JPH0818871A - Image pickup device - Google Patents

Abstract

PURPOSE:To provide an image pickup device from which a stable output is obtained independently of temperature. CONSTITUTION:A CCD(charge coupled device) 1 reads a charge in response to a light from an object and receives a reset voltage from an RD pulse generator 9 and a reference signal based on a reset signal from an RG pulse generating section 8 and provides an output of a read signal. A CDS (correlation double sampling circuit) 2 eliminates noise superimposed on the read signal. A gain control amplifier 3 adjusts a level of the read signal with a feedback signal. A video amplifier 5 amplifies the read signal to provide an output of an image pickup signal. A detection section 6 extracts the reference signal from the image pickup signal and an error amplifier section 7 detects a change in the reference signal to provide an output of the feedback signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for picking up light from a subject and outputting an image pickup signal, and more particularly to a temperature-compensated device provided with a charge-coupled device for converting light from the subject into electric charges and outputting the electric charges. The present invention relates to an image pickup apparatus that holds the level of an output image pickup signal constant by performing the above.

[0002]

2. Description of the Related Art Conventionally, a charge-coupled device (hereinafter referred to as CCD) has been used as an image pickup device in an image pickup device which converts image pickup light from a subject into electric charges and outputs an image pickup signal. This CCD is capable of manufacturing a CCD having an increased number of pixels due to a dramatic improvement in semiconductor manufacturing technology in recent years. For example, high definition television (HDT
V) A CCD used in a television camera device for the device has a degree of image disparity of about 2 million.

Due to such a decrease in the area of the pixel due to the increase in the number of pixels of the CCD, the amount of accumulated charge per pixel is reduced, the intensity of the image pickup signal taken out becomes small, and the intensity of the image pickup signal due to the temperature change. The effect of is not negligible.

Therefore, a CCD read circuit is used which compensates for the change in the intensity of the image pickup signal from the CCD due to the temperature change. This readout circuit is, for example, CC
A reference pulse is inserted into the image pickup signal from D, and the overall gain is adjusted according to the change in the level of this pulse to perform temperature compensation.

This reading circuit is specifically shown in FIG.
As shown in FIG. 5, a correlated double sampling circuit (hereinafter referred to as CDS) 51 that removes a DC voltage due to reset noise or the like included in the image pickup signal read from the CCD 50.
And the reference pulse supplied from the supply terminal 52 to the CDS5
Adder 53 to be inserted into the image pickup signal from 1, and adder 5
A video amplifier 55 that amplifies the image pickup signal from 3 and outputs the amplified image pickup signal to the output terminal 54.

Then, the CDS 51 performs so-called correlated double sampling on the image pickup signal read from the CCD 50, removes a DC voltage due to reset noise or the like contained in the image pickup signal from the CCD 50, and supplies it to the adding section 53. To do.

The adder 53 inserts the reference pulse supplied from the supply terminal 52 into the image pickup signal from the CDS 51 and supplies it to the video amplifier 55.

The video amplifier 55 amplifies the image pickup signal from the adder 53 and outputs it to the output terminal 54, detects the level of the reference pulse in the image pickup signal, and adjusts the gain according to the detected output. As a result, the output level of the image pickup signal to be output is kept constant.

[0009]

However, in this read circuit, since the reference pulse is inserted in the output of the CDS 51, the temperature characteristic of the video amplifier 54 can be compensated, but the temperature compensation of the CCD 51 and the CDS 52 is not performed. There was a problem I could not do.

Therefore, in order to solve this problem, a CCD
It is conceivable that an adder is provided after 50 to insert a reference pulse into the output of the CCD 50. In this case, the CCD
In order to prevent the read signal from 50 from deteriorating, an adder with good frequency characteristics is required, and there are restrictions on the circuit configuration or costs, which makes it difficult to realize.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image pickup apparatus which can obtain a stable output regardless of temperature.

