JP2008236648A - Imaging apparatus and its driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain prevention of deterioration in image quality caused by temperature variations in a photographed image photographed by a simple constitution. <P>SOLUTION: In a timing adjusting circuit unit within an AFE in which a pseudo pixel signal which is a pseudo electric signal corresponding to an optical signal having a constant level to be incident into an imaging unit in an imaging element and having a constant level is made to be generated within the imaging element before outputting the imaging signal from the imaging element to an AFE having an A/D converter (step S216), then the pseudo pixel signal is to be output after being shaped (step S213), a timing of driving in the A/D converter is made to be adjusted based on the pseudo signal. Thereby time relative relation between an imaging signal to be output from the imaging element and sampling timing of the A/D converter becomes constant irrespective of environment temperature in the imaging apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus including an imaging unit that captures an incident optical signal as an electrical signal, and an A / D conversion unit that converts the electrical signal captured by the imaging unit into a digital signal, and a driving method thereof. It is.

  In an imaging apparatus using a solid-state imaging device such as a CCD or a CMOS sensor, the solid-state imaging device and the A / D converter are driven by a clock supplied from a drive signal generator. In general, an analog signal that is an output of the solid-state imaging device is sampled by an A / D converter and converted into a digital signal (for example, see Patent Document 1). A configuration example of a general imaging apparatus will be described with reference to FIG.

FIG. 7 is a block diagram illustrating a schematic configuration of a general imaging apparatus.
Reference numeral 101 in FIG. 7 denotes a (solid) image sensor, and for example, a CCD or a CMOS sensor is used. Reference numeral 102 denotes an A / D converter that converts an analog signal (Sig_OUT) that is an output of the image sensor 101 into a digital signal. Composed. Here, it is illustrated as “AFE”.

  Reference numeral 201 denotes a timing adjustment circuit unit configured by a DLL or the like provided in the AFE 102, and adjusts the timing of the AFE internal operation clock generated from the drive clock (AFE_CLK) supplied from the outside of the AFE 102. The image signal converted into a digital signal by the AFE 102 is sent to a subsequent processing block such as a DSP (Digital Signal Proseccer).

  A drive signal generator 104 generates a drive signal for controlling the driving of the image sensor 101 and the AFE 102. In FIG. 7, the drive clock (Sensor_CLK) of the image sensor 101 and the drive clock (AFE_CLK) of the AFE 102 are supplied to the image sensor 101 and the AFE 102, respectively.

  In the configuration shown in FIG. 7, the image sensor 101 is driven by Sensor_CLK supplied from the drive signal generator 104 to output Sig_OUT, which is sampled by the AFE 102. At this time, it is necessary to adjust the sampling timing of the AFE 102 in accordance with the delay amount determined by the wiring delay of Sensor_CLK, the circuit delay inside the image sensor 101, the wiring delay of Sig_OUT, and the like. Therefore, the delay adjustment time is absorbed by the setting by the timing adjustment circuit unit 201 to obtain a good image.

FIG. 8 is a timing chart showing the timing of each drive signal and the timing of the internal clock of the AFE by the drive signal generator of FIG.
A delay such as a wiring delay or a circuit delay occurs until Sensor_CLK is supplied from the drive signal generator 104 to the image sensor 101 to drive the image sensor 101 and a pixel signal (Sig_OUT) is input to the AFE 102. At this time, the AFE 102 absorbs this delay amount by the setting of the timing adjustment circuit unit 201 that generates the internal clock for performing the sampling operation from the AFE_CLK, and the A / D conversion sampling operation is performed in the stable period of the pixel signal. Adjust to. That is, the timing adjustment circuit unit 201 adjusts AFE_CLK based on a predetermined delay amount such as a wiring delay or a circuit delay to generate an internal clock.

