮像装置の特徴として、輪郭補正部１１は、補正対象の画素の映像信号と、２の累乗の画素間隔（例えば、２，４，８，１６，３２画素間隔）となる画素の映像信号との差分の合計に基づいて、輪郭補正信号を生成する。輪郭補正部１１の構成及び動作については後述する。 Then, as a feature of the present imaging device, the contour correction unit 11 generates an image of a pixel to be corrected and an image of a pixel having a pixel interval of a power of 2 (for example, an interval of 2, 4, 8, 16, 32 pixels) A contour correction signal is generated based on the sum of the difference with the signal. The configuration and operation of the contour correction unit 11 will be described later.
　ガンマ色補正部１２は、画像の階調を補正（ガンマ色補正）する処理を行う。
　マトリクス部１３は、映像の輝度や色を調整する処理を行う。
　パラレル／シリアル変換部５は、パラレルデータをシリアルデータに変換して、外部に出力する。
　ＣＰＵ６は、撮像装置全体の制御を行うものであり、特に、輪郭補正部１１の制御を行って適切な輪郭補正を実現する。
　また、ＣＰＵ６は、レンズ絞り値に応じて輪郭補正信号のレベルを制御する。 The gamma color correction unit 12 performs processing of correcting the gradation of the image (gamma color correction).
The matrix unit 13 performs processing to adjust the luminance and color of the video.
The parallel / serial converter 5 converts parallel data into serial data and outputs the serial data to the outside.
The CPU 6 controls the entire image pickup apparatus, and in particular, controls the contour correction unit 11 to realize appropriate contour correction.
Further, the CPU 6 controls the level of the contour correction signal in accordance with the lens aperture value.
　本撮像装置の動作について簡単に説明する。
　レンズ７から入力された光は、色分解光学系２において赤、緑、青の成分に分離され、それぞれ、撮像素子３Ｒ，３Ｇ，３Ｂで光電変換されて電気信号となる。
　そして、各色の信号は、輪郭補正部１１において、それぞれ垂直輪郭補正及び水平輪郭補正処理を施され、ガンマ色補正部１２でガンマ色補正が為され、マトリクス部１３で色調整を施され、パラレル／シリアル変換部５でシリアルデータに変換されて、映像信号として外部に出力される。 The operation of the present imaging device will be briefly described.
The light input from the lens 7 is separated into red, green, and blue components in the color separation optical system 2, and is photoelectrically converted by the imaging elements 3R, 3G, and 3B, respectively, to form an electric signal.
The signal of each color is subjected to vertical contour correction and horizontal contour correction processing in the contour correction unit 11, gamma color correction is performed in the gamma color correction unit 12, color adjustment is performed in the matrix unit 13, and the parallel correction is performed. The serial data is converted into serial data by the / serial converter 5 and output to the outside as a video signal.
［垂直輪郭補正部の構成：図２］
　次に、本撮像装置の特徴部分である、輪郭補正部１１の垂直輪郭補正部の構成について図２を用いて説明する。図２は、本撮像装置の垂直輪郭補正部の構成図である。
　垂直輪郭補正部１１は、垂直方向に配列された画素間の映像信号を比較して、垂直方向の輪郭を補正するものである。
　図２に示すように、垂直輪郭補正部は、複数のラインメモリ部Ｍ２０～Ｍ２９と、複数の負の乗算器Ｎ２０～Ｎ２４及びＮ２６～Ｎ３０と、正の乗算器Ｐ２５と、複数の加算器２０～２９と、映像レベル判定器２８と、乗算器２９，３２と、小振幅大振幅圧縮制限器３１と、補正信号加算部３３とを備えている。 [Configuration of vertical contour correction unit: FIG. 2]
Next, the configuration of the vertical contour correction unit of the contour correction unit 11, which is a characteristic part of the present imaging device, will be described using FIG. FIG. 2 is a block diagram of the vertical contour correction unit of the present imaging device.
The vertical contour correction unit 11 corrects the contour in the vertical direction by comparing video signals between pixels arranged in the vertical direction.
As shown in FIG. 2, the vertical contour correction unit includes a plurality of line memory units M20 to M29, a plurality of negative multipliers N20 to N24 and N26 to N30, a positive multiplier P25, and a plurality of adders 20. , A video level determination unit 28, multipliers 29 and 32, a small amplitude / large amplitude compression limiter 31, and a correction signal addition unit 33.
　ここで、ラインメモリ部Ｍ２０～Ｍ２９と、負の乗算器Ｎ２０～Ｎ２４及びＮ２６～Ｎ３０と、正の乗算器Ｐ２５と、複数の加算器２０～２９とが請求項に記載した差分加算部に相当し、映像レベル判定器２８と、乗算器２９，３２が輪郭補正信号生成部に相当している。 Here, the line memory units M20 to M29, the negative multipliers N20 to N24 and N26 to N30, the positive multiplier P25, and the plurality of adders 20 to 29 correspond to the difference addition unit described in the claims. The video level determination unit 28 and the multipliers 29 and 32 correspond to the contour correction signal generation unit.
　垂直輪郭補正部の各部について説明する。
　ラインメモリ部は、補正対象となるライン（３２Ｈとする）の映像信号と、本装置の特徴部分である補正対象ラインから垂直方向に２，４，８，１６，３２画素だけ離れたラインの映像信号との差分を求めるために、必要な映像信号を保持して出力するものである。 Each part of the vertical contour correction unit will be described.
The line memory unit includes an image signal of a line (referred to as 32H) to be corrected and an image of a line separated by 2, 4, 8, 16 and 32 pixels in the vertical direction from the line to be corrected which is a characteristic portion of the apparatus. A necessary video signal is held and output in order to obtain a difference from the signal.
