Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/70—Circuitry for compensating brightness variation in the scene
  • H04N23/73—Circuitry for compensating brightness variation in the scene by influencing the exposure time
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
  • H04N25/50—Control of the SSIS exposure
  • H04N25/53—Control of the integration time
  • H04N25/533—Control of the integration time by using differing integration times for different sensor regions
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
  • H04N25/50—Control of the SSIS exposure
  • H04N25/57—Control of the dynamic range
  • H04N25/58—Control of the dynamic range involving two or more exposures
  • H04N25/581—Control of the dynamic range involving two or more exposures acquired simultaneously
  • H04N25/583—Control of the dynamic range involving two or more exposures acquired simultaneously with different integration times
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
  • H04N25/50—Control of the SSIS exposure
  • H04N25/57—Control of the dynamic range
  • H04N25/58—Control of the dynamic range involving two or more exposures
  • H04N25/581—Control of the dynamic range involving two or more exposures acquired simultaneously
  • H04N25/585—Control of the dynamic range involving two or more exposures acquired simultaneously with pixels having different sensitivities within the sensor, e.g. fast or slow pixels or pixels having different sizes
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
  • H04N25/50—Control of the SSIS exposure
  • H04N25/57—Control of the dynamic range
  • H04N25/58—Control of the dynamic range involving two or more exposures
  • H04N25/587—Control of the dynamic range involving two or more exposures acquired sequentially, e.g. using the combination of odd and even image fields
  • H04N25/589—Control of the dynamic range involving two or more exposures acquired sequentially, e.g. using the combination of odd and even image fields with different integration times, e.g. short and long exposures

Definitions

• Imaging apparatus imaging method, and imaging program
• the present invention relates to an imaging apparatus used for a video camera or the like, and particularly to a technique for expanding a dynamic range.
• Japanese Patent Laid-Open No. 5-64083 discloses such an imaging apparatus.
• pixels (photodiodes) provided with a filter and! / ⁇ ⁇ ⁇ ⁇ pixels (photodiodes) not provided with a filter are arranged every other row.
• This conventional imaging apparatus is configured so that the exposure amount of a pixel differs by providing a difference in pixel sensitivity using a filter, and image signals having different exposure amounts even in one exposure. can get.
• the image signals with different exposure amounts obtained in this way are combined to expand the dynamic range of the image signal.
• the conventional imaging apparatus is configured to provide a difference in pixel sensitivity using a filter so that the exposure amount of the pixel is different. Therefore, in order to change the ratio of the exposure amount of a pixel with a filter and a pixel without a filter, the filter must be replaced. In other words, it is difficult for the conventional imaging device to change the ratio of pixel exposure amounts. Therefore, when shooting a subject with a large difference in brightness, it is difficult to adjust the ratio of the exposure amounts of the pixels according to the degree of the difference in brightness of the subject. For example, when an imaging device is used as a surveillance camera or the like, it is not suitable for photographing a subject with a large difference in brightness.
• the present invention has been made under the above background.
• the object of the present invention is to adjust the exposure time for each pixel group, and to adjust the dynamics according to the difference in brightness of the subject.
• An object of the present invention is to provide an image pickup apparatus capable of expanding the range of a signal.
• One aspect of the present invention is an imaging device.
• the imaging device all pixels are divided into a long exposure pixel group and a short exposure pixel group, and a predetermined frame is formed from the pixels of each pixel group.
• the long-exposure pixel group power is stored for a long time with the imaging unit that can read the accumulated charge signals with different exposure times within the period and the first readout timing after the long exposure period elapses within the frame period.
• the first readout unit that reads out the charge signal and the second readout timing after the short exposure period has elapsed within the frame period, read out the accumulated charge signal of the short exposure pixel group force and the second readout.
• Short-time exposure using the long-time exposure signal generation unit that generates a long-time exposure signal using the long-time exposure accumulated charge signal and the short-time exposure pixel group force A short-time exposure signal generating unit that generates a signal; and a combining unit that combines the long-time exposure signal and the short-time exposure signal to generate a video signal for all pixels.
• Another aspect of the present invention is an imaging method, in which all pixels are divided into a long exposure pixel group and a short exposure pixel group, and a predetermined frame is formed from the pixels of each pixel group.
• an imaging unit that can read stored charge signals with different exposure times within the period, the first readout timing after the long exposure period has elapsed within the frame period, and the short exposure period has elapsed within the frame period
• the second readout timing is adjusted independently, the accumulated charge signal of the long exposure is read from the long exposure pixel group at the first readout timing, and the second readout timing is shortened at the second readout timing.
• Time Accumulated charge signal of short exposure is read from the exposure pixel group, and long exposure pixel group force The long exposure signal is read using the stored charge signal of long exposure.
• a short-time exposure signal is generated using the short-time exposure accumulated charge signal read from the short-time exposure pixel group, and the long-time exposure signal and the short-time exposure signal are combined to generate all the pixel components.