[0012]

An image pickup apparatus according to the present invention reads a reference signal generating means for generating a reference signal and a charge corresponding to light from a subject, and inserts the reference signal from the reference signal generating means. And an image sensor that outputs a read signal,
Based on the processing means for performing a predetermined process on the read signal from the image pickup device to output the image pickup signal, the detecting means for detecting a change in the level of the output corresponding to the reference signal of the processing means, and the detection output of the detecting means. Adjusting means for adjusting the level of the output of the processing means.

Further, the image pickup apparatus according to the present invention is characterized in that the processing means comprises an amplifying means for amplifying a read signal from the image pickup element.

The image pickup apparatus according to the present invention is characterized by including a gain control amplifier for adjusting the level of the read signal supplied to the processing means by the adjusting means.

The image pickup apparatus according to the present invention is characterized in that the image pickup element is a solid-state image pickup element.

Further, the image pickup apparatus according to the present invention is characterized in that the processing means includes a removing means for removing the DC component superimposed on the read signal from the solid-state image pickup element.

Further, the image pickup apparatus according to the present invention is characterized in that the removing means comprises sampling means for performing correlated double sampling on the read signal from the solid-state image pickup device.

In the image pickup device according to the present invention, the solid-state image pickup element holds the charge from the read control means for reading out the charge corresponding to the light from the object and the read control means, and outputs the held charge as a read signal. Holding means and a gate means for resetting the holding means by switching the reset voltage based on the gate voltage and supplying the reset voltage to the holding means. Is controlled to control the switching timing of the gate means to generate a reference signal and insert it into the read signal.

Further, in the image pickup device according to the present invention, the solid-state image pickup device holds the charge from the read control means for reading the charge according to the light from the object and the read control means.
The holding means outputs the held charge as a read signal, and the gate means resets the holding means by switching the reset voltage based on the gate voltage and supplying the reset voltage to the holding means. It is characterized in that the reference signal is generated and inserted into the read signal by varying the voltage and controlling the switching timing of the gate means.

[0020]

In the image pickup apparatus according to the present invention, the image pickup device reads out the electric charge according to the light from the subject, inserts the reference signal from the reference signal generating means and outputs the read signal, and the processing means outputs the read signal. The read signal is subjected to predetermined processing to output an image pickup signal.

The detecting means detects a change in the output level corresponding to the reference signal of the processing means, and the adjusting means adjusts the output level of the processing means based on the detection output of the detecting means.

When the temperature changes and the output level of the processing means corresponding to the reference signal changes, the detecting means
The change in the output level of the processing means is detected, and the adjusting means adjusts the output level of the processing means based on the detection output of the detecting means. As a result, even if the temperature changes, the output level of the processing means becomes constant.

Further, in the image pickup apparatus according to the present invention, the reference signal generating means changes the reset voltage and controls the gate voltage to control the switching timing of the gate means of the solid-state image pickup device, thereby making the reference signal. Is generated and inserted into the read signal.

Further, in the image pickup apparatus according to the present invention, the reference signal generating means generates the reference signal by controlling the switching timing of the gate means of the solid-state image pickup device while varying the gate voltage. To insert.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of an image pickup apparatus according to the present invention will be described in detail below with reference to the drawings.

In this embodiment, the present invention is applied to an image pickup device using a charge coupled device as an image pickup device.

For example, as shown in FIG. 1, this image pickup device reads a charge according to light from a subject, inserts a reference signal (hereinafter referred to as a reference pulse), and outputs a read signal (hereinafter referred to as a charge coupled device). , CCD) 1 and CCD
Correlated double sampling circuit 2 (hereinafter, referred to as CDS) for removing noise such as DC component superimposed on the read signal from
, And a gain control amplifier 3 for adjusting the level of the read signal from the CDS 2, and a video amplifier 5 for amplifying the read signal from the gain control amplifier 3 and outputting an image pickup signal from the output terminal 4. .