　具体的には、ラインメモリ部Ｍ２０は１６ライン分の映像信号を蓄積し、ラインメモリ部Ｍ２１は８ライン分の映像信号を蓄積し、ラインメモリ部Ｍ２２は４ライン分の映像信号を蓄積し、ラインメモリ部Ｍ２３は２ライン分の映像信号を蓄積して、それぞれ１ラインずつ負の乗算器Ｎ２１～Ｎ２４に出力する。 Specifically, the line memory unit M20 stores video signals of 16 lines, the line memory unit M21 stores video signals of 8 lines, and the line memory unit M22 stores video signals of 4 lines, The line memory unit M23 accumulates video signals for two lines, and outputs one line each to negative multipliers N21 to N24.
　ラインメモリ部Ｍ２４は、補正対象ライン（３２Ｈ）とその次のライン（３１Ｈ）とを保持して、補正対象ラインを正の乗算器Ｐ２５、映像レベル判定器２８、及び輪郭補正信号加算部３３に出力する。 The line memory unit M24 holds the line to be corrected (32H) and the next line (31H), and sends the line to be corrected to the positive multiplier P25, the video level judgment unit 28, and the outline correction signal addition unit 33. Output.
　また、ラインメモリ部Ｍ２５及びＭ２６は、それぞれ２ライン分の映像信号を蓄積し、ラインメモリ部Ｍ２７は４ライン分の映像信号を蓄積し、ラインメモリ部Ｍ２８は８ライン分の映像信号を蓄積し、ラインメモリ部Ｍ２９は１６ライン分の映像信号を蓄積して、それぞれ１ラインずつ負の乗算器Ｎ２６～Ｎ３０に出力する。 Line memory units M25 and M26 store video signals for two lines, line memory unit M27 stores video signals for four lines, and line memory unit M28 stores video signals for eight lines. The line memory unit M29 accumulates video signals of 16 lines, and outputs the video signals to negative multipliers N26 to N30, respectively, one line at a time.
　負の乗算器Ｎ２１～Ｎ２４は、ラインメモリ部Ｍ２０～Ｍ２３から出力された映像信号に負の係数を乗算し、加算器２１～２４に出力する。
　負の乗算器Ｎ２６～Ｎ３０は、ラインメモリ部Ｍ２５～Ｍ２９から出力された映像信号に負の係数を乗算し、加算器２６～２９に出力する。
　負の乗算器Ｎ２０は、補正前の信号に負の係数を乗算し、加算器２０に出力する。
　正の乗算器Ｐ２５は、ラインメモリＭ２４から出力された補正対象ライン（３２Ｈ）の映像信号に、正の係数を乗算する。 The negative multipliers N21 to N24 multiply the video signals output from the line memory units M20 to M23 by negative coefficients, and output the result to the adders 21 to 24.
Negative multipliers N26 to N30 multiply the video signals output from the line memory units M25 to M29 by negative coefficients, and output the result to the adders 26 to 29.
The negative multiplier N20 multiplies the signal before correction by a negative coefficient, and outputs the result to the adder 20.
The positive multiplier P25 multiplies the video signal of the correction target line (32H) output from the line memory M24 by a positive coefficient.
　加算器２０～２９は、負の乗算器Ｎ２０～Ｎ２４、Ｎ２６～Ｎ３０と、正の乗算器Ｐ２５の出力を加算して、加算器２０から差分加算信号を出力する。加算器２０～２９は、請求項における差分加算部に相当している。
　ここで、加算器２０において、各負の乗算器からの出力と正の乗算器Ｐ２５からの出力との差分の合計が算出されるよう、正の乗算器Ｐ２５の係数又は／及び負の乗算器Ｎ２０～Ｎ２４、Ｎ２６～Ｎ３０の係数がＣＰＵ６からの指示により調整されている。 The adders 20 to 29 add the outputs of the negative multipliers N20 to N24 and N26 to N30 and the positive multiplier P25, and output a difference addition signal from the adder 20. The adders 20 to 29 correspond to the difference addition unit in the claims.
Here, the coefficient of positive multiplier P25 or / and the negative multiplier such that the sum of the difference between the output from each negative multiplier and the output from positive multiplier P25 is calculated in adder 20. The coefficients of N20 to N24 and N26 to N30 are adjusted in accordance with an instruction from the CPU 6.
　つまり、加算器２０から出力される差分加算信号は、補正対象ライン（３２Ｈ）の映像信号と、補正対象ラインから２の累乗数（ここでは、２，４，８，１６，３２）だけ離れたラインの映像信号との差分の合計となる。
　このように２の累乗数の間隔で差分信号を求め、加算して輪郭補正信号を生成することで、高周波数成分のない輪郭補正信号を生成できるものである。 That is, the difference addition signal output from the adder 20 is separated from the correction target line (32H) by the power of two (here, 2, 4, 8, 16, 32) from the correction target line. It is the sum of the difference with the video signal of the line.
As described above, by obtaining a difference signal at intervals of powers of 2 and adding them to generate a contour correction signal, it is possible to generate a contour correction signal without high frequency components.
　映像レベル判定器２８は、補正対象ラインの映像信号のレベルを判定して、しきい値判定により暗部を検出する。
　乗算器２９は、暗部の輪郭補正信号を減衰させるため、正負及び増幅度を可変調整する。
　映像レベル判定器２８及び乗算器２９により、映像レベルが低い領域では、輪郭補正信号付加によるノイズを低減するために、輪郭補正信号を小さくする制御を行い、任意の映像レベル以上の場合には、輪郭補正信号のレベルを一定とする制御を行う。 The video level determination unit 28 determines the level of the video signal of the correction target line, and detects a dark portion by threshold determination.