• Video signal is generated.
• Another aspect of the present invention is a shooting program. In the shooting program, all pixels are divided into a long-exposure pixel group and a short-exposure pixel group, and a predetermined number of pixels are determined from the pixels of each pixel group.
• the first readout timing and the second readout timing after the short exposure period elapses within the frame period can be adjusted independently, and the long exposure pixel group can be adjusted to the computer at the first readout timing. Stored in the short-time exposure pixel group from the short-exposure pixel group in the procedure for reading out the long-time exposure accumulated charge signal from the second readout timing.
• the procedure for reading the signal, the procedure for generating the long exposure signal using the accumulated charge signal for the long exposure read from the long exposure pixel group, and the accumulation of the short exposure read from the short exposure pixel group A procedure for generating a short exposure signal using the charge signal and a procedure for generating a video signal for all pixels by combining the long exposure signal and the short exposure signal are executed.
• FIG. 1 is a block diagram of an imaging apparatus according to a first embodiment of the present invention.
• FIG. 2 is a block diagram of the image pickup device of the image pickup apparatus according to the first embodiment of the present invention.
• FIG. 3 is a block diagram of the image pickup element of the image pickup device according to the first embodiment of the present invention.
• FIG. 4 is an explanatory diagram of the pixel arrangement of the image sensor of the imaging device according to the first embodiment of the present invention.
• FIG. 5 is an explanatory diagram of the timing of the operation of the imaging apparatus according to the first embodiment of the present invention.
• FIG. 6 is an explanatory diagram of the operation of the image sensor of the image pickup apparatus according to the first embodiment of the present invention.
• FIG. 7 shows the operation of the time axis converter of the imaging device according to the first embodiment of the present invention. Illustration of
• FIG. 8 is a block diagram of the image sensor of the image pickup apparatus according to the second embodiment of the present invention.
• FIG. 9 is a block diagram of the image sensor of the image pickup apparatus according to the second embodiment of the present invention.
• Explanatory diagram [FIG. 10] FIG. 10 is an explanatory diagram of the timing of the operation of the imaging apparatus in the second embodiment of the present invention.
• FIG. 11 is an explanatory diagram of the operation of the image sensor of the imaging device according to the second embodiment of the present invention.
• Fig. 12 is an explanatory diagram of the timing of the operation of the image pickup apparatus in the third embodiment of the present invention.
• FIG. 13 is an explanatory diagram of a pixel arrangement of an image pickup element of an image pickup apparatus according to another embodiment.
• FIG. 14A is an explanatory diagram of a pixel arrangement when they are alternately arranged for each column.
• FIG. 14B is an explanatory diagram of pixel arrangement when they are arranged alternately for each row.
• FIG. 14C is an explanatory diagram of pixel arrangement when alternately arranged for each pixel.
• FIG. 14D is an explanatory diagram of pixel arrangement when two pixels are alternately arranged.
• all pixels are divided into a long exposure pixel group and a short exposure pixel group, and accumulated charge signals having different exposure times within a predetermined frame period from pixels of each pixel group.
• a readable image pickup unit, and a first readout unit that reads out a long-exposure accumulated charge signal from a long-exposure pixel group at a first readout timing after a long exposure period has elapsed within a frame period;
• the short-time exposure that generates the short-time exposure signal using the long-time exposure signal generator that generates the long-time exposure signal and the accumulated charge signal of the short-time exposure pixel dull force read out
• the exposure time (long exposure period) of the pixels in the long exposure pixel group can be easily changed by changing the first readout timing.
• the exposure time (short exposure period) of the pixels of the short exposure pixel group can be easily changed.
• the first readout timing and the second readout timing respectively, the exposure time can be adjusted for each pixel group, and the dynamic range is expanded according to the degree of difference in brightness of the subject.
• This force S is possible. For example, when shooting a subject with a large difference between light and dark, it is possible to use the force S to expand the dynamic range by adjusting the long exposure period and shortening the short exposure period.
• the imaging apparatus of the present invention includes a third readout unit that reads out a long-time exposure accumulated charge signal from a short-time exposure pixel group at a first readout timing within a frame period, and includes a long-time exposure signal.
• the creation unit reads the long-time exposure accumulated charge signal read from the short-time exposure pixel group and the long-time exposure pixel data read from the long-time exposure pixel group. It can be added to the accumulated charge signal to generate a long exposure signal.
• the imaging apparatus of the present invention includes a fourth readout unit that reads out the accumulated charge signal of the short-time exposure from the long-time exposure pixel group at the second readout timing within the frame period, and includes the long-time exposure signal.
• the creation unit adds the short-time exposure accumulated charge signal read from the long-exposure pixel group to the long-exposure accumulated charge signal read from the long-exposure pixel group to generate a long-exposure signal. You have.