JP 2003-229994 A

  However, the delay amount of the Sig_OUT signal shown in FIG. 8 is not constant under any conditions. For example, the delay amount also depends on the temperature due to a change in impedance due to a temperature change. In general, the delay amount decreases in a low temperature environment where the impedance decreases, so the phase of Sig_OUT changes relatively earlier. Conversely, in a high temperature environment, the delay increases because the impedance increases. , Sig_OUT changes in a further delay direction. For this reason, even if the phase relationship of each drive signal is appropriately adjusted under a normal environment (normal temperature), the phase relationship is broken under a high temperature or low temperature environment.

  Thus, even if the phase relationship of each drive signal is broken, there is no particular problem as long as the signal stabilization period shown in FIG. 8 is within the sampling range, but the phase relationship has changed beyond the signal stabilization period. In this case, naturally, the image quality of the captured image is deteriorated.

  In recent years, the signal stability period that can be sampled has also become shorter due to the demand for higher signal frequency due to the increase in the number of pixels and the reduction in noise level due to higher image quality. Is getting bigger.

  As a means for solving this problem, for example, a method of changing the setting by the timing adjustment circuit unit 201 depending on the temperature and setting the setting suitable for each temperature is conceivable. However, the above-described temperature variation of the delay amount varies from individual to individual, and it is very difficult to accurately detect the temperature of the substrate or the image sensor. Also, it is not practical to classify detailed temperature conditions and store settings suitable for each of them because the apparatus configuration and the processing content are complicated.

  That is, in the conventional image pickup apparatus, the delay amount cannot be adjusted with a simple configuration with respect to the delay amount due to the temperature change of the output signal of the image pickup element 101. As a result, it has been difficult to prevent image quality deterioration due to temperature changes in the captured image with a simple configuration.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an imaging apparatus that realizes prevention of image quality deterioration due to a temperature change of a captured image with a simple configuration, and a driving method thereof. And

  An image pickup apparatus according to the present invention includes an image pickup device including an image pickup section that picks up an incident optical signal as an electric signal, an A / D converter that converts the electric signal picked up by the image pickup section into a digital signal, and the image pickup element. Before the electrical signal is output from the image sensor to the A / D converter, a pseudo signal that is a pseudo electrical signal corresponding to a certain level of optical signal incident on the imaging unit is generated. Based on the pseudo signal shaped by the pseudo signal generating unit, the pseudo signal shaping unit shaping the pseudo signal generated by the pseudo signal generating unit, and the pseudo signal shaped by the pseudo signal shaping unit. A timing adjustment unit that adjusts the timing.

  An image pickup apparatus driving method according to the present invention includes an image pickup device including an image pickup unit that picks up an incident optical signal as an electric signal, and an A / D converter that converts the electric signal picked up by the image pickup unit into a digital signal. A pseudo electric signal corresponding to a constant level optical signal incident on the imaging unit before outputting the electric signal from the imaging element to the A / D converter. A pseudo signal generation step for generating a pseudo signal in the image sensor, a pseudo signal shaping step for shaping the pseudo signal generated in the pseudo signal generation step, and a pseudo signal shaped in the pseudo signal shaping step And a timing adjustment step of adjusting the drive timing in the A / D converter.

  According to the present invention, the temporal relative relationship between the electrical signal output from the imaging device and the sampling timing of the A / D converter can be made constant regardless of the environmental temperature in the imaging device. Thereby, it is possible to prevent the deterioration of the image quality due to the temperature change of the captured image with a simple configuration.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus 100 according to an embodiment of the present invention. Here, in each structure of FIG. 1, the same code | symbol is attached | subjected about the structure similar to FIG.

  Reference numeral 101 in FIG. 1 denotes a (solid) image sensor, and in the present embodiment, for example, a CCD or a CMOS sensor is used. Reference numeral 102 denotes an analog front end (AFE). The AFE 102 has a function of performing analog-digital conversion, OB clamping, a gain variable amplifier, and the like on an electrical signal (imaging signal) from the imaging element 101. Here, the OB clamping process is a process of performing offset adjustment on the signal so that the output of the light-shielding part (optical black part: OB part) of the image sensor 101 becomes a predetermined value.

  Reference numeral 103 denotes a DSP (Digital Signal Processor) that performs various correction processes and development processes on data (digital signals) from the AFE 102. Further, the DSP 103 performs control of various memories such as the ROM 106 and the RAM 107 and processing for writing image data to the recording medium 108.