The multiplier 29 variably adjusts the positive / negative and amplification degree in order to attenuate the outline correction signal of the dark part.
In the region where the video level is low, the video level determination unit 28 and the multiplier 29 perform control to reduce the contour correction signal in order to reduce noise due to addition of the contour correction signal. Control is performed to keep the level of the contour correction signal constant.
　ＣＰＵ６は、各負の乗算器Ｎ２０～Ｎ２４，Ｎ２６～Ｎ３０と正の乗算器Ｐ２５の係数を制御すると共に、乗算器２９で乗算される増幅値の正負及び増幅度を制御する。
　具体的には、ＣＰＵ６は、加算器２０からの出力が、補正対象ライン（３２Ｈ）の映像信号と、補正対象ラインから２の累乗数（ここでは、２，４，８，１６，３２）だけ離れたラインの映像信号との差分の合計となるよう、係数を制御する。
　また、本撮像装置のＣＰＵ６は、レンズ絞りを絞った場合の映像信号変調度の劣化を改善するために、レンズ絞り値に応じて輪郭補正信号のレベルを制御する。具体的には、レンズアイリスが絞り側になると、乗算器２９の係数を調整して、輪郭補正信号を増幅する制御を行う。 The CPU 6 controls the coefficients of each of the negative multipliers N20 to N24 and N26 to N30 and the positive multiplier P25, and controls the positive and negative values of the amplification value to be multiplied by the multiplier 29 and the amplification degree.
Specifically, the CPU 6 outputs only the video signal of the correction target line (32H) and the power of 2 from the correction target line (here, 2, 4, 8, 16, 32) from the adder 20 The coefficients are controlled so as to be the sum of the difference from the video signal of the distant line.
Further, the CPU 6 of the present imaging device controls the level of the contour correction signal according to the lens aperture value in order to improve the deterioration of the degree of modulation of the video signal when the lens aperture is narrowed. Specifically, when the lens iris is on the aperture side, the coefficient of the multiplier 29 is adjusted to control to amplify the contour correction signal.
　小振幅大振幅圧縮制限器（以下、制限器とする）３１は、差分加算信号が大振幅であれば圧縮し、小振幅の場合には圧縮を制限する。
　乗算器３２は、制限器３１からの出力に乗算器２９からの係数を乗算して、適切な極性及びレベルの垂直輪郭補正信号を生成する。
　補正信号加算部３３は、ラインメモリ部Ｍ２４から出力される補正対象ライン（３２Ｈ）に、垂直輪郭補正信号を加算して、垂直輪郭補正を行う。 A small amplitude / large amplitude compression limiter (hereinafter referred to as a limiter) 31 compresses if the differential addition signal has a large amplitude, and limits the compression if the differential addition signal has a small amplitude.
Multiplier 32 multiplies the output from limiter 31 by the coefficient from multiplier 29 to produce a vertical contour correction signal of appropriate polarity and level.
The correction signal addition unit 33 performs vertical contour correction by adding the vertical contour correction signal to the correction target line (32H) output from the line memory unit M24.
　このように、本撮像装置では、１画素間隔の周辺画素差分処理を行わないため、超低域の変調度を増強でき、高域変調度を相対的に低下させるものである。
　例えば、ＮＴＳＣ（National Television System Committee;全米テレビジョンシステム委員会）の０．５ＭＨｚを１００％として定義される５ＭＨｚ変調度や、２Ｋの飛越走査のＨＤＴＶの１ＭＨｚを１００％として定義される２７．５ＭＨｚ変調度等の高域変調度を相対的に低下させる。 As described above, in the present imaging device, since the peripheral pixel difference processing of one pixel interval is not performed, the modulation degree of the ultra low band can be enhanced, and the high band modulation degree is relatively decreased.
For example, 5 MHz modulation degree defined as 100% of 0.5 MHz of National Television System Committee (NTSC) or 27.5 MHz defined as 100% of 1 MHz of 2 K transit scan HDTV The high frequency modulation degree such as the modulation degree is relatively reduced.
［垂直輪郭補正部の動作：図２］
　本撮像装置の垂直輪郭補正部の動作について図２を用いて説明する。
　補正前信号は、負の乗算器Ｎ２０及びラインメモリ部Ｍ２０に入力され、ラインメモリ部Ｍ２０～Ｍ２９において、クロックのタイミングで、蓄積されると共に１ラインずつ負の乗算器Ｎ２１～Ｎ３０及び正の乗算器Ｐ２５に出力される。 [Operation of Vertical Contour Correction Unit: FIG. 2]
The operation of the vertical contour correction unit of the present imaging device will be described with reference to FIG.
The pre-correction signal is input to the negative multiplier N20 and the line memory unit M20, and is stored at the timing of the clock in the line memory units M20 to M29, and the negative multipliers N21 to N30 and the positive multiplication are added line by line. Is output to the receiver P25.
　具体的には、ラインメモリ部Ｍ２４から出力される補正対象ラインを３２Ｈとすると、負の乗算器Ｎ２０～Ｎ２４には、それぞれ、０Ｈ，１６Ｈ，２４Ｈ，３０Ｈが入力され、正の乗算器Ｐ２５にはＨ３２が入力され、負の乗算器Ｎ２６～Ｎ３０には、それぞれ３４Ｈ，３６Ｈ，４０Ｈ，４８Ｈ，６４Ｈが入力される。
　すなわち、補正対象ラインから２の累乗だけ離れたラインの映像信号が負の乗算器Ｎ２１～Ｎ２４，Ｎ２６～Ｎ３０に入力される。 Specifically, assuming that the correction target line output from the line memory unit M24 is 32H, 0H, 16H, 24H, and 30H are input to the negative multipliers N20 to N24, respectively, and the positive multiplier P25 is input to the negative multipliers N20 to N24. H32 is input to the negative multipliers N26 to N30, and 34H, 36H, 40H, 48H and 64H are input to the negative multipliers N26 to N30, respectively.