Further, as shown in FIG. 1 described above, the image pickup device further includes a detector 6 for extracting an output (hereinafter referred to as a reference voltage) corresponding to a reference pulse from the image pickup signal from the video amplifier 5, and a detector. The reference voltage from the unit 6 is compared with the reference voltage to obtain an error, and the error amplifying unit 7 is supplied as a feedback signal to the gain control amplifier 3.

Further, as shown in FIG. 1 described above, this image pickup apparatus generates a reset signal and supplies it to the CCD 1.
The G pulse generator 8 and the CCD 1 for generating a reset voltage
And an RD pulse generator 9 for supplying the
On the basis of the reset signal from the RG pulse generator 8, the reset voltage from the RD pulse generator 9 is switched to generate a reference pulse, which is inserted into the read signal.

Then, the CCD 1 reads the electric charge according to the light from the subject, inserts the reference pulse as described above to form a read signal, and supplies the formed read signal to the CDS 2. The CDS 2 performs so-called correlated double sampling on the read signal from the CCD 1 to remove noise such as a DC component superimposed on the read signal and supplies it to the gain control amplifier 3.

The gain control amplifier 3 adjusts the level of the read signal from the CDS 2 on the basis of the feedback signal from the error amplification section 7 and supplies it to the video amplifier 5. The video amplifier 5 amplifies the read signal supplied from the gain control amplifier 3 and outputs an imaging signal as an output terminal 4
And to the detection unit 6.

The detection section 6 extracts a reference voltage from the image pickup signal supplied from the video amplifier 5 and supplies it to the error amplification section 7. The error amplification unit 7 compares the reference voltage from the detection unit 6 with a reference voltage supplied from the outside, obtains an error, and supplies it as a feedback signal to the gain control amplifier 3.

Specifically, the output section for outputting the read signal of the CCD 1 is, for example, as shown in FIG. 2, a reset terminal to which a reset signal (reset gate pulse) RG from the RG pulse generating section 8 is supplied. 10, a terminal 11 to which the reset voltage RD from the RD pulse generator 9 is supplied, a reset gate 12 for switching the reset voltage RD by a reset gate pulse RG from the reset terminal 10, and a transfer register of the CCD 1 ( A read terminal 13 to which a charge is supplied from an unillustrated), an amplifier 14 that holds the charge from the read terminal 13 and outputs the held charge as a read signal, and a read signal from the amplifier 14. An output amplifier 15 for amplifying and outputting is provided.

The amplifying section 14 is composed of a so-called floating diffusion amplifier, which is composed of a capacitor whose one end is in an electrically floating state. The amplifying section 14 holds and holds electric charges supplied from the read terminal 13. The charge is supplied to the output amplifier 15 as a read signal. Further, the amplification section 14 is configured to reset the charges held by the reset voltage RD supplied via the reset gate 12.

The cycle of the reset gate pulse RG supplied to the reset terminal 10 is the time for reading the charge of one pixel of the CCD 1 as shown in FIG. 3A, for example. When the reset gate pulse RG becomes high level,
The amplification unit 14 becomes the potential of the reset voltage RD supplied to the terminal 11. That is, the amplification unit 14 is reset every time the charge of one pixel is read.

In the CCD 1, the reference pulse is generated by the reset gate pulse RG from the RG pulse generator 8 and the reset voltage RD from the RD pulse generator 9 as described above.

Specifically, when generating the reference pulse, the RG pulse generator 8 sets the reset gate pulse RG to VR during the read time of two pixels, as shown in FIG. 3A, for example. During the read time of these two pixels, the RD pulse generator 9 supplies the potential of the reset voltage RD to the reset gate 12 as a value lower than the normal voltage by ΔV, as shown in FIG. 3B, for example. At this time, as shown in FIG. 3C, the voltage supplied to the amplification unit 14 has a value ΔV lower than the normal reset voltage RD, and the reference pulse R ₁ is generated.