  A drive signal generator 104 supplies drive signals such as clock signals and control signals to the image sensor 101, AFE 102, and DSP 103, and is controlled by the CPU 105.

  Reference numeral 105 denotes a CPU that controls the DSP 103 and the drive signal generator 104, and controls camera functions by various units (photometry control unit and distance measurement control unit) (not shown) that perform photometry and distance measurement. The CPU 105 is connected to each of the switches 109 to 111 and the mode dial 112, and executes processing corresponding to each state.

  Reference numeral 106 denotes a ROM that stores a control program for the imaging apparatus 100 that is processed by the CPU 105 and various correction data. Reference numeral 107 denotes a RAM that temporarily stores image data and correction data processed by the DSP 103. Here, the RAM 107 can be accessed at a higher speed than the ROM 106.

  Reference numeral 108 denotes a recording medium such as a compact flash (registered trademark) card that stores image data of a photographed image, and is connected to the imaging apparatus 100 via a connector (not shown).

  Reference numeral 109 denotes a power switch for starting up the imaging apparatus 100. Reference numeral 110 denotes a first shutter switch SW1 that instructs the start of operations such as photometry processing and distance measurement processing. Reference numeral 111 denotes a second shutter switch SW2 that drives a mirror and a shutter (not shown) and instructs the start of a series of imaging operations to write a signal read from the imaging element 101 to the recording medium 108 via the AFE 102 and the DSP 103.

Next, an operation procedure of the imaging apparatus 100 illustrated in FIG. 1 will be described.
FIG. 2 is a flowchart illustrating a driving method of the imaging apparatus 100 according to the embodiment of the present invention.

  First, in step S <b> 101, the CPU 105 determines whether or not a power switch (power SW) 109 that activates the imaging apparatus 100 is turned on. If the result of this determination is that the power switch 109 is OFF, processing waits in step S101 until it is determined that the power switch 109 is ON. On the other hand, if the result of determination in step S101 is that the power switch 109 is ON, processing proceeds to step S102.

  In step S102, the CPU 105 determines whether or not the mode dial 112 is set to the shooting mode. If the result of this determination is that a mode other than the shooting mode has been set, processing proceeds to step S103, processing according to the selected mode is performed, and processing returns to step S101. On the other hand, if the result of determination in step S102 is that shooting mode has been set, processing proceeds to step S104.

  In step S104, the CPU 105 determines whether or not the first shutter switch (SW1) 110 is ON. If the result of this determination is that the first shutter switch (SW1) 110 is OFF, the process waits in step S104 until it is determined that the first shutter switch (SW1) 110 is ON. On the other hand, if the result of determination in step S104 is that the first shutter switch (SW1) 110 is on, the process proceeds to step S105.

  In step S105, the CPU 105 uses a photometry control unit and a distance measurement control unit (not shown) to perform photometry processing for determining the aperture value and the shutter speed, and the focus of the photographing lens (not shown) to the subject (not shown). Ranging is performed.

  When the photometry / ranging process in step S105 is completed, in step S106, the CPU 105 determines whether or not the second shutter switch (SW2) 111 is ON. If the result of this determination is that the second shutter switch (SW2) 111 is OFF, the process waits in step S106 until it is determined that the second shutter switch (SW2) 111 is ON. On the other hand, if the result of determination in step S106 is that the second shutter switch (SW2) 111 is on, the process proceeds to step S107.

  In step S107, the CPU 105 executes a shooting process. Details of this photographing process will be described later with reference to FIG.

  When the photographing process in step S107 is completed, subsequently, in step S108, the CPU 105 causes the DSP 103 to develop the photographed image data.

  Subsequently, in step S109, the CPU 105 causes the DSP 103 to perform compression processing on the image data for which development processing has been completed, and stores the compressed image data in an empty area of the RAM 107.