That is, the video signal of a line separated by a power of 2 from the correction target line is input to the negative multipliers N21 to N24 and N26 to N30.
　そして、各負の乗算器Ｎ２０～Ｎ２４、Ｎ２６～Ｎ３０、正の乗算器Ｐ２５において負又は正の係数が乗算され、加算器２０～２９で加算されて、補正対象ラインの映像信号と他のラインの映像信号との差分の合計が算出されて、加算器２０から差分加算信号として出力される。 Then, each of the negative multipliers N20 to N24 and N26 to N30 and the positive multiplier P25 are multiplied by a negative or positive coefficient, added by the adders 20 to 29, and the video signal of the correction target line and the other lines The sum of the differences with the video signal of the above is calculated, and is output from the adder 20 as a difference addition signal.
　差分加算信号は、制限器３１で振幅調整が施され、更に乗算器３２において映像レベルに応じた調整が為されて、垂直輪郭補正信号が生成され、補正信号加算部３３において、補正対象ラインの映像信号と垂直輪郭補正信号とが加算されて、垂直方向の輪郭補正が行われる。
　このようにして垂直輪郭補正部の動作が行われるものである。 The differential addition signal is subjected to amplitude adjustment by the limiter 31 and further adjusted according to the video level by the multiplier 32 to generate a vertical contour correction signal, and the correction signal addition unit 33 generates the correction target line. The video signal and the vertical contour correction signal are added to perform contour correction in the vertical direction.
In this manner, the operation of the vertical contour correction unit is performed.
　尚、本実施の形態においては、垂直方向に３２画素間隔までの差分の合計に基づいて垂直輪郭補正信号を生成するようにしているが、６４画素間隔や１２８画素間隔の差分の合計を求めて垂直輪郭補正信号を生成してもよい。 In the present embodiment, the vertical contour correction signal is generated based on the sum of the differences up to the 32 pixel interval in the vertical direction, but the sum of the differences of the 64 pixel interval and the 128 pixel interval is calculated A vertical contour correction signal may be generated.
［水平輪郭補正部の構成：図３］
　次に、本撮像装置の特徴部分である、水平輪郭補正部の構成について図３を用いて説明する。図３は、本撮像装置の水平輪郭補正部の構成図である。
　水平輪郭補正部は、水平方向に配列された画素間の映像信号を比較して、水平方向の輪郭を補正するものである。
　図３に示すように、水平輪郭補正部は、複数の画素遅延部Ｄ４０～Ｄ４９と、複数の負の乗算器Ｎ４０～Ｎ４４及びＮ４６～Ｎ５０と、正の乗算器Ｐ４５と、複数の加算器４０～４９と、映像レベル判定器５１と、乗算器５２，５４と、小振幅大振幅圧縮制限器５３と、補正信号加算部５５とを備えている。 [Configuration of Horizontal Contour Correction Unit: FIG. 3]
Next, the configuration of the horizontal contour correction unit, which is a characteristic part of the present imaging device, will be described with reference to FIG. FIG. 3 is a configuration diagram of a horizontal contour correction unit of the present imaging device.
The horizontal contour correction unit corrects the horizontal contour by comparing video signals between pixels arranged in the horizontal direction.
As shown in FIG. 3, the horizontal contour correction unit includes a plurality of pixel delay units D40 to D49, a plurality of negative multipliers N40 to N44 and N46 to N50, a positive multiplier P45, and a plurality of adders 40. To 49, an image level determination unit 51, multipliers 52 and 54, a small amplitude / large amplitude compression limiter 53, and a correction signal addition unit 55.
　つまり、水平輪郭補正部は、図２に示した垂直輪郭補正部のラインメモリ部Ｍ２０～Ｍ２９の代わりに、画素遅延部Ｄ４０～Ｄ４９が設けられ、水平方向に配列された画素について処理を行う点が異なるが、その他の基本的な構成及び動作は垂直輪郭補正部と同等であるため、詳細な説明は省略する。 That is, the horizontal contour correction unit is provided with pixel delay units D40 to D49 instead of the line memory units M20 to M29 of the vertical contour correction unit shown in FIG. 2, and performs processing on pixels arranged in the horizontal direction. However, the other basic configuration and operation are the same as those of the vertical contour correction unit, and therefore detailed description will be omitted.
　そして、水平輪郭補正部では、補正対象画素の映像信号と、当該補正対象画素から水平方向に２，４，８，１６，３２画素だけ離れた画素の映像信号との差分の合計が加算器４０から加算差分信号として出力され、小振幅大振幅圧縮制限器５３において、加算差分信号の振幅補正が行われ、映像レベル判定器５１での判定結果に基づいて乗算器５４で調整されて水平輪郭補正信号が生成され、補正信号加算部５５において、補正対象画素（３２ｄ）の映像信号と水平輪郭補正信号とが加算されて、水平方向の輪郭補正が行われる。 Then, in the horizontal contour correction unit, the sum of the difference between the video signal of the correction target pixel and the video signal of the pixel separated by 2, 4, 8, 16, 32 pixels in the horizontal direction from the correction target pixel is the adder 40. The signal is output as an addition difference signal from the above, and amplitude correction of the addition difference signal is performed in the small amplitude / large amplitude compression limiter 53, and is adjusted by the multiplier 54 based on the determination result in the video level determination unit 51 to correct horizontal contour. A signal is generated, and the video signal of the correction target pixel (32d) and the horizontal contour correction signal are added in the correction signal addition unit 55 to perform contour correction in the horizontal direction.