Then, the CCD 1 supplies the read signal in which the reference pulse is inserted as described above to the CDS 2. CDS
2 is based on the clip pulse SHP and the sample hold pulse SHD shown in FIGS. 3 (d) and 3 (e).
The read signal from the CCD 1 is subjected to correlated double sampling and output as an image pickup signal. This imaging signal has a sample hold voltage R2 corresponding to the reference pulse R ₁ , as shown in FIG. The sample hold voltage R ₂ becomes ΔV which is a value obtained by subtracting the reference pulse R ₁ from the value of the reset voltage RD described above.

Now, the operation of this image pickup apparatus will be described.
At this time, the light from the subject is supplied to the CCD 1, the light is converted into electric charges, the electric charges are read out in accordance with a read pulse supplied from the outside, and the reference pulse is inserted as described above. To form a read signal, and the formed read signal is supplied to the CDS 2.

As described above, the CDS 2 performs so-called correlated double sampling on the read signal from the CCD 1 to remove reset noise and the like superimposed on the read signal and supplies it to the gain control amplifier 3. The gain control amplifier 3 adjusts the level of the read signal from the CDS 2 based on the feedback signal from the error amplification unit 7 as described above, and supplies it to the video amplifier 5. The video amplifier 5 amplifies the read signal supplied from the gain control amplifier 3 and supplies the image pickup signal to the output terminal 4 and the detection unit 6.

The detection section 6 is a video amplifier 5 corresponding to the reference voltage from the image pickup signal supplied from the video amplifier 5, that is, the sample hold voltage R2 from the above-mentioned CDS2.
Output voltage is extracted and supplied to the error amplifier 7. The error amplification unit 7 compares the reference voltage from the detection unit 6 with the reference voltage, obtains an error, and supplies it as a feedback signal to the gain control amplifier 3.

When the temperature changes, the gains of the output amplifier 15, the CDS 2, the video amplifier 5, etc. of the CCD 1 change. At this time, the reset voltage RD supplied to the reset gate 12 of the CCD 1 is constant, but the level of the reference voltage detected by the detector 6 changes. For example, when the temperature rises, the level of the reference voltage rises, and when the temperature falls, the level of the reference voltage falls.

When the reference voltage rises, the error obtained by the error amplifying section 7 becomes large, and the error amplifying section 7 forms a feedback signal so as to reduce the error and supplies the feedback signal to the gain control amplifier 3 and the gain control amplifier 3 Adjust the gain of. Specifically, when the level of the reference voltage increases, the gain of the gain control amplifier 3 is reduced, and when the level of the reference voltage decreases, the gain of the gain control amplifier 3 is increased.

As described above, the gain control amplifier 3
When the gain changes, the error obtained by the error amplification unit 7 becomes smaller, and the error amplification unit 7 forms a feedback signal so as to suppress the gain adjustment of the gain control amplifier 3 and supplies the feedback signal to the gain control amplifier 3. Adjustment of the gain of the gain control amplifier 3 is suppressed.

Thus, in this image pickup apparatus, the level of the image pickup signal to be output is made constant by controlling the gain of the gain control amplifier 3 as described above.

As a result, this image pickup apparatus can keep the level of the image pickup signal output even if the temperature changes, and can perform more accurate temperature compensation than the conventional image pickup apparatus. Further, in this image pickup device, the reference gate is inserted at the subsequent stage of the conventional CDS by generating the reference pulse by the reset gate of the output amplifier required for the output part of the CCD and inserting the reference pulse. It is possible to perform temperature compensation more accurately than an image pickup device, and it is not necessary to provide a reference pulse generation unit that generates a reference pulse or a reference pulse insertion unit that inserts a reference pulse into a read signal. Can be reduced.

