JPH05300438A - Image pickup device - Google Patents

Abstract

PURPOSE:To generate corrected data with a fixed judge reference in a short time by automatically generating sensitivity correction data at the image pickup device to perform image pickup by using a multi-element photoelectric conversion device. CONSTITUTION:An arithmetic means 20 generates the sensitivity correction data, specifies a detective photodetector and generates replacement data from the output electric signals of a multi-element photoelectric conversion device 10. A corrected data storage part 30 respectively stores the sensitivity correction data and the replacement data corresponding to the defective photodetector. Then, a correcting arithmetic circuit 40 outputs corrected video signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device, and more particularly, to an image pickup device for picking up an image using a multi-element photoelectric conversion device.

In a multi-element photoelectric conversion device, that is, in an image pickup apparatus having a light-receiving device in which a plurality of light-receiving elements are linearly arranged at a constant pitch, a TDI (Time Delay & Integration) process has been performed due to recent demand for improved sensitivity. There is something to do.

In this TDI processing, for example, optical scanning is performed in a direction orthogonal to the arrangement direction of a plurality of light receiving elements in each column, and electric signals extracted from each of the plurality of light receiving elements are amplified by corresponding amplifiers and further delayed, The output signals of the corresponding light receiving elements are added and combined. As a result, the signals at the same scanning point of the subject are added and synthesized to have a large level, but the noise does not change to a large level even with the above addition because the noise changes randomly. An improved video signal can be obtained.

In the image pickup apparatus which performs such TDI processing,
It is necessary to efficiently acquire data for correcting the sensitivity variations of a plurality of light receiving elements.

[0005]

2. Description of the Related Art FIG. 4 shows a block diagram of an example of a conventional image pickup apparatus. In the figure, the multi-element photoelectric conversion device 1 has a configuration in which a plurality of rows of a plurality of light receiving elements arranged at a constant pitch are arranged, and light from an object is arranged in a plurality of rows by a scanning mirror (not shown). The light is scanned and incident in the direction orthogonal to the arrangement direction of the light receiving elements.

An electric signal obtained by photoelectrically converting light from a subject by each of a plurality of light receiving elements is amplified by an amplifier 2 provided for the light receiving element, and then A / D converted provided for the light receiving element. It is converted into digital data (image data) separately by the device 3. This digital data is supplied to the calculation unit 6 via the element switching unit 4, and the signal obtained by delaying the signal from the light receiving element in the adjacent column scanned last time by one line and the signal obtained by this scanning are obtained. The added signal is added and combined to obtain the image data subjected to the TDI processing. This image data is converted into an analog video signal by the D / A converter 7.

If any of a large number of light receiving elements constituting the multi-element photoelectric conversion device 1 is defective, the output signal of the defective light receiving element is different from the normal one, and therefore the above TDI processing is executed as it is. Then, on the contrary, the S / N may be lowered. Further, if there is sensitivity variation among the light receiving elements, the display image will not be displayed uniformly even if a uniform subject is imaged.

Therefore, in the conventional image pickup apparatus, an object having a uniform background is imaged in advance to measure the sensitivities of the respective light receiving elements, and the sensitivity for performing the correction calculation in the arithmetic unit 6 so that the sensitivities of all the light receiving elements are the same. The correction data is created corresponding to the light receiving element and stored in the data storage unit 5, and for the defective light receiving element whose sensitivity is equal to or lower than a predetermined value, data for replacing the output data is created and stored in the data storage unit 5. To do.

Then, the data from the defective light receiving element is switched to the replacement data from the data storage section 5 by the element switching section 4, and the calculation section 6 performs the correction calculation based on the sensitivity correction data from the data storage section 5. This allows
The conventional device has TDI without being affected by the defective light receiving element.
Processing can be executed, and sensitivity variations can be corrected.

[0010]

However, in the conventional device, it takes time because the operator sequentially determines all the light receiving elements for the defective light receiving elements, and the determination criteria are different depending on the operator, which is ambiguous. Even if the same operator is used, the determination standard may change with time. Furthermore, even if the sensitivity correction data is accurately set and the imaging device is shipped, the sensitivity changes due to aging, so the sensitivity deteriorates due to aging, and the correction data does not match, and as a result, the sensitivity of the light receiving element There are problems such as deterioration.

The present invention has been made in view of the above points,
An object of the present invention is to provide an imaging device that solves the above problems by automating sensitivity correction and the like.