　水平方向の輪郭補正においても、１画素間隔の周辺画素差分処理を行わないため、超低域の変調度を増強でき、高域変調度を相対的に低下させるものである。 Also in the contour correction in the horizontal direction, peripheral pixel difference processing of one pixel interval is not performed, so that the modulation factor of the ultra low band can be enhanced, and the high band modulation factor is relatively lowered.
［本撮像装置における差分加算信号の例：図４］
　ここで、本撮像装置における差分加算信号の例について図４を用いて説明する。図４は、２，４，８，１６画素間隔の差分加算信号の周波数軸表示である。
　図２を例として説明すると、図４（ａ）に示す２画素間隔の差分加算信号は、正の乗算器Ｐ２５と、負の乗算器Ｎ２４及びＮ２６に０（ゼロ）以外の係数が設定され、他の負の乗算器には係数０が設定された状態で、加算器４０から得られる差分加算信号である。 [Example of a differential addition signal in the present imaging device: FIG. 4]
Here, an example of the differential addition signal in the present imaging device will be described with reference to FIG. FIG. 4 is a frequency axis display of differential addition signals at intervals of 2, 4, 8, and 16 pixels.
Referring to FIG. 2 as an example, in the differential addition signal of 2-pixel intervals shown in FIG. 4A, coefficients other than 0 (zero) are set in the positive multiplier P25 and the negative multipliers N24 and N26. The other negative multiplier is a differential addition signal obtained from the adder 40 with the coefficient 0 set.
　同様に、図４（ｂ）に示す４画素間隔の差分加算信号は、２画素間隔の場合に加えて、負の乗算器Ｎ２３とＮ２７が０以外の係数となった場合の差分加算信号であり、８画素間隔の差分加算信号は、更に負の乗算器Ｎ２２とＮ２８に０以外の係数が設定され、１６画素間隔の差分加算信号は、更に負の乗算器Ｎ２１とＮ２９にも０以外の係数が設定された場合の差分加算信号である。 Similarly, the differential addition signal of 4-pixel intervals shown in FIG. 4B is a differential addition signal when the negative multipliers N23 and N27 become coefficients other than 0 in addition to the 2-pixel interval. For the differential addition signal at intervals of 8 pixels, coefficients other than 0 are set to the negative multipliers N22 and N28, and the differential addition signals at intervals of 16 pixels are coefficients other than 0 for the negative multipliers N21 and N29. Is a differential addition signal when is set.
　図４に示すように、本撮像装置の差分加算信号は、いずれも、雑音も含めてｆｓ／２付近の高周波成分がないため、低周波数（低域）の変調度を改善した映像信号を出力することができるものである。
　そのため、入力信号が変調度の低い状態であっても、被写界深度の浅い望遠端での焦点合わせを容易にすることができるものである。 As shown in FIG. 4, all differential addition signals of the present imaging apparatus output no video signal with improved modulation of low frequency (low frequency) because there is no high frequency component near fs / 2 including noise. It is something that can be done.
Therefore, even when the input signal has a low degree of modulation, focusing at a telephoto end with a shallow depth of field can be facilitated.
［本撮像装置における輪郭補正：図５］
　本撮像装置における輪郭補正信号及び輪郭補正後の信号例について図５を用いて説明する。図５は、本撮像装置の輪郭補正信号及び輪郭補正後の信号例を示す模式説明図である。
　図５（ａ）は、補正前信号、（ｂ）は、１７Ｈ成分／１７画素成分（８画素間隔）の差分加算信号に基づく輪郭補正信号、（ｃ）は、９Ｈ成分／９画素成分（４画素間隔）の差分加算信号に基づく輪郭補正信号、（ｄ）は、７Ｈ成分／７画素成分（３画素間隔）の差分加算信号に基づく輪郭補正信号、（ｅ）は、５Ｈ成分／５画素成分（２画素間隔）の差分加算信号に基づく輪郭補正信号、（ｆ）は、３Ｈ成分／３画素成分（１画素間隔）の差分加算信号に基づく輪郭補正信号、（ｇ）は、１７Ｈ９Ｈ５Ｈ成分／１７画素９画素５画素成分（８画素４画素２画素間隔）の輪郭補正信号による輪郭補正後の信号、（ｈ）は、９Ｈ５Ｈ成分／９画素５画素成分（４画素２画素間隔）の輪郭補正信号による輪郭補正後の信号を示している。
　ここで、（ｄ）と（ｆ）は、本撮像装置では生成されない信号であるが、参考のために示している。 [Contour correction in this imaging device: FIG. 5]
A contour correction signal in the present imaging device and a signal example after contour correction will be described with reference to FIG. FIG. 5 is a schematic explanatory view showing a contour correction signal of the present imaging device and a signal example after contour correction.
FIG. 5 (a) shows a signal before correction, FIG. 5 (b) shows an edge correction signal based on a difference addition signal of 17H component / 17 pixel components (eight pixel intervals), and FIG. 5C shows 9H component / 9 pixel components (4 (D) is a contour correction signal based on a 7H component / 7 pixel component (3 pixel interval) differential addition signal, and (e) is a 5H component / 5 pixel component. A contour correction signal based on a differential addition signal of (two pixel intervals), (f) is a contour correction signal based on a differential addition signal of 3H component / 3 pixel components (one pixel interval), and (g) is 17H9H5H component / 17 (H) is a contour correction signal of 9H5H component / 9 pixels 5 pixel components (4 pixels 2 pixels interval) after contour correction with contour correction signal of 9 pixels 5 pixels 5 pixels component (8 pixels 4 pixels 2 pixels interval) Shows the signal after contour correction by.