• the pixels of the long exposure pixel group and the pixels of the short exposure pixel group may have a configuration in which the pixels are alternately arranged in the vertical direction or the horizontal direction.
• the pixels of the long-time exposure pixel group and the pixels of the short-time exposure group are arranged without deviation in the vertical direction or the horizontal direction. Therefore, when all the pixels are divided into two pixel groups (long exposure pixel group and short exposure group), it is possible to suppress the occurrence of resolution bias in each pixel group.
• the imaging device of the present invention may have a configuration in which pixels are arranged so that the pixel arrangement is a Bayer arrangement in each of the long-exposure pixel group and the short-exposure pixel group. .
• the accumulated charge signals read from the long exposure pixel group and the short exposure pixel group become Payer array signals, so the long exposure signal and the short exposure signal generated from these accumulated charge signals.
• Image processing can be easily performed by general signal processing (signal processing for primary color bayers).
• the first readout unit includes a first transfer path connected to each pixel of the long exposure pixel group, and a first transfer from each pixel of the long exposure pixel group.
• a first gate electrode serving as a readout path to the path
• the second readout unit includes a second transfer path connected to each pixel of the short exposure pixel group and each pixel of the short exposure pixel group.
• the read timing adjustment unit applies a gate voltage to the first gate electrode at the first read timing, and at the second read timing.
• a structure in which a gate voltage is applied to the second gate electrode may be employed.
• the third readout unit includes a first transfer path connected to each pixel of the short-time exposure pixel group, and a first transfer from each pixel of the short-time exposure pixel group.
• a third gate electrode serving as a read path to the path may be provided, and the read timing adjustment unit may be configured to apply a gate voltage to the third gate electrode at the first read timing.
• the fourth readout unit includes a first transfer path connected to each pixel of the long exposure pixel group, and a first transfer from each pixel of the long exposure pixel group.
• a first gate electrode serving as a read path to the path may be provided, and the read timing adjustment unit may be configured to apply a gate voltage to the first gate electrode at the second read timing.
• all pixels have long exposure pixel groups and short exposure pixel dulls.
• the first image after the long exposure period has elapsed within the frame period using an imaging unit that is capable of reading out accumulated charge signals with different exposure times within a predetermined frame period from the pixels of each pixel group.
• the readout timing and the second readout timing after the short exposure period within the frame period are adjusted independently, and at the first readout timing, the long-exposure pixel group force is also stored in the long-exposure accumulated charge signal.
• the second readout timing read the short-exposure accumulated charge signal from the short-exposure pixel group, and use the long-exposure accumulated charge signal read from the long-exposure pixel group.
• the short-time exposure signal is generated using the short-time exposure accumulated charge signal read from the short-time exposure pixel group, and the long exposure signal is generated.
• the time exposure signal and the short exposure signal are combined to generate a video signal for all pixels.
• This method also makes it possible to easily change the exposure time (long exposure period) of the pixels of the long time exposure pixel group by changing the first readout timing as described above. Further, by changing the second readout timing, it is possible to easily change the exposure time (short exposure period) of the pixels of the short exposure pixel group.
• the exposure time can be adjusted for each pixel group, and the dynamic range can be expanded according to the degree of difference in brightness of the subject. can do. For example, when photographing a subject with a large difference in brightness, the dynamic range can be expanded by adjusting the long exposure period to be short and the short exposure period to be short.
• all the pixels are divided into a long exposure pixel group and a short exposure pixel group, and accumulated charge signals having different exposure times within a predetermined frame period from pixels of each pixel group.
• the image capturing unit includes a first readout timing after a long exposure period elapses within a frame period, and a short time within a frame period.
• the second readout timing force S after the exposure period has passed can be adjusted independently, and the accumulated charge signal of the long exposure is read from the long exposure pixel group to the computer at the first readout timing.
• the procedure for reading the short-time exposure accumulated charge signal from the short-exposure pixel group at the second readout timing and the long-exposure pixel group Read from group A procedure for generating a long exposure signal using the accumulated charge signal for the long exposure and a procedure for generating a short exposure signal using the accumulated charge signal for the short exposure read from the short exposure pixel group. And a procedure for generating a video signal for all pixels by combining the long exposure signal and the short exposure signal.
• This program can also easily change the exposure time (long exposure period) of the pixels of the long exposure pixel group by changing the first readout timing as described above. Further, by changing the second readout timing, the exposure time (short exposure period) of the pixels of the short exposure pixel group can be easily changed. In this way, by adjusting the first readout timing and the second readout timing, the exposure time can be adjusted for each pixel group, and the dynamic range can be adjusted according to the degree of difference in brightness of the subject. Can be enlarged. For example, when photographing a subject with a large difference in brightness, the dynamic range can be expanded by adjusting the long exposure period to be short and the short exposure period to be short.
• all pixels are divided into two pixel groups, an image pickup unit capable of reading out accumulated charge signals having different exposure times from the pixels of each pixel group, and long exposure from a long exposure pixel group.
