JPH02190085A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To always obtain an optimum picture by deciding whether or not a minimum value and a maximum value of a pickup signal data read out of a picture memory are within a dynamic range of a preset video signal output so as to control a gate voltage and a storage time of an input gate of a charge coupled element. CONSTITUTION:A detection storage means 24 detects respectively a minimum value and a maximum value of a pickup signal data and stores the value and a number of a photodetector representing the value. A deciding means 25 decides whether or not a minimum value and a maximum value of a pickup signal data are within a dynamic range of a video signal. A control means 27 controls respectively a gate voltage and storage time of the input gate of a charge coupled element 22 corresponding to a decision output of the deciding means 25 to locate the pickup signal within a range of white and black levels of the display level. Thus, the entire temperature range is displayed properly in a display pattern automatically to display an optimum display picture.

Description

[Detailed Description of the Invention] [Summary] Each of a plurality of regularly arranged light receiving elements
Regarding an identification TA imager that uses a solid-state image sensor, which photoelectrically converts infrared light from an image object into a charge-coupled device and then transfers and reads it out, it automatically adjusts to the optimal display range in a short time. With the aim of always obtaining the optimum image, the image signal extracted from the solid-state image sensor, which stores and transfers the signal charge obtained by charging and converting each of the plurality of light receiving elements using a charge-coupled device, is used as the image signal. In a solid-state image device configured to store data in a memory and then output it, the minimum value and maximum value of the image signal data read out from the image memory are respectively detected, and those values and the numbers of the light receiving elements indicating those values are stored. a detection/storage means for detecting, a determining means for determining whether or not the minimum value and maximum value stored by the detection/storage means fall within a preset dynamic range of the video signal output; a memory in which voltage vs. current characteristic data for each of the light receiving elements is stored in advance; and a determination output from the determination means indicating that at least one of the minimum value and maximum value exceeds the dynamic range. and control means for generating a control signal for controlling at least one of a gate voltage and an accumulation time of an input gate of the charge-coupled device based on the characteristic data read from the memory and supplying the generated control signal to the charge-coupled device. Configure it to do so.

(Industrial Application Field) The present invention relates to a solid-state imaging device, and more particularly, the present invention relates to a solid-state imaging device, and in particular, charges obtained by photoelectrically converting infrared light from an object to be imaged by each of a plurality of regularly arranged light-receiving elements. The present invention relates to a solid-state image device using a solid-state image sensor that is injected into a coupling element and then transferred and read out.

IRCCD is a solid-state image sensor that photoelectrically converts infrared light from an imaging target using each of a plurality of light receiving elements, injects the resulting charge into a charge-coupled device (COD), transfers it, and reads it out.
(Infrared Charae Coupled
Qevice). An infrared a imaging device using this IRCCD is being widely applied in the industrial field because it can accurately grasp the temperature distribution of an object to be imaged.

In this case, in order to obtain an appropriate display image regardless of the experience of the person concerned, it is necessary for the infrared imaging device to be able to automatically set optimal operating conditions. Therefore, the input gate is opened so that the black level indicating the lowest humidity falls within the display level range, and the accumulation time is shortened so that the white level indicating the highest temperature falls within the display level range.
This is required for solid-state imaging devices (infrared imaging devices).

[Conventional technology]

FIG. 6 shows a block diagram of an example of a conventional solid-state imaging III device. In the figure, reference numeral 11 denotes a light receiving array, in which a plurality of infrared light receiving elements are two-dimensionally arranged. 12 is a horizontal scanning CCD
Then, the charge for one line of the light receiving array 11 is serially transferred in the horizontal direction, and is transferred to the A/D converter 1 through the output amplifier 13.
Output to 4.

The A/D converter 14 converts the input signal into a digital signal to generate pixel data, and supplies this to the image memory 15 for storage. Reference numeral 16 denotes an offset/gain correction memory in which correction data for correcting and equalizing variations in offset and gain (sensitivity) of each infrared light receiving element constituting the light receiving array 11 is measured in advance and stored therein.

17 is an *n circuit which performs calculations on the pixel data from the image memory 15 and the correction data, generates pixel data whose offset and gain have been corrected, and outputs the pixel data to the output terminal 18.

In this conventional solid-state imaging device, the imager assumes the temperature of the object to be imaged, manually sets the input gate voltage and accumulation time to determine the low and high temperature levels, and performs horizontal scanning C
The charge m transferred in the horizontal direction was controlled by the CD 12.

(Problem to be Solved by the Invention) However, in the conventional solid-state 11HI device described above, the input gate voltage and accumulation time are manually set, so when it is unclear what the object is to be imaged or when the imager If the operator is inexperienced, it will take time to adjust the above two parameters in order to obtain the optimum two wheels, and the imaging opportunity will be missed.

Furthermore, when the object changes, an adjustment operation is required to set the above two parameters, which is complicated.

The present invention has been made in view of the above points, and is capable of achieving R in a short time.
An object of the present invention is to provide a solid-state imaging device that can automatically adjust to an overdisplayed range and always obtain an optimal image.