Here, (d) and (f) are signals that are not generated by the present imaging device, but are shown for reference.
　（ｇ）の信号は、（ｂ）の８画素間隔の差分加算信号と、（ｃ）の４画素間隔の差分加算信号と、（ｅ）の２画素間隔の差分加算信号との合計に基づいて生成された輪郭補正信号と、（ａ）の補正前信号とを加算して得られる信号である。
　（ｇ）に示した輪郭補正後の信号は、例えば、１７Ｈ１５Ｈ１３Ｈ１１Ｈ９Ｈ７Ｈ５Ｈ３Ｈ輪郭補正信号（１７Ｈ１５Ｈ１３Ｈ１１Ｈ９Ｈ７Ｈ５Ｈ３Ｈ成分／１７画素１５画素１３画素１１画素９画素７画素５画素３画素成分の差分加算信号に基づく輪郭補正信号）で補正した場合と比べると、高周波数成分の細かい輪郭を再生できないものの、高域雑音が少ないので、輪郭補正信号を大きくすることができ、強く輪郭補正でき、輪郭を十分明瞭にすることができるものである。 The signal of (g) is based on the sum of the differential addition signal of 8-pixel intervals of (b), the differential addition signal of 4-pixel intervals of (c), and the differential addition signal of 2-pixel intervals of (e). This is a signal obtained by adding the generated contour correction signal and the pre-correction signal of (a).
The signal after contour correction shown in (g) is, for example, a 17H15H13H11H9H7H5H3H contour correction signal (a contour correction signal based on a difference addition signal of 17H15H13H11H9H9H7H5H3H component / 17 pixels 15 pixels 13 pixels 11 pixels 9 pixels 5 pixels 3 pixels component) Compared to the case where correction is made with the above, although the fine contours of high frequency components can not be reproduced, the high frequency noise is small, so the contour correction signal can be enlarged, the contour can be strongly corrected, and the contour can be made sufficiently clear. It is a thing.
　また、（ｈ）の信号は、（ｃ）の４画素間隔の差分加算信号と、（ｅ）の２画素間隔の差分加算信号との合計に基づいて生成された輪郭補正信号と、（ａ）の補正前信号とを加算して得られる信号である。
　（ｈ）の輪郭補正後の信号は、例えば、９Ｈ７Ｈ５Ｈ３Ｈ輪郭補正信号（９Ｈ７Ｈ５Ｈ３Ｈ成分／９画素７画素５画素３画素成分の差分加算信号に基づく輪郭補正信号）で補正した場合と比べると、高周波成分の細かい輪郭を再生できないが、高域雑音が少ないので、輪郭補正信号を大きくすることができ、輪郭を明瞭にすることができるものである。 Also, the signal of (h) is a contour correction signal generated based on the sum of the differential addition signal of 4-pixel intervals of (c) and the differential addition signal of 2-pixel intervals of (e), (a) It is a signal obtained by adding the pre-correction signal of
The signal after contour correction in (h) is, for example, a high frequency component as compared with the case where it is corrected with a 9H7H5H3H contour correction signal (a contour correction signal based on a differential addition signal of 9H7H5H3H component / 9 pixels 7 pixels 5 pixels 3 pixel components) Although it is not possible to reproduce fine outlines of the image, the outline correction signal can be enlarged because the high frequency noise is small, and the outlines can be made clear.
　そのため、望遠端における開放絞り値が、画素ピッチ／撮像光の中心波長の値より大きいレンズ、又は収差が大きいレンズなど、低周波数において変調度が低い特性を有するレンズを用いた場合にも、被写界深度の浅い望遠端での焦点合わせを容易にすることができるものである。 Therefore, even when using a lens having a low modulation factor at low frequencies, such as a lens whose open aperture value at the telephoto end is larger than the pixel pitch / the value of the central wavelength of imaging light, or a lens having a large aberration, It is possible to facilitate focusing at a telephoto end with a shallow depth of field.
　したがって、図７に示した、アスペクト比１６：９の撮像素子のサイズとレンズの口径比による変調度の変化のように、口径比Ｆの超望遠ズームレンズの変調度が低下しても、輪郭補正が容易になる。 Therefore, as shown in FIG. 7, even if the modulation factor of the super telephoto zoom lens with the aperture ratio F decreases, as in the case of the change of the modulation factor due to the size of the imaging device with an aspect ratio of 16: 9 and the aperture ratio of the lens shown in FIG. Correction becomes easy.
［実施の形態の効果］
　本発明の実施の形態に係る撮像装置によれば、画素間隔が５波長以下のＣＭＯＳ撮像素子を用いた撮像装置において、輪郭補正部１１が、輪郭補正を施す補正対象の画素の映像信号と、補正対象画素と２の累乗の画素間隔（２，４，８，１８，３２等）となる複数の画素の映像信号との差分をそれぞれ算出し、当該複数の差分を加算した差分加算信号に基づいて輪郭補正信号を生成し、補正信号加算部が、補正対象画素の映像信号に輪郭補正信号を加算するようにしているので、ｆｓ／２付近の高周波成分が含まれない輪郭補正信号を生成でき、低域の輪郭補正信号を補強して、低域におけるＭＴＦを改善し、被写界深度の浅い望遠レンズの望遠端においても焦点合わせを容易にすることができる効果がある。 [Effect of the embodiment]
According to the image pickup apparatus of the embodiment of the present invention, in the image pickup apparatus using the CMOS image pickup element having a pixel interval of 5 wavelengths or less, the contour correction unit 11 generates an image signal of a pixel to be corrected. The difference between the correction target pixel and the video signal of a plurality of pixels having a pixel interval (2, 4, 8, 18, 32, etc.) of powers of 2 is calculated, and the difference is added based on the difference. The contour correction signal is generated, and the correction signal addition unit adds the contour correction signal to the video signal of the pixel to be corrected, so that a contour correction signal that does not include high frequency components near fs / 2 can be generated. There is an effect that the low-range contour correction signal can be reinforced to improve the MTF in the low range, and focusing can be facilitated even at the telephoto end of a telephoto lens with a shallow depth of field.