• the first readout timing for reading the accumulated charge signal and the short exposure pixel group force
• a readout timing adjustment unit that independently adjusts the second readout timing for reading the accumulated charge signal for short exposure.
• the exposure time can be adjusted for each gnole, and the dynamic range can be expanded according to the degree of difference in brightness of the subject.
• This imaging apparatus has a dynamic range expansion function, and this function is realized by a program stored in a memory or the like of the imaging apparatus.
• FIG. 1 is a block diagram showing the configuration of the imaging apparatus according to the present embodiment.
• FIG. 2 is a block diagram showing a configuration of the image sensor 1 of the present embodiment.
• FIG. 3 is an explanatory diagram showing the main configuration of the image sensor 1.
• the FIG. 4 is an explanatory diagram showing the pixel arrangement of the image sensor 1.
• the imaging apparatus includes an imaging element 1 such as a CCD or a CMOS, and a timing pulse generator 2 that controls the readout timing of the imaging element 1.
• the imaging device 1 corresponds to the imaging unit of the present invention
• the timing pulse generator 2 corresponds to the read timing adjustment unit of the present invention.
• the imaging apparatus includes a time axis converter 3 that performs the later-described synchronization processing on the two output signals (the long exposure signal and the short exposure signal) from the image sensor 1, and the time axis converter 3 Is combined with the output signal (simultaneous long exposure signal and short exposure signal) to generate a video signal for all pixels.
• the time axis converter 3 includes two line memories 5 for writing and reading the long exposure signal and the short exposure signal, respectively.
• the synthesis circuit 4 corresponds to the synthesis unit of the present invention.
• the imaging apparatus includes a gradation correction circuit 6 that performs gradation correction processing that enhances the contrast of the video signal, and luminance that separates the video signal into a luminance signal and a color difference signal and outputs the luminance signal and a color difference signal as a video output signal.
• Color difference signal generation circuit 7 is provided!
• the imaging device 1 includes a plurality of photodiodes 8 as light receiving elements.
• the number of pixels of the image sensor 1 is determined by the total number of the photodiodes 8.
• the photodiode 8 is arranged in a plane on the substrate 9 of the imaging device 1, and includes two groups of photodiodes 8 for long-time exposure and photodiode 8 for short-time exposure. It is divided into groups.
• the photodiode 8 for long exposure is indicated by “L”
• the photodiode 8 for short exposure is indicated by “S”.
• the pixel refers to a light receiving element constituting the image sensor 1 (CCD or the like).
• the photodiode 8 corresponds to the pixel of the present invention.
• the pixel group is a group of pixels.
• the group power of the long-time exposure photodiode 8 corresponds to the long-time exposure pixel group of the present invention, and the group of the photodiode 8 for short-time exposure.
• the force S corresponds to the short exposure pixel group of the present invention.
• a photodiode 8 for long-time exposure and a photodiode for short-time exposure. 8 are alternately arranged in the vertical and horizontal directions.
• the odd-numbered rows from the bottom are the rows of photodiodes 8 for long exposure
• the even-numbered rows from the bottom is a row of photodiodes 8 for short-time exposure.
• the odd-numbered columns from the left (1st row, 3rd IJth,...) are the rows of photodiodes 8 for long exposure, and the even-numbered rows from the left (2nd row, 4th row,...) Is a row of photodiodes 8 for short-time exposure.
• the long-time exposure photodiodes 8 in the odd-numbered rows from the bottom and the short-time exposure photodiodes 8 in the even-numbered rows from the bottom are shifted from each other.
• each photodiode 8 is arranged.
• the photodiodes 8 are arranged so that the long-time exposure photodiodes 8 in the odd-numbered columns from the left and the short-time exposure photodiodes 8 in the even-numbered columns from the left are shifted from each other. Has been.
• the pixel array is a Bayer array.
• Each photodiode 8 is arranged so that
• the G-component photodiodes 8 and B component photodiodes 8 are arranged alternately, and in the row of the long exposure photodiode 8 in the third row from the bottom, the R component photodiode 8 and the G component photodiode are arranged. 8 are arranged alternately.
• the long-time G component photodiode 8 is indicated by “LG”
• the long-time B component photodiode 8 is indicated by “LB”.
• the R component photodiode 8 for a long time is indicated by “LR”.
• the photo for the G component is used in the group of the short-time exposure photodiodes 8 in the even-numbered rows from the bottom.
• Diodes 8 and B component photodiodes 8 are arranged alternately, and in the fourth row of photodiodes 8 for short-time exposure from the bottom, the R component photodiode 8 and the G component photo diode are arranged. Diodes 8 are arranged alternately.
• the short-time G component photodiode 8 is indicated by “SG”
• the short-time B component photodiode 8 is indicated by “SB”.
• the short-time R component photodiode 8 is “SR”. It is shown.