  Subsequently, in step S <b> 110, the CPU 105 causes the DSP 103 to read out the image data stored in the RAM 107 and record it on the recording medium 108. After the end of this recording process, the CPU 105 shifts the operation state of the imaging apparatus 100 to step S101 to prepare for the next shooting.

Next, details of the photographing process in step S107 will be described.
FIG. 3 is a flowchart showing detailed processing in the photographing processing in step S107 of FIG.

  First, in step S201, a mirror (not shown) is moved to the mirror up position.

  Subsequently, in step S202, the aperture (not shown) is driven to a predetermined aperture value based on the photometric data obtained by the photometric processing in step S105.

  Subsequently, in step S203, a clear process of the charge (imaging signal) accumulated in the imaging element 101 is performed.

  Subsequently, in step S <b> 204, accumulation of electric charges (imaging signals) for the image sensor 101 is started.

  After the start of charge accumulation in step S204, subsequently, in step S205, a shutter (not shown) is opened, and exposure of the image sensor 101 is started (step S206). By this step S206, the image sensor 101 accumulates charges (imaging signals) corresponding to the light signal of the incident subject.

  After the exposure is started in step S206, in step S207, it is determined whether or not to end the exposure according to the photometric data. As a result of this determination, if the exposure is not terminated, the process waits in step S207 until it is determined that the exposure is terminated. On the other hand, if the result of determination in step S207 is that exposure is to end, processing proceeds to step S208.

  In step S208, the shutter (not shown) is closed.

  Subsequently, in step S209, the diaphragm (not shown) is driven to the full aperture value.

  Subsequently, in step S210, the mirror (not shown) is driven to the mirror down position.

  Subsequently, in step S211, it is determined whether or not the set charge accumulation time has elapsed. If it is determined that the set charge accumulation time has not elapsed, the process waits in step S211 until it is determined that the set charge accumulation time has elapsed. On the other hand, if the set charge accumulation time has elapsed as a result of the determination in step S211, the process proceeds to step S212.

  In step S212, charge accumulation in the image sensor 101 is terminated.

  Subsequently, in step S213, output of the pseudo pixel signal from the image sensor 101 is started.

  Subsequently, in step S214, the setting of the timing adjustment circuit unit (timing adjustment unit) 201 is determined so that the AFE 102 that has received the pseudo pixel signal from the image sensor 101 can sample the signal stabilization period. That is, in step S214, the phase of the internal clock in the AFE 102 is adjusted so that the signal stabilization period can be sampled with respect to AFE_CLK from the drive signal generator (drive signal generator) 104.

  Subsequently, in step S215, the output of the pseudo pixel signal from the image sensor 101 is terminated.

  Subsequently, in step S216, the imaging signal in the imaging element 101 is read. That is, processing for outputting an image signal captured by the image sensor 101 to the AFE 102 is performed. Thereafter, a series of processes in the photographing process is ended, and the process proceeds to step S108 in FIG. In the readout of the imaging signal in step S216, since the timing adjustment circuit unit 201 has already set an appropriate timing so that the signal stabilization period can be sampled in the AFE 102, a good image is always obtained regardless of the temperature environment or the like. be able to.

  Here, using FIG. 4 and FIG. 5, the operation of the image sensor 101 in reading the image signal in step S <b> 216 will be described.

FIG. 4 is a block diagram showing a schematic configuration inside the image sensor 101.
The imaging element 101 includes an imaging unit 10, a vertical scanning circuit unit 20, and a readout circuit unit 30.

  The imaging unit 10 includes pixels 11 arranged in a two-dimensional matrix. The imaging unit 10 converts the incident optical signal of the subject into an electrical signal (imaging signal). That is, the imaging unit 10 performs imaging using the incident optical signal of the subject as an electrical signal (imaging signal). In reading out the imaging signal of each pixel 11, first, the drive line V <b> 1 for driving the pixels 11 in the first row arranged in a two-dimensional matrix is selected by the operation of the vertical scanning circuit unit 20.

  When a drive signal is supplied from the vertical scanning circuit unit 20 to the selected drive line V1, an image pickup signal based on an optical signal accumulated in each pixel 11 in the first row connected to the drive line V1 is output vertically. The data is transferred to the line memory 31 connected to each vertical output line via the lines H1 to H5.