　また、本撮像装置では、補償対象画素と、２，４，８，１６，３２画素間隔となる画素との差分の合計を算出しているが、６４画素、１２８画素等、より多くのラインメモリ部又は画素遅延部、乗算器、加算器を備えた構成としてもよく、多いほど輪郭補正の効果は大きくなるため、回路規模が許容されるならば、多くすることが望ましい。
　また、映像レベル判定器出力信号が小信号大振幅圧縮制限器から出力する輪郭補正信号レベルを制御することから、レンズ絞り値に応じて映像レベル判定器出力信号レベルを制御することにより輪郭補正信号レベルを制御することも容易となる。 Further, in the present imaging device, the sum of the difference between the pixel to be compensated and the pixel having an interval of 2, 4, 8, 16, 32 pixels is calculated, but more line memories such as 64 pixels, 128 pixels, etc. It is also possible to use a configuration provided with a section or pixel delay section, a multiplier, and an adder, and the effect of contour correction increases as the number increases, so it is desirable to increase if the circuit scale is acceptable.
In addition, since the video level discriminator output signal controls the contour correction signal level output from the small signal large amplitude compression limiter, the contour correction signal is controlled by controlling the video level discriminator output signal level according to the lens aperture value. It also becomes easy to control the level.
　６４画素間隔の差分を加えて輪郭補正信号を生成すれば、例えば、２Ｋの飛越操作のＨＤＴＶの０．５ＭＨｚ変調度を改善することができ、更に１２８画素間隔の差分を加えれば、２Ｋの飛越操作のＨＤＴＶの０．２５ＭＨｚの変調度を改善することができる効果がある。 If a difference of 64 pixel intervals is added to generate a contour correction signal, for example, the 0.5 MHz modulation factor of HDTV of 2K jump operation can be improved, and if a difference of 128 pixel intervals is further added, 2K jumps There is an effect that it is possible to improve the modulation degree of 0.25 MHz of operation HDTV.
　また、監視用１／３型ＨＤ２Ｋ撮像素子と、報道用２／３型４Ｋ撮像素子と、中継用４／３型８Ｋ撮像素子は、２．５μｍの同一画素間隔となっており、超望遠での収差が大きく、絞りが暗く、ＭＴＦが低い状態になるが、本装置によれば、それらの特性を許容して、低周波でのＭＴＦを改善することができ、撮像装置の低価格化を実現できる効果がある。
　つまり、本装置は、高価で大型の低域ＭＴＦの高いＵＨＤＴＶレンズを使用することなく、電子的に補正することにより、低コストで輪郭強調を可能とする効果がある。 In addition, the monitoring 1 / 3-type HD2K imaging device, the reporting 2 / 3-type 4K imaging device, and the relay 4 / 3-type 8K imaging device have the same pixel interval of 2.5 μm, and are super telephoto. The aberration is large, the diaphragm is dark, and the MTF is low. However, according to this device, these characteristics can be allowed to improve the MTF at low frequency, and the price of the imaging device can be reduced. There is an effect that can be realized.
That is, the present apparatus has an effect of enabling outline emphasis at low cost by performing electronic correction without using an expensive large-sized low-pass MTF high UHDTV lens.
　更に、本装置によれば、監視用１／３型ＨＤ２Ｋカメラや４Ｋカメラや８Ｋカメラの拡販だけではなく、放送局や中継会社が多数保有している２Ｋカメラのファームウェアバージョンアップによる画質向上にも活用することができる効果がある。 Furthermore, according to this device, not only sales expansion of surveillance 1/3 type HD2K cameras, 4K cameras and 8K cameras, but also image quality improvement by upgrading firmware versions of 2K cameras owned by many broadcast stations and relay companies There is an effect that can be utilized.
　本発明は、高周波数成分のない輪郭補正を行うことにより、低周波数における変調度を改善した映像信号を出力できる撮像装置に適している。この出願は、２０１７年９月２５日に出願された日本出願特願２０１７－１８３３３８を基礎として優先権の利益を主張するものであり、その開示の全てを引用によってここに取り込む。 The present invention is suitable for an imaging apparatus capable of outputting a video signal with an improved degree of modulation at low frequencies by performing contour correction without high frequency components. This application claims the benefit of priority based on Japanese Patent Application No. 2017-183338 filed on Sep. 25, 2017, the entire disclosure of which is incorporated herein by reference.