[Means to solve the problem]

FIG. 1 shows a block diagram of the principle of the present invention. In the same figure, 21
22 is a charge-coupled device that stores and transfers signal charges from the light-receiving device 21; and 23 is an image memory that stores image signals from the charge-coupled device 22.

In the solid-state imaging device having such a configuration, the present invention provides detection/storage means 241, determination means 25. A memory 26 and a control means 27 are provided. The detection/storage means 24 detects the minimum value and maximum value of the imaging signal data, respectively, and stores these values and the numbers of the light receiving elements indicating these values.

The determining means 25 determines whether the above minimum value and maximum value fall within the dynamic range of the video signal output. The memory 26 stores voltage versus current characteristic data of the light receiving element.

1IItI1 means 27 controls at least one of the gate voltage and the storage time of the input gate of the charge-coupled device 22.
A 4tm signal is generated and supplied to the charge coupled device 22.

[Function] The voltage-current characteristics when the light receiving element 21 is connected to the charge coupled device 22 are as shown in FIG.

In the figure, a solid line I shows the voltage-current characteristics of the light receiving element 21, and broken lines ma and mb show the voltage-current characteristics of the input gate of the charge-coupled device 22. Voltage-current characteristics engineering and Ira
(or In) is the intersection point of V, which indicates the current flowing into the charge coupled device 22.

Now, when the gate voltage is increased with respect to the input gate of the charge-coupled device 22, the voltage-'iIi current characteristic of the input gate is shown by the broken line Ia, the voltage-current characteristic is shifted in parallel from l[a to the left and is shown by mb. As a result, the inflow current increases. Voltage versus current characteristic data obtained by previously measuring the amount of change for all of the light receiving elements 21 is stored in the memory 26.

When the control means 27 receives a judgment output from the judgment means 25 indicating that the black level of the display level is smaller than the minimum value of the imaging signal data, the control means 27 generates a control signal that sets the gate voltage of the input gate to human. . This increases the current injected into the input gate, thereby increasing the output signal level of the charge-coupled device 22.

On the other hand, when the control means 27 receives a determination output from the determination means 25 indicating that the white level of the display level is larger than the maximum value of the image signal data, the signal charge accumulated in the charge-coupled device 22 is Since it is proportional to time, storage v4
Generates and outputs an il[l signal that shortens the time. As a result, the output signal level of charge-coupled device 22 decreases.

In this way, the gate voltage and storage time of the input gate of the charge-coupled device 22 are respectively set to Ml! By doing so, the image signal can be kept within the range between the white level and the black level of the display level (dynamic range of video output).

〔Example〕

FIG. 3 shows a block diagram of one practical example of the present invention.

In the figure, the same components as in FIG. 1 are denoted by the same reference numerals, and their explanations will be omitted. In FIG. 3, reference numeral 31 denotes a photodiode for receiving infrared light, a plurality of which are regularly arranged and constitute the light receiving element 21. In FIG.

The cathode of the photodiode 31 is a charge coupled device (CO
D) is connected to the input diode 32- of 22. In addition, C0D22 has an input gate 33.degree. storage gate 34.
Transfer gates 35, etc. are formed, and shift registers 36. An output amplifier 37 is formed.

In FIG. 3, from the Il image object to the photodiode 31
The infrared light incident on the is converted here.

The signal charge thus obtained is supplied to an input diode 32 provided in a one-to-one correspondence with the light-receiving element 31 of one line. It is accumulated in the potential well of the semiconductor substrate directly below.

Then, after a predetermined period of time has elapsed, the potential of the semiconductor substrate directly under the transfer gate 35 is lowered, so that the above iI
The product signal charge passes through the semiconductor substrate portion directly below the transfer gate 35 and is transferred to the shift register 36. Here, the amount of signal charge transferred from the transfer gate 35 is
The amount corresponds to the difference between the potential directly below each of the transfer gates 35 and 35.

The signal 1 direction transferred to the shift register 36 is sequentially shifted in the horizontal direction, passes through the output amplifier 37, and is supplied to the A/D converter 38, where the digital signal (
1! il image signal data) and then input to the image memory 23 and stored.

The image signal data read out gradually from the image memory 23 is input to the computer 39. The computer 39 includes the detection/storage means 241 and the determination means 25 and 11311.
As will be described later, the maximum value, the minimum value, and the element number of the photodiode 31 indicating the maximum value and the element number of the photodiode 31 are stored in a built-in memory, and the display level range is set in advance. If it is outside the range, read the characteristic data from the memory 26 as necessary and perform Ill, and adjust the input gate so that the maximum value and minimum value are within the display level range. A voltage control signal and an accumulation time control signal are made into one.

The above input gate voltage control signal is applied to the input gate 33 via the input gate driver 40. on the other hand,
The storage time control signal is applied to the storage gate 34 via the storage gate driver 41. Thereby, the level of the image signal taken out from the output amplifier 37 is controlled.

Next, the operation of the computer 39 will be further explained with reference to the flowchart shown in FIG. 4. In FIG. After the two memories A and B are cleared, one image signal data is read from the image memory 23 in step 102.