Another imaging device to which the present invention is applied is
For example, as shown in FIG. 4, a CCD 20 that reads out an electric charge according to light from a subject, inserts a reference pulse and outputs a read signal, a CDS 21 that removes noise of a read signal from the CCD 20, and a read from the CDS 21. A gain control amplifier 23 that adjusts the level of the signal and outputs the image pickup signal via the output terminal 22, and an output (hereinafter referred to as a reference voltage) corresponding to the reference pulse from the image pickup signal from the gain control amplifier 23 are extracted. , A reference voltage is compared with a reference voltage to obtain an error, and a detection unit 24 that supplies a feedback signal based on the error to a gain control amplifier 23 and a reset that supplies a reset signal (hereinafter referred to as a reset gate pulse) to the CCD 20. Gate pulse generator (hereinafter referred to as RG pulse generator)
25 and an RD pulse generator 26 for supplying a reset voltage to the CCD 20.

The CCD 20 switches the reset voltage from the RD pulse generator 26 based on the reset gate pulse from the RG pulse generator 25 to generate a reference pulse, which is inserted into the read signal and output. It is like this.

The output unit for outputting the read signal of the CCD 20 is, for example, as shown in FIG.
The reset terminal 30 to which the reset gate pulse RG is supplied, the terminal 31 to which the reset voltage RD from the RD pulse generator 26 is supplied, and the reset gate pulse RG from the reset terminal 30 switch the reset voltage RD. Reset gate 32 and CCD 2
0, a read terminal 13 to which a charge is supplied from a transfer register (not shown), an amplifying section 14 that holds the charge from the read terminal 13 and outputs the held charge as a read signal, and an amplifying section 14 An output amplifier 15 that amplifies and outputs the read signal from is output.

In the output section of the CCD 1 shown in FIG.
Although the reset gate 12 is composed of a normal FET, the reset gate 32 is composed of a so-called MOS-FET in the output part of the CCD 20. In the output section of the CCD 1 shown in FIG. 2 described above, the voltage supplied to the amplification section 14 is the reset voltage RD switched by the reset gate 12, but this CCD
In the output section of 20, the voltage is RG−V _GS which is the difference between the reset gate pulse RG supplied to the reset gate 32 and the gate-source voltage V _GS .

Further, the RG pulse generator 25, as shown in FIG. 6, for example, includes a switch 40 for switching between the ground voltage V ₀ and the reference pulse voltage VR -V ₁ in accordance with a switching pulse supplied from the outside, An output of the switch 40 according to the reset gate signal, a switch 41 for switching the reset voltage VR, and a buffer 42 for supplying the output of the switch 41 to the reset terminal 30 are provided.

The switch 40 has a ground voltage V ₀ and a reference pulse voltage VR − in response to a switching pulse supplied from the outside.
V1 is switched and supplied to the switch 41, and the switch 4
1 switches the output of the switch 40 and the reset voltage VR according to the reset gate signal and supplies the output to the buffer 42. The buffer 42 supplies the output of the switch 41 to the reset terminal 30 described above.

As a result, the RG pulse generating section 25, as shown in FIG. 7A, for example, has a reset gate pulse composed of a reset voltage VR having a constant cycle and a reference pulse R _{3 of a} level V 1 lower than the reset voltage VR. RG is generated and supplied to the reset terminal 30. On the other hand, the RD pulse generator 26 supplies a constant voltage to the reset gate 32 as shown in FIG. 7B, for example.

Further, from the reset gate 32 to the amplifier 34
The voltage supplied as the reference pulse R ₄ in FIG.
As shown in FIG.
It becomes V1 lower than the output VR -V _GS.

The CCD 20 supplies the read signal with the reference pulse inserted as described above to the CDS 21. CDS21
Is the clip pulse S shown in FIGS. 7 (d) and 7 (e).
C based on HP and sample hold pulse SHD
The read signal from the CD 20 is subjected to correlated double sampling and output as an image pickup signal. This image pickup signal has a sample hold voltage R ₅ corresponding to the reference pulse R ₄ , as shown in FIG. The sample hold voltage R ₅ is the output VR −V _GS of the reset gate 32 at the time of normal reset.
The reference pulse _{R 4 (= VR -V GS -V1} ) is a value obtained by subtracting V1 from.