　１…撮像装置、　２…色分解光学系、　３，３Ｒ，３Ｇ，３Ｂ…撮像素子、　４…映像信号処理部、　５…パラレル／シリアル変換部、　６…ＣＰＵ、　７…レンズ、　８…ビューファインダー、　１１…輪郭補正部、　１２…ガンマ色補正部、　１３…ＭＡＴＲＩＸ部、　Ｍ２０～Ｍ２９…ラインメモリ部、　Ｎ２０～Ｎ２４，Ｎ２６～Ｎ３０，Ｎ４０～Ｎ４４，Ｎ４６～Ｎ５０…負の乗算器、　Ｐ２５，Ｐ４５…正の乗算器、　２０～２９，４０～４９…加算器、　２８，５１…映像レベル判定器、　２９，３０，５２，５４…乗算器、　３１，５３…小振幅大振幅圧縮制限器、　３３，５５…補正信号加算部、　Ｄ４０～Ｄ４９…画素遅延部、　９１…マイクロレンズ、　９２…カラーフィルタ、　９３…フォトダイオード、　９４…メタル配線層 DESCRIPTION OF SYMBOLS 1 ... Imaging device, 2 ... color separation optical system, 3, 3R, 3G, 3B ... Imaging device, 4 ... Video signal processing part, 5 ... Parallel / serial conversion part, 6 ... CPU, 7 ... Lens, 8 ... Viewfinder 11 Contour correction unit 12 Gamma color correction unit 13 MATRIX unit M20 to M29 Line memory unit N20 to N24 N26 to N30 N40 to N44 N46 to N50 Negative multiplier P25 P45: Positive multiplier, 20 to 29, 40 to 49: Adder, 28, 51: Video level determiner, 29, 30, 52, 54: Multiplier, 31, 53: Small amplitude, large amplitude compression limiter, 33, 55 ... correction signal addition unit, D40 to D49 ... pixel delay unit, 91 ... microlens, 92 ... color filter, 93 ... photodiode, 94 Metal wiring layer

Claims (5)

  1. 　画素ピッチが撮像光の中心波長の５倍以下であるＣＭＯＳ撮像素子を用いた撮像装置であって、
    　前記撮像素子を備え、入力光を色毎に分解して映像信号を出力する色分解部と、
    　前記色分解部からの映像信号について、輪郭補正を施す補正対象の画素の映像信号と、当該補正対象の画素から２の累乗の画素間隔となる複数の画素の映像信号との差分を算出し、当該複数の差分を加算した差分加算信号に基づいて輪郭補正信号を生成し、前記補正対象画素の映像信号に前記輪郭補正信号を加算して輪郭補正を行う輪郭補正部を備えたことを特徴とする撮像装置。     An imaging apparatus using a CMOS imaging device having a pixel pitch equal to or less than five times the central wavelength of imaging light,
    A color separation unit that includes the image pickup element and separates input light into each color to output a video signal;
    With respect to the video signal from the color separation unit, the difference between the video signal of the pixel to be corrected to be subjected to contour correction and the video signal of a plurality of pixels having pixel intervals of a power of 2 from the pixel to be corrected is calculated. A contour correction unit is provided, which generates a contour correction signal based on a difference addition signal obtained by adding the plurality of differences, adds the contour correction signal to the video signal of the correction target pixel, and performs contour correction. Imaging device.
  2. 　輪郭補正部が、補正対象の画素の映像信号と、前記補正対象の画素から２の累乗の画素間隔となる複数の画素の映像信号との差分を算出し、当該複数の差分を加算して差分加算信号を生成する差分加算部と、
    　前記差分加算信号を、前記補正対象の画素の映像信号レベルに基づいて調整して前記補正対象の画素に対応する輪郭補正信号を生成する輪郭補正信号生成部と、
    　前記補正対象の画素の映像信号に前記輪郭補正信号を加算する輪郭補正信号加算部とを備えたことを特徴とする請求項１記載の撮像装置。     The contour correction unit calculates a difference between the video signal of the pixel to be corrected and the video signal of the plurality of pixels which is a pixel interval of a power of 2 from the pixel to be corrected, adds the plurality of differences and calculates a difference A differential addition unit that generates an addition signal;
    A contour correction signal generation unit which adjusts the difference addition signal based on the video signal level of the pixel to be corrected to generate a contour correction signal corresponding to the pixel to be corrected;
    The image pickup apparatus according to claim 1, further comprising: a contour correction signal addition unit that adds the contour correction signal to the video signal of the pixel to be corrected.
  3. 　２の累乗の画素間隔を、２画素間隔から３２画素間隔までとすることを特徴とする請求項１又は２記載の撮像装置。 The image pickup apparatus according to claim 1 or 2, wherein the pixel interval of the power of 2 is from 2 pixel intervals to 32 pixel intervals.
  4. 　撮像素子を表面照射型のＣＭＯＳ撮像素子としたことを特徴とする請求項１乃至３のいずれか記載の撮像装置。 The imaging device according to any one of claims 1 to 3, wherein the imaging device is a surface-illuminated CMOS imaging device.
  5. 　望遠端の開放絞り値が、撮像素子の画素ピッチ／中心波長より大きいレンズ、又は収差の大きいレンズから入力される映像信号について、輪郭補正を行うことを特徴とする請求項１乃至４のいずれか記載の撮像装置。 5. The contour correction is performed on an image signal input from a lens having an aperture value at the telephoto end larger than a pixel pitch of the image pickup element / center wavelength or a lens having a large aberration. The imaging device of description.
PCT/JP2018/032987 2017-09-25 2018-09-06 Imaging device WO2019058980A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
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JP2004260421A (en) * 2003-02-25 2004-09-16 Fujitsu General Ltd Contour correction circuit
WO2015129120A1 (en) * 2014-02-26 2015-09-03 富士フイルム株式会社 Method for manufacturing image-capturing module, and device for manufacturing image-capturing module
WO2016152343A1 (en) * 2015-03-20 2016-09-29 株式会社日立国際電気 Image-capture device and image-capture method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004260421A (en) * 2003-02-25 2004-09-16 Fujitsu General Ltd Contour correction circuit
WO2015129120A1 (en) * 2014-02-26 2015-09-03 富士フイルム株式会社 Method for manufacturing image-capturing module, and device for manufacturing image-capturing module
WO2016152343A1 (en) * 2015-03-20 2016-09-29 株式会社日立国際電気 Image-capture device and image-capture method

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