  Thereafter, by sequentially driving the readout switch 33 by the operation of the horizontal scanning circuit section 32, the signal stored in the line memory 31 is read out to the common output line 34, amplified in the amplification circuit section 35, and output from the output terminal Sig_OUT. Is done. Here, the comparator 36 is for shaping the pseudo pixel signal and outputting it as a clock from the output terminal CLK_OUT.

  Subsequently, the drive line V2 for driving the pixels 11 in the second row is selected again by the operation of the vertical scanning circuit unit 20, and the same operation as that for the first row is repeated.

  FIG. 5 is a circuit diagram showing a detailed configuration of the readout circuit unit 30 that reads a signal from a selected pixel 11. Specifically, FIG. 5 shows a detailed configuration of the readout circuit unit 30 corresponding to the line memory 31, the horizontal scanning circuit unit 32, the readout switch 33, the common output line 34, the amplification circuit unit 35, and the comparator 36 in FIG. 4. It is a thing.

  In FIG. 5, Q <b> 1 and Q <b> 2 are switches that transfer an output signal from the pixel 11 to memories Cts and Ctn corresponding to the line memory 31, respectively. Q3 and Q4 are switches for reading from the memories Cts and Ctn to the common output line 34, respectively.

  Chs and Chn are read capacitors, and are generally formed by parasitic capacitors such as a wiring capacitor attached to the common output line 34. Q5 and Q6 are reset switches for the read capacitors Chs and Chn.

  Q7 and Q8 are switches for charging dummy signals (pseudo pixel signals) to the memories Cts and Ctn from the power sources Vdmys and Vdmyn, respectively, in order to output (generate) pseudo pixel signals in the present embodiment. The switches Q7 and Q8 and the power sources Vdmys and Vdmyn constitute a “pseudo signal generation unit” provided in the image sensor. The pseudo signal generator generates pseudo pixel signals (Vdmys, Vdmyn), which are pseudo electrical signals corresponding to optical signals of a certain level incident on the imaging unit 10, in the image sensor 101.

  Q9 is a switch for inputting the pseudo pixel signal to the comparator 36 for shaping the pseudo pixel signal. As described above, the comparator 36 shapes the pseudo pixel signal and outputs it as a clock from the output terminal CLK_OUT. The operation during the output period of the pseudo pixel signal will be described later.

  In reading out the imaging signal in the pixel 11, first, the output pulse Ptn is turned on in order to write the reset noise signal in the memory Ctn. Next, the output pulse Pts is turned on in order to write the imaging signal component based on the optical signal accumulated in the pixel 11 to the memory Cts.

  Thereafter, the signals stored in the memories Cts and Ctn are read out to the reading capacitors Chs and Chn of the common output line 34 by simultaneously turning on the switches Q3 and Q4 by the output pulse Ph of the horizontal scanning circuit section 32, respectively. The signal read out in this way is subtracted in the amplification circuit unit 35, and reset noise is removed, and a good imaging signal is output from the output terminal Sig_OUT to the AFE 102. Finally, the common output line 34 is reset by turning on the switches Q5 and Q6 by the reset pulse Pchres to prepare for the output of the imaging signal from the next pixel 11.

  On the other hand, in the pseudo pixel signal output period in steps S213 to S215, the switches Q1 and Q2 are not turned on, but instead the switches Q7 and Q8 are turned on by the Pdmy signal. Thereby, the pseudo pixel signals (Vdmys, Vdmyn) can be written in the memories Cts and Ctn, respectively.

  By operating the horizontal scanning circuit unit 32 in this state, a pseudo pixel signal corresponding to Vdmys−Vdmyn is output from the amplification circuit unit 35 to the AFE 102 via the output terminal Sig_OUT. At the same time, since the switch Q9 is turned on by the Pdmy signal, the pseudo pixel signal output from the amplifier circuit unit 35 is waveform-shaped by the comparator 36 and output from the output terminal CLK_OUT to the AFE 102.