The operation of this image pickup apparatus will be described below.
The light from the subject is supplied to the CCD 20, and C
The CD 20 converts light from a subject into electric charges and reads the electric charges according to a read pulse or the like supplied from the outside,
A reference pulse is inserted to form a read signal, and the formed read signal is supplied to the CDS 21.

The CDS 21 performs so-called correlated double sampling on the read signal from the CCD 20, removes reset noise and the like superimposed on the read signal, and supplies it to the gain control amplifier 23. The gain control amplifier 23 adjusts the level of the read signal from the CDS 21 based on the feedback signal from the detection unit 24 and supplies the image pickup signal to the output terminal 22 and the detection unit 24.

The detection section 24 extracts the reference voltage from the image pickup signal from the gain control amplifier 23, that is, the output voltage of the gain control amplifier 23 corresponding to the voltage R3 of the above-mentioned reference pulse, compares it with the reference voltage, and determines the error. It is obtained and supplied to the gain control amplifier 23 as a feedback signal.

When the temperature changes, the gains of the output amplifier 35, the CDS 21, the video amplifier 35, etc. of the CCD 20, for example, change. At this time, the voltage of the reset gate pulse RG supplied to the reset gate 32 of the CCD 20 does not change and the level of the reference pulse R3 is constant, but the level of the reference voltage detected by the detector 24 changes. For example, when the temperature rises, the level of the reference voltage rises, and when the temperature falls, the level of the reference voltage falls.

When the reference voltage rises, the error obtained by the detection section 24 increases, and the detection section 24 forms a feedback signal so as to reduce the error and supplies the feedback signal to the gain control amplifier 23.
Adjust the gain of 3. Specifically, when the level of the reference voltage is increased, the gain of the gain control amplifier 23 is decreased, and when the level of the reference voltage is decreased,
The gain of the gain control amplifier 23 is increased.

As described above, the gain control amplifier 2
When the gain of 3 changes, the error obtained by the detection unit 24 becomes small, and the detection unit 24 forms a feedback signal so as to suppress the adjustment of the gain of the gain control amplifier 23 and supplies it to the gain control amplifier 23.
Adjustment of the gain of the gain control amplifier 23 is suppressed.

Thus, in this image pickup apparatus, the level of the image pickup signal to be output is made constant by controlling the gain of the gain control amplifier 23 as described above.

As a result, this image pickup apparatus can keep the level of the image pickup signal output even when the temperature changes, and can perform more accurate temperature compensation than the conventional image pickup apparatus. Further, in this image pickup device, the reset gate of the output amplifier required for the output portion of the CCD generates a reference pulse and inserts it into the read signal, so that the temperature compensation can be performed more accurately than before. With
A reference pulse generator that generates another reference pulse, or
Since it is not necessary to provide a reference pulse inserting section for inserting a reference pulse into the read signal, the cost of the device can be reduced.

The technical idea of the present invention is not limited to the above-mentioned embodiment, but for example, in the above-mentioned embodiment, the reference gate is generated by the reset gate of the output part of the CCD. It is needless to say that the generation of the reference pulse can be appropriately changed by, for example, having a configuration having a reference pulse generation unit that generates the reference pulse outside the CCD.

[0065]

In the image pickup device according to the present invention, the image pickup device reads out the electric charge according to the light from the subject, inserts the reference signal from the reference signal generating means and outputs the read signal, and the processing means outputs the read signal. The read signal from the device is subjected to predetermined processing to output an image pickup signal, the detecting means detects a change in the level of the output corresponding to the reference signal of the processing means, and the adjusting means is based on the detected output of the detecting means. By adjusting the output level of, the level of the image pickup signal to be output can be made constant regardless of the temperature, and the level of the image pickup signal can be compensated more accurately than in the conventional case.