• the photodiode 8 for the R component or the G component or the B component is a photodiode 8 having high sensitivity in the wavelength region of the R component (or G component or B component).
• photodiodes 8 having different sensitivities of the R component, the G component, and the B component may be used as the photodiodes 8 for the R component, the G component, and the B component, respectively.
• a color filter with high transmittance in the wavelength region of the R component, G component, and B component is provided on each photodiode 8 having the same sensitivity characteristics, and the photodiode 8 for R component, G component, and B component is provided. It may be used as
• the imaging device 1 has two vertical transfer paths that transfer charges accumulated in the photodiode 8 (accumulated charges) in the vertical direction (vertical direction, downward in FIG. 3).
• First vertical transfer path 10 and second vertical transfer path 11 and a horizontal transfer path 12 for transferring charges transferred from the vertical transfer path in the horizontal direction (horizontal direction, leftward in FIG. 3).
• the accumulated charge corresponds to the accumulated charge signal of the present invention.
• the first vertical transfer path 10 corresponds to the first transfer path of the present invention
• the second vertical transfer path 11 corresponds to the second transfer path of the present invention.
• the image pickup device 1 includes a first gate electrode 13 serving as a read path from the long-time exposure photodiode 8 to the first vertical transfer path 10 and a short-time exposure photodiode 8 from the second vertical transfer path.
• a second gate electrode 14 serving as a readout path to the transmission path 11 is provided.
• the first gate electrode 13 is controlled so as to read the accumulated charge from the long-time exposure photodiode 8 to the first vertical transfer path 10 when a gate voltage is applied from the timing pulse generator 2.
• the second gate electrode 14 is controlled so as to read the accumulated charge from the photodiode 8 for short time exposure to the second vertical transfer path 11 when the gate voltage is applied from the timing pulse generator 2. Yes.
• the first read timing for applying the gate voltage to the first gate electrode 13 and the second read timing for applying the gate voltage to the second gate electrode 14 can be adjusted independently.
• the first gate electrode 13 corresponds to the first gate electrode of the present invention
• the second gate electrode 14 corresponds to the second gate electrode of the present invention.
• the first gate electrode 13 and the first vertical transfer path 10 correspond to the first readout section of the present invention
• the second gate electrode 14 and the second vertical transfer path 11 correspond to the second readout section of the present invention.
• the first vertical transfer path 10 is provided at a position corresponding to the photodiode 8 for long-time exposure in the odd-numbered column from the left, and the short in the even-numbered column from the left.
• a second vertical transfer path 11 is provided at a position corresponding to the photodiode 8 for time exposure.
• the first gate electrode 13 connects the long-time exposure photodiode 8 and the first vertical transfer path 10
• the second gate electrode 14 connects the short-time exposure photodiode 8 and the second vertical transfer path. Road 11 is connected.
• Timing when the gate voltage is applied from the timing pulse generator 2 to the first gate electrode 13 (first readout timing), and timing when the gate voltage is applied from the timing pulse generator 2 to the second gate electrode 14 (first timing) (Read timing of 2) is controlled independently.
• the imaging device 1 can independently store the accumulated charges of different exposure times within one frame period (the accumulated charge of the photodiode 8 for long exposure and the accumulated charge of the photodiode 8 for short exposure). It is comprised so that it can read.
• the image sensor 1 generates a long-time exposure signal that generates a long-time exposure signal in accordance with the amount of accumulated charge read to the first vertical transfer path 10.
• a generation unit 15 and a short-time exposure signal generation unit 16 that generates a short-time exposure signal in accordance with the amount of accumulated charges read out to the second vertical transfer path 11 are provided.
• the long exposure signal generator 15 corresponds to the long exposure signal generator of the present invention
• the short exposure signal generator 16 corresponds to the short exposure signal generator of the present invention.
• FIG. 5 shows how the accumulated charge amount of the photodiode 8 changes with time.
• the substrate voltage is applied from the timing panel generator 2 at the start of one frame period, and the residual charges of all the photodiodes 8 (all pixels). Will be reset. Charge is accumulated in the photodiode 8 for a predetermined long exposure period. Therefore, it can be said that this is the start time of the long exposure period (the time when all the charges are reset at the start of one frame period).
• a gate voltage is applied from the timing pulse generator 2 to the first gate electrode 13, and the accumulated charge in the photodiode 8 for long exposure is read out. It is.
• This first readout timing can be said to be the end of the long exposure period. In the present embodiment, readout of the accumulated charge of the photodiode 8 for short-time exposure is not performed at the first readout timing.
• the substrate voltage is applied again from the timing pulse generator 2 to reset the residual charges of all the photodiodes 8 (all pixels). Charge is accumulated in the photodiode 8 for a predetermined short exposure period. Therefore, it can be said that the time point of resetting all charges in one frame period is the starting point of the short exposure period.