Subsequently, the computer 39 determines in step 103 whether the read image signal data is the minimum value by comparing it with the image signal data up to that point, and if it is not the minimum value, in the next step 104, it compares the data up to that point. Determine whether it is the maximum value or not, and if it is not the maximum value, proceed to step 10.
In step 4, it is determined whether or not all the imaging signal data has been compared, and if all the data has not been compared yet, the process returns to step 102.

When the minimum value is determined in step 103, the element number of the photodiode 31 showing the minimum value and the signal level of the minimum value are stored in the memory A in step 106, and then the process proceeds to step 105. On the other hand, when it is determined in step 104 that the value is the maximum value, the element number of the photodiode 31 showing the maximum value and the signal level of the maximum value are stored in the memory B in step 101, and then the process proceeds to step 105. Thereafter, the processing operations of steps 102 to 107 described above are performed for all image signal data in the image memory 23. Therefore, steps 102 to 101 constitute the detection/storage means 24.

Next, the computer 39 determines whether the minimum value stored in memory A is smaller than the display black level in step 108, and if the minimum value is greater than the display black level, the minimum value is stored in memory B in step 109. A determination is made as to whether the maximum value is greater than the display white level. Therefore, the above steps 108 and 109 are performed by the above-mentioned determining means 25.
It consists of

If it is determined in step 108 that the minimum value is smaller than the display black level, the computer 39 takes in the characteristic data of the photodiode 31 with the r number indicating the minimum value from the memory 26 in the next step 11G, and ((display black level)
- (Minimum ftJ))

Further, when it is determined in step 109 that the maximum value is greater than the display white level, the computer 39 proceeds to the next step 111, for example (display white level) x (current accumulation time).
/(maximum value) is performed to generate storage time control data that shortens the storage time from the current one, and supplies this to the driver 41.

Therefore, steps 110 and 111 described above constitute the control means 27 described above. In this way, when the process of step 109 or 111 is completed, the computer 3
9 returns to step 101 again.

As a result of the above processing operations, the image signal data stored in the image memory 23, for example, as shown in FIG. If the maximum value of the imaging signal data is greater than the display white level, the step 110
IIJ whose input gate voltage becomes human by processing in
Because tel is performed, the image signal data of element number @1 becomes human than the display black level as shown in FIG. Become).

Furthermore, since control is performed such that the accumulation time is shortened by the processing in the next step 111, as shown in FIG. 5(C).
As shown in , the level of the image signal data of each element number is made small, but because the input gate voltage is controlled, the maximum value of the element number N is still higher than the display white level. .

In this case, the computer 39 performs the processing operation from step 101 again, so control is performed to shorten the accumulation time by the processing in step 111 again. The image signal data is also smaller than the display white level, as shown in FIG. 5(D), and the levels of all layer image signal data fall within the range of the display white level and the display black level.

[Effects of the Invention] As described above, according to the present invention, dance! & Since the signal can be automatically kept within the display level between white and black levels, even if you do not know the temperature range of the object to be imaged,
The entire temperature range can be displayed properly on the display screen automatically, and no technical skill is required when taking images, so anyone can display the optimal display image, and the optimal image can be automatically displayed. Since images can be obtained, there is no need to make adjustments even if the object to be imaged changes, and its operability is good.

[Brief explanation of the drawing]

Fig. 1 is a principle block diagram of the present invention, Fig. 2 is a voltage-current characteristic diagram, Fig. 3 is a block diagram of an embodiment of the present invention, and Fig. 4 is an operation of the crab portion of an embodiment of the present invention. 5 is a diagram for explaining the initial control according to the present invention, and FIG. 6 is a block diagram of a conventional example. 27 is an 'IAm means, 32 is an input diode, 33 is an input gate, 34 is a storage gate, 35 is a transfer gate, and 40.41 is a driver. Patent applicant: Fujitsu Ltd. In the figure, 21 is a light receiving element, 22 is a charge-coupled device, 23 is an image memory, 24 is a detection/storage means, 25 is a judgment means, 26 is a memory, and the seven principles of the old moon Figure 7 F #! ::Fink diagram 3rd of January's all-at-once transformation series
Diagram practice morning 1: Gate control action ecstasy Figure 5

Claims (1)

[Claims] An imaging signal taken out from a solid-state image sensor that stores and transfers signal charges obtained by photoelectric conversion by a plurality of light receiving elements (21) using a charge-coupled device (22). In a solid-state imaging device configured to output data after storing it in an image memory (23), the minimum value and maximum value of the imaging signal data read out from the image memory (23) are respectively detected, and these values are detection/storage means for storing the number of the light receiving element shown (
24), and determination means (2) for determining whether the minimum value and maximum value stored by the detection/storage means (24) fall within a preset dynamic range of the video signal output.
5); a memory (26) in which voltage vs. current characteristic data for each of the plurality of light receiving elements (21) is stored in advance; and at least the minimum value and the maximum value from the determining means (25). At least one of the gate voltage and the accumulation time of the input gate of the charge-coupled device (22) is determined based on the determination output that one exceeds the dynamic range and the characteristic data read from the memory (26). the charge coupled device (22) by generating a control signal to control the charge coupled device (22);
A solid-state image device characterized by comprising: a control means (27) for supplying a signal to a solid-state image device.