Further, in the image pickup apparatus according to the present invention, the reference signal generating means changes the reset voltage and controls the gate voltage to control the switching timing of the gate means of the solid-state image pickup device to generate the reference signal. By inserting the read signal into the read signal, it is possible to perform temperature compensation more accurately than before, and reduce the number of parts to reduce the cost.

Further, in the image pickup apparatus according to the present invention, the reference signal generating means changes the gate voltage, and the switching timing of the gate means of the solid-state image pickup device is controlled to generate the reference signal and insert it into the read signal. As a result, it is possible to perform accurate temperature compensation as compared with the conventional one, and
It is possible to reduce the number of parts and reduce the cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an image pickup apparatus to which the present invention has been applied.

FIG. 2 is a circuit diagram showing a specific configuration of an output section of a charge-coupled device that constitutes the image pickup apparatus.

FIG. 3 is a timing chart showing operation waveforms of the image pickup apparatus.

FIG. 4 is a block diagram showing a configuration of another imaging device to which the present invention has been applied.

FIG. 5 is a circuit diagram showing a specific configuration of an output section of a charge-coupled device that constitutes the image pickup apparatus.

FIG. 6 is a circuit diagram showing a specific configuration of an RG pulse generation circuit that constitutes the imaging device.

FIG. 7 is a timing chart showing operation waveforms of the image pickup apparatus.

FIG. 8 is a block diagram showing a configuration of a conventional imaging device.

[Explanation of symbols]

 1,20 CCD 2,21 CDS 3,23 Gain control amplifier 4,22 Output terminal 5 Video amplifier 6,24 Detection section 7 Error amplification section 8 RG pulse generation section 9 RD pulse generation section 10,30 Reset terminal 11,31 terminal 12, 32 Reset gate 13, 33 Read terminal 14, 34 Amplifying section 15, 35 Output amplifier 25 RG pulse generating section 26 RD pulse generating section 40, 41 Switch 42 Buffer

Claims (8)

[Claims] 1. A reference signal generating means for generating a reference signal, an image pickup device for reading out an electric charge according to light from a subject, inserting the reference signal from the reference signal generating means and outputting a read signal, Processing means for performing a predetermined process on a read signal from the image pickup device to output an image pickup signal, detection means for detecting a change in output level of the processing means corresponding to the reference signal, and detection output of the detection means And an adjusting unit that adjusts the level of the output of the processing unit based on the above. 2. The image pickup apparatus according to claim 1, wherein the processing unit includes an amplification unit that amplifies a read signal from the image pickup device. 3. The image pickup apparatus according to claim 1, wherein the adjusting unit includes a level adjusting unit that adjusts a level of a read signal from the image pickup device and supplies the read signal to the processing unit. 4. The image pickup apparatus according to claim 1, wherein the image pickup element is a solid-state image pickup element. 5. The image pickup apparatus according to claim 4, wherein the processing unit includes a removing unit that removes a DC component superimposed on a read signal from the solid-state image sensor. 6. The image pickup apparatus according to claim 5, wherein the removing unit includes a sampling unit that performs correlated double sampling on the read signal from the solid-state image pickup device. 7. The solid-state imaging device includes: read control means for reading out electric charges according to light from a subject; and holding means for holding the electric charges from the read controlling means and outputting the held electric charges as a read signal. And a gate means for resetting the holding means by switching the reset voltage based on the gate voltage and supplying the reset voltage to the holding means, wherein the reference signal generating means varies the reset voltage and controls the gate voltage. The reference signal is generated and inserted into the read signal by controlling the switching timing of the gate means.
The imaging device described. 8. The solid-state imaging device comprises: read control means for reading out electric charge according to light from a subject; and holding means for holding the electric charge from the read control means and outputting the held electric charge as a read signal. A gate means for resetting the holding means by switching a reset voltage on the basis of the gate voltage and supplying the reset voltage to the holding means, wherein the reference signal generating means varies the gate voltage and The image pickup apparatus according to claim 4, wherein the reference signal is generated and inserted into a read signal by controlling switching timing.