• a gate voltage is applied from the timing pulse generator 2 to the second gate electrode 14, and the accumulated charge in the photodiode 8 for short exposure is read out. It is.
• This second readout timing is the end point of one frame period and can be said to be the end point of the short exposure period. In the present embodiment, readout of the accumulated charge of the photodiode 8 for long exposure is not performed at the second readout timing.
• FIG. 6 shows a state in which the accumulated charge is read out from the photodiode 8 and a long-time exposure signal and a short-time exposure signal are output from the image sensor 1.
• the accumulated charge read from the long-time exposure photodiode 8 at the first read timing is read to the first vertical transfer path 10 via the first gate electrode 13 and 1 Holds on vertical transfer path 10.
• the accumulated charge read from the short-time exposure photodiode 8 at the second read timing is read to the second vertical transfer path 11 via the second gate electrode 14, and the second vertical transfer path. 11 is held on.
• the accumulated charges held in the first vertical transfer path 10 and the second vertical transfer path 11 are sequentially transferred in the vertical direction (downward in FIG. 6) and read out to the horizontal transfer path 12.
• the stored electrification read out to the horizontal transfer path 12 is sequentially transferred in the horizontal direction (leftward in FIG. 6) and output as a long-time exposure signal and a short-time exposure signal.
• the long-time exposure signal generation unit 15 generates a long-time exposure signal using the accumulated charge of the photodiode 8 for long-time exposure
• the short-time exposure signal generation unit 16 A short-time exposure signal is generated using the charge accumulated in the photodiode 8 for intermediate exposure.
• the generated long exposure signal and short exposure signal are output from the image sensor 1 as output signals and amplified by the amplifier 17.
• the output signal from the image sensor 1 is output in the order of the long exposure signal and the short exposure signal for each line (one row).
• FIG. 7 is an explanatory diagram showing how the time axis converter 3 performs a synchronization process on the long-time exposure signal and the short-time exposure signal read from the image sensor 1.
• the time axis converter 3 the time axis of the long exposure signal and the short exposure signal is doubled (1/2 speed) and the phases of the long exposure signal and the short exposure signal are matched.
• the synchronization process is done
• the long-time exposure signal and the short-time exposure signal read from the image sensor 1 for each line are written in the line memory 5 of the time-axis converter 3, respectively.
• the long exposure signal and the short exposure signal are written at the clock rate at the time of reading.
• the long exposure signal and the short exposure signal written in each line memory 5 are read out at a half clock rate.
• the long-time exposure signal and the short-time exposure signal are read at a timing at which the phases are aligned.
• the synthesizing circuit 4 synthesizes the synchronized long exposure signal and short exposure signal to generate a video signal for all pixels. After that, the tone correction circuit 6 performs tone correction processing that emphasizes the contrast of the video signal, and the luminance / chrominance signal generation circuit 7 separates the luminance signal and the chrominance signal and outputs them as a video output signal.
• the tone correction circuit 6 performs tone correction processing that emphasizes the contrast of the video signal
• the luminance / chrominance signal generation circuit 7 separates the luminance signal and the chrominance signal and outputs them as a video output signal.
• all the photodiodes 8 are divided into two groups (long exposure group and short exposure group).
• Image sensor 1 capable of reading out accumulated charges for different exposure times from photodiodes 8 of each group, and first readout timing for reading out accumulated charges for long exposure from photodiodes 8 for long exposure and for short exposure
• timing noise generator 2 that independently adjusts the second read-out timing for reading out the short-time exposure accumulated charge from the photodiode 8 of the photo diode 8, adjustment of the exposure time for each group of photodiodes 8 It is possible to expand the dynamic range according to the degree of difference in brightness of the subject.
• the exposure time (long exposure period) of the photodiode 8 for long exposure can be easily changed by changing the first readout timing. Further, by changing the second readout timing, the exposure time (short-time exposure period) of the short-time exposure photodiode 8 can be easily changed.
• the first readout timing and the second readout timing respectively, the exposure time can be adjusted for each group of photodiodes 8, and the exposure time can be adjusted according to the difference in brightness of the subject.
• the dynamic range can be expanded. For example, when shooting a subject with a large difference between light and dark, it is possible to increase the dynamic range by adjusting the long exposure period and shortening the short exposure period.
• the exposure time can be adjusted for each group of photodiodes 8.
• the photodiode 8 for long time exposure and the photodiode 8 for short time exposure are arranged without deviation in the vertical direction or the horizontal direction. Therefore, when all photodiodes 8 are divided into two groups (long exposure group and short exposure group), it is possible to suppress the occurrence of resolution bias in each group.
• the accumulated charges read from the photodiode 8 for long exposure and the photodiode 8 for short exposure are in a Bayer array, and thus generated from these accumulated charges.
• Long-time exposure signals and short-time exposure signals can be easily processed by general signal processing (signal processing for primary color layers).