FIG. 6 is a timing chart showing the timing relationship of each signal in the pseudo pixel signal output period in the imaging apparatus 100 according to the embodiment of the present invention.
The horizontal scanning circuit unit 32 is driven based on Sensor_CLK input from the drive signal generator 104 to the image sensor 101, and a pseudo pixel signal is output from the output terminal Sig_OUT to the AFE 102. When the temperature changes, the phase of the signal output from the output terminal Sig_OUT changes due to the temperature characteristics of the image sensor 101. At the same time, a pseudo pixel signal obtained by shaping the pseudo pixel signal output from the output terminal Sig_OUT by the comparator 36 is also output from the output terminal CLK_OUT. The phase of this signal is also the same amount as the temperature change of the output signal of the output terminal Sig_OUT. Change.

  In FIG. 6, the timings of the Sig_OUT signal and the CLK_OUT signal at the reference temperature t1 are indicated by dotted lines, and the phase difference between the AFE_CLK (operation clock of the AFE 102) signal and the CLK_OUT signal at this time is τ1. The phase of the AFE internal clock signal that is optimal for the AFE 102 to sample the Sig_OUT signal is indicated by a dotted line, and the setting in the timing adjustment circuit unit 201 at this time is α.

Next, consider a case where the temperature changes to t2.
The timings of the Sig_OUT signal and the CLK_OUT signal at the temperature t2 are indicated by solid lines. In step S214 described above, the AFE 102 detects the phase difference τ2 between the AFE_CLK signal and the CLK_OUT signal at this time, and sets the phase timing adjustment by the timing adjustment circuit unit 201 to β = α + τ2-τ1.

  By the timing adjustment by the timing adjustment circuit unit 201, the phase of the generated AFE internal clock changes following the phase of the CLK_OUT signal. That is, since it changes following the signal of Sig_OUT, the sampling operation of the AFE 102 is always performed on the same position of the signal of Sig_OUT.

  According to the imaging apparatus 100 of the present embodiment, before the pseudo signal generator provided in the imaging device 101 outputs an imaging signal from the imaging device 101 to the AFE (A / D converter) 102 (step S216). Then, a pseudo pixel signal corresponding to an optical signal of a certain level incident on the imaging unit 10 is generated, the waveform is shaped by the comparator (pseudo signal shaping unit) 36, and the timing adjustment circuit is based on the waveform shaped pseudo pixel signal. Since the timing of driving in the AFE (A / D converter) 102 is adjusted by the unit 201, the temporal relative relationship between the imaging signal output from the imaging device 101 and the sampling timing of A / D conversion in the AFE 102 Can be made constant regardless of the environmental temperature in the imaging apparatus 100. Thereby, it is possible to prevent deterioration in image quality due to a temperature change of a captured image with a simple configuration in which a pseudo signal generation unit and a pseudo signal shaping unit are simply provided in the image sensor 101.

  In the present embodiment, the timing adjustment circuit unit 201 is provided inside the AFE 102, and the temperature change of the phase in the detected output signal from the image sensor 101 is fed back to the setting of the timing adjustment circuit unit 201, whereby the image sensor 101, the relationship between the output signal from the sampling timing and the sampling timing is kept constant. For example, the timing adjustment circuit unit 201 is provided in the drive signal generator 104 that supplies the AFE operation clock (AFE_CLK). It may be configured to adjust the phase of the AFE operation clock. Further, a configuration may be employed in which means for supplying the AFE operation clock from the image sensor 101 and a timing adjustment circuit unit for adjusting the timing are provided, and the temperature change of the pseudo pixel signal is fed back to the timing adjustment circuit unit. .

  1, 4, and 5 constituting the imaging apparatus according to the present embodiment described above, and each step of FIGS. 2 and 3 showing the driving method of the imaging apparatus is performed on the RAM or ROM of the computer. This can be realized by operating the stored program. This program and a computer-readable storage medium storing the program are included in the present invention.