• the imaging apparatus according to the present embodiment is different from the first embodiment in that the imaging element 1 includes a third gate electrode 18.
• the configuration and operation of the imaging apparatus of this embodiment are as follows. Unless otherwise specified, this is the same as in the first embodiment.
• FIG. 8 is a block diagram showing a configuration of the image sensor 1 of the present embodiment
• FIG. 9 is an explanatory diagram showing a main configuration of the image sensor 1.
• the image pickup device 1 includes a third gate electrode 18 serving as a read path from the short-time exposure photodiode 8 to the first vertical transfer path 10.
• the photodiode 8 for short time exposure and the first vertical transfer path 10 are connected by the third gate electrode 18.
• the third gate electrode 18 is controlled so as to read the accumulated charge from the short-time exposure photodiode 8 to the first vertical transfer path 10 when a gate voltage is applied from the timing pulse generator 2.
• the third gate electrode 18 corresponds to the third gate electrode of the present invention.
• the third gate electrode 18 and the first vertical transfer path 10 correspond to a third readout unit of the present invention.
• FIG. 10 shows how the accumulated charge amount of the photodiode 8 changes with time.
• the substrate voltage is applied from the timing pulse generator 2 at the start of one frame period as in the first embodiment. Residual charge of photodiode 8 (all pixels) is reset. Charge is accumulated in the photodiode 8 for a predetermined long exposure period.
• a gate voltage is applied from the timing pulse generator 2 to the first gate electrode 13 and the third gate electrode 18, and a photo for long exposure is applied.
• the accumulated charge for short-time exposure is read out by the diode 8.
• the substrate voltage is applied again from the timing pulse generator 2, and the residual charges of all the photodiodes 8 (all pixels) are reset. Charge is accumulated in the photodiode 8 for a predetermined short exposure period.
• a gate voltage is applied from the timing pulse generator 2 to the second gate electrode 14, and the accumulated charge in the photodiode 8 for short exposure is read out. It is. In the present embodiment, the stored charge of the photodiode 8 for long-time exposure is not read at the second read timing.
• FIG. 11 the accumulated charge is read out from the photodiode 8, and the image sensor 1 The manner in which the exposure signal and the short-time exposure signal are output is shown. As above,
• the accumulated charge read from the photodiode 8 for long-time exposure at the read timing of 1 is read to the first vertical transfer path 10 via the first gate electrode 13 and is transferred to the first vertical transfer path 10. Retained.
• the accumulated charge read from the short-time exposure photodiode 8 at the first read timing is also read out to the first vertical transfer path 10 via the third gate electrode 18. Are held on the first vertical transfer path 10.
• the long-exposure accumulated charge read from the short-time exposure photodiode 8 is added to the long-exposure accumulation charge read from the long-exposure photodiode 8. Is added.
• the accumulated charge read from the short-time exposure photodiode 8 at the second read timing is read to the second vertical transfer path 11 via the second gate electrode 14, and the second vertical transfer path 11 Held on.
• the accumulated charges held in the first vertical transfer path 10 and the second vertical transfer path 11 are sequentially transferred in the vertical direction (downward in FIG. 11) and read out to the horizontal transfer path 12.
• the stored electrification read out to the horizontal transfer path 12 is sequentially transferred in the horizontal direction (leftward in FIG. 11) and output as a long-time exposure signal and a short-time exposure signal.
• the long-time exposure signal generation unit 15 accumulates the long-time exposure accumulated from the long-time exposure photodiode 8 into the long-time exposure accumulated charge from the long-time exposure photodiode 8. The charge is added to generate a long exposure signal.
• the short-time exposure signal generation unit 16 generates a short-time exposure signal using the short-time exposure accumulated charge from the short-time exposure photodiode 8. The generated long exposure signal and short exposure signal are output from the imaging element 1 as output signals.
• the imaging apparatus according to the second embodiment of the present invention can also provide the same operational effects as those of the first embodiment.
• the long-time exposure accumulated charge read from the short-time exposure photodiode 8 that is not just the long-time exposure accumulated charge read from the long-time exposure photodiode 8 is used. It can be used, and the sensitivity of the long exposure signal is doubled.
• the gate voltage is applied to the third gate electrode 18 at the first read timing.
• the accumulated charge of the long exposure is read from the photodiode 8 for the short exposure to the first vertical transfer path 10.
• FIG. 1 An image pickup apparatus according to a third embodiment of the present invention will be described with reference to FIG.
• the configuration of the imaging apparatus of the present embodiment is the same as that of the second embodiment. Therefore, here, the operation of the imaging apparatus of the present embodiment will be described with reference to FIG.
• FIG. 12 shows how the accumulated charge amount of the photodiode 8 changes with time.
• the substrate voltage is applied from the timing pulse generator 2 at the start of one frame period, as in the second embodiment. Residual charge of photodiode 8 (all pixels) is reset. Charge is accumulated in the photodiode 8 for a predetermined long exposure period.
• the gate voltage is applied from the timing pulse generator 2 to the first gate electrode 13 and the third gate electrode 18, and the photo for long exposure is used.
• the accumulated charge for short-time exposure is read out by the diode 8.
• the substrate voltage is applied again from the timing pulse generator 2 to reset the residual charges of all the photodiodes 8 (all pixels). Charge is accumulated in the photodiode 8 for a predetermined short exposure period.
• a gate voltage is applied from the timing pulse generator 2 to the second gate electrode 14, and the accumulated charge of the short-time exposure photodiode 8 is read out. It is.
• the gate voltage is applied from the timing noise generator 2 to the first gate electrode 13 at the second read timing, and the accumulated charge in the photodiode 8 for long-time exposure is read out.
• the first gate electrode 13 and the first vertical transfer path 10 correspond to a fourth readout section of the present invention.
• the accumulated charge read from the long-time exposure photodiode 8 at the first read timing is read to the first vertical transfer path 10 via the first gate electrode 13. Are held on the first vertical transfer path 10.
• the data is read from the short-time exposure photodiode 8 at the first read timing.
• the accumulated charge is also read out to the first vertical transfer path 10 via the third gate electrode 18 and held on the first vertical transfer path 10.
• the accumulated charge of long exposure read from the photodiode 8 for short exposure is added to the accumulated charge of long exposure read from the photodiode 8 for long exposure. Is added.
• the accumulated charge read from the short-time exposure photodiode 8 at the second read timing is read to the second vertical transfer path 11 via the second gate electrode 14, and the second charge is read out. Holds on vertical transfer path 11.
• the accumulated charge force read from the photodiode 8 for long-time exposure at the second read timing is read to the first vertical transfer path 10 via the first gate electrode 13 and the first It is held on the vertical transfer path 10.
• the accumulated charge of the long exposure read from the photodiode 8 for long exposure and the accumulated charge of the long exposure read from the photodiode 8 for short exposure are The accumulated charge of the short-time exposure read out from the long-time exposure photodiode 8 is further added.
• the accumulated charges held in the first vertical transfer path 10 and the second vertical transfer path 11 are sequentially transferred in the vertical direction and read out to the horizontal transfer path 12.
• the stored electrification read to the horizontal transfer path 12 is sequentially transferred in the horizontal direction and output as a long exposure signal and a short exposure signal.
• the long-time exposure signal generation unit 15 accumulates the long-time exposure accumulated from the long-time exposure photodiode 8 into the long-time exposure accumulated charge from the long-time exposure photodiode 8. The charge is added, and the accumulated charge of short-time exposure from the long-time exposure photodiode 8 is added to generate a long-time exposure signal.
• the short-time exposure signal generation unit 16 generates a short-time exposure signal by using the short-time exposure accumulated charge from the short-time exposure photodiode 8. The generated long exposure signal and short exposure signal are output from the imaging element 1 as output signals.
• the imaging apparatus according to the third embodiment of the present invention can also provide the same operational effects as those of the second embodiment.
• the long-time exposure photodiode 8 and the long-time exposure photodiode 8 read out from the short-time exposure photodiode 8 alone are used.
• the accumulated charge of the short-time exposure read from the photodiode 8 can be used, and the sensitivity of the long-time exposure signal is further improved.
• each row power S of photodiode 8 is the same long time exposure photodiode 8 (or short exposure photodiode 8), or each row of photodiodes 8 is the same long time.
• An example in which the photodiode 8 for exposure (or the photodiode 8 for short-time exposure) is configured has been described.
• the scope of the present invention is not limited to these.
• a long-time exposure photodiode 8 and a short-time exposure photodiode are provided in each row or each column of the photodiode 8. 8 may be arranged alternately.
• the scope of the present invention is not limited to these. is not.
• the photodiodes 8 may be arranged so that the rows and columns of the photodiodes 8 are aligned.
• FIGS. 14A to 14D are explanatory diagrams of the pixel arrangement of the image sensor of the imaging device according to still another embodiment.
• the long-time exposure photodiodes 8 and the short-time exposure photodiodes 8 may be alternately arranged for each column (for example, for each column).
• the long-time exposure photodiodes 8 and the short-time exposure photodiodes 8 may be alternately arranged for each row (for example, for each row).
• the long-time exposure photodiode 8 and the short-time exposure The photodiodes 8 may be alternately arranged in the vertical direction and the horizontal direction one by one so as to form a checkered pattern.
• the long-exposure photodiode 8 and the short-exposure photodiode 8 form a pine pattern in 2 rows x 2 columns of blocks in the vertical and horizontal directions in units of blocks. They may be arranged alternately in the direction.
• the imaging apparatus can adjust the exposure time for each pixel group, and can expand the dynamic range according to the degree of difference in brightness of the subject. It is useful as an imaging device used for surveillance cameras.

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