  Specifically, the program is recorded in a storage medium such as a CD-ROM, or provided to a computer via various transmission media. As a storage medium for recording the program, a flexible disk, a hard disk, a magnetic tape, a magneto-optical disk, a nonvolatile memory card, and the like can be used in addition to the CD-ROM. On the other hand, as the transmission medium of the program, a communication medium in a computer network (LAN, WAN such as the Internet, wireless communication network, etc.) system for propagating and supplying program information as a carrier wave can be used. Moreover, examples of the communication medium at this time include a wired line such as an optical fiber, a wireless line, and the like.

  In addition, the function of the imaging apparatus according to the present embodiment is realized by executing a program supplied by the computer, and an OS (operating system) or other application software in which the program is operating in the computer. When the functions of the imaging apparatus according to the present embodiment are realized in cooperation with the present embodiment, or all or part of the processing of the supplied program is performed by a function expansion board or a function expansion unit of the computer. Such a program is also included in the present invention when the function of the imaging apparatus is realized.

1 is a block diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment of the present invention. 3 is a flowchart illustrating a method for driving the imaging apparatus according to the embodiment of the present invention. It is a flowchart which shows the detailed process in the imaging | photography process of step S107 of FIG. It is a block diagram which shows schematic structure inside an image pick-up element. It is a circuit diagram which shows the detailed structure of the read-out circuit part which reads the signal from a certain selected pixel. 5 is a timing chart showing the timing relationship of each signal in the output period of the pseudo pixel signal in the imaging apparatus according to the embodiment of the present invention. 1 is a block diagram illustrating a schematic configuration of a general imaging apparatus. 8 is a timing chart showing the timing of each drive signal and the timing of the internal clock of the AFE by the drive signal generator of FIG.

Explanation of symbols

101: Image sensor 102: AFE
103: DSP
104: Drive signal generator 105: CPU
106: ROM
107: RAM
108: Recording medium 109: Power switch 110: First shutter switch (SW1)
111: Second shutter switch (SW2)
112: mode dial 201: timing adjustment circuit unit 10: imaging unit 11: pixel 20: vertical scanning circuit unit 30: readout circuit unit 31: line memory 32: horizontal scanning circuit unit 33: readout switch 34: common output line 35: amplification Circuit part 36: Comparator

Claims (5)

An imaging device including an imaging unit that images an incident optical signal as an electrical signal;
An A / D converter that converts an electrical signal imaged by the imaging unit into a digital signal;
A pseudo electric signal that is provided in the imaging device and is equivalent to an optical signal of a certain level that is incident on the imaging unit before the electrical signal is output from the imaging device to the A / D converter. A pseudo signal generator for generating a signal;
A pseudo signal shaping unit that shapes the pseudo signal generated by the pseudo signal generation unit;
An imaging apparatus comprising: a timing adjustment unit that adjusts a driving timing in the A / D converter based on the pseudo signal shaped by the pseudo signal shaping unit. A drive signal generator for generating a drive signal for driving the A / D converter;
The timing adjusting unit adjusts a driving timing in the A / D converter according to a phase difference between the driving signal generated by the driving signal generating unit and the pseudo signal shaped by the pseudo signal shaping unit. The imaging apparatus according to claim 1.   The imaging apparatus according to claim 2, wherein the timing adjustment unit adjusts a driving timing in the A / D converter by adjusting a phase of the driving signal generated by the driving signal generation unit. .   The imaging apparatus according to claim 1, wherein the pseudo signal shaping unit is formed in the imaging element. A driving method for an imaging apparatus, comprising: an imaging element including an imaging unit that images an incident optical signal as an electrical signal; and an A / D converter that converts the electrical signal captured by the imaging unit into a digital signal. ,
Before outputting the electrical signal from the imaging device to the A / D converter, a pseudo signal that is a pseudo electrical signal corresponding to a certain level of optical signal incident on the imaging unit is generated in the imaging device. Pseudo signal generation step
A pseudo signal shaping step for shaping the pseudo signal generated in the pseudo signal generating step;
And a timing adjustment step of adjusting a drive timing in the A / D converter based on the pseudo signal shaped in the pseudo signal shaping step.

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