[0012]

FIG. 1 is a block diagram showing the principle of the present invention. As shown in the figure, the present invention comprises a multi-element photoelectric conversion device 10, a calculation means 20, a correction data storage section 30, and a correction calculation circuit 40. The multi-element photoelectric conversion device 10 has a plurality of light receiving elements arranged in a predetermined direction and photoelectrically converts light from a subject.

The calculating means 20 performs generation of sensitivity correction data, identification of defective light receiving elements, and generation of replacement data from the output electric signal of the multi-element conversion device 10. The correction data storage unit 30 stores the sensitivity correction data obtained by the calculating unit 20 and the replacement data for the defective light receiving element, respectively. The correction arithmetic circuit 40 outputs a video signal which has been subjected to a correction arithmetic operation from the data from the correction data storage section 30 and the electric signal from the arithmetic means 20.

The arithmetic means 20 includes an arithmetic unit 24 for performing arithmetic operations according to a predetermined processing algorithm, an A / D converter 21 for converting an electric signal from the multi-element photoelectric conversion device 10 into digital data, and an A / D conversion. An element array switching unit 22 that switches the parallel output digital data of the device 21 for each element array based on the output signal of the arithmetic unit 24, and a data storage unit 23 that stores the output digital data of the element array switching unit 22 as sensitivity data. Become, operation unit 2
Reference numeral 4 generates the sensitivity correction data based on the sensitivity data read from the data storage unit 23, and also generates replacement data to replace the output data of the defective light receiving element.

[0015]

According to the first aspect of the present invention, the sensitivity correction data and the replacement data for the defective light receiving element are automatically generated by the calculation means 20 based on the electric signal from the multi-element photoelectric conversion device 10, and the correction data is generated. It can be stored in the storage unit 30.

According to the second aspect of the invention, the computing means 2
Since 0 stores the sensitivity data of each light receiving element of the multi-element photoelectric conversion device 10 in the data storage unit 23, the calculation unit 24 generates sensitivity correction data, determines a defective light receiving element, and weights the correction calculation value (narcissus). / Removal of fixed noise such as shading), and virtual value setting for defect removal.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 shows a block diagram of an embodiment of the present invention. In the figure, the same components as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. In FIG. 2, the multi-element photoelectric conversion device 10 includes a first element array in which N photodiodes (N is an integer of 2 or more) are arranged in a straight line at a constant pitch in the vertical direction in the figure as photodiodes 11 which are light receiving elements. , Photodiode 12
Is formed on the substrate 13 in parallel with the first element row and N second element rows are arranged at a constant pitch, and each of the N photodiodes 11 and 12 has a one-to-one correspondence. The shift register is formed by a charge transfer device (CCD). The photodiodes 11 and 12 receive, for example, infrared light and perform photoelectric conversion.

The optical scanning is carried out in the horizontal direction in the figure, and the photodiodes 11 and 12 simultaneously receive the light from the object for each line.
Takes an image of the subject position imaged by the photodiode 11 one line before, and the photodiode 11 takes an image of a new subject position. Therefore, the TDI processing can be performed by adding and synthesizing the signal obtained by delaying the output electric signal of the photodiode 11 by one line and the output electric signal of the photodiode 12.

The electric signals photoelectrically converted by the photodiodes 11 and 12 are taken out serially and in parallel with each other through the shift register, respectively.
After being respectively amplified by one amplifier 51, they are respectively analog-digital converted by the two A / D converters 21 and converted into digital data.

The output digital data of the A / D converter 21 is digital data obtained by the output of the first element array by the photodiode 11 by the element array switching unit 22 and digital data by the output of the second element array by the photodiode 12. One of them is selected and transferred to the central processing unit (CPU) 54, while it is input and stored in the random access memory (RAM) 52 or 53. The RAMs 52 and 53 respectively constitute the data storage unit 23 described above. Further, the CPU 54 constitutes the arithmetic unit 24 described above.

The CPU 54 operates according to the flow chart shown in FIG. 3 according to a correction command input from the outside through the I / O port 55. In FIG. 3, first, a command determination is performed (step 101), and when it is determined that a correction command is input, the element array switching unit 22 is controlled to A / D convert the output signal of the photodiode 11 of the first element array. The digital data is stored in the RAM 52 as sensitivity data (step 102), and subsequently the A / D converted digital data of the output signal of the photodiode 12 of the second element array is stored in the RAM 53 as sensitivity data (step).
103). At the time of inputting this correction command, the photodiodes 11 and 12 receive light from a subject having a uniform background.

Next, the CPU 54 sequentially reads out the sensitivity data from the RAMs 52 and 53, and when the data value of each of them is a value greatly deviating from the certain value corresponding to the uniform background by exceeding the allowable range, the data is read. It is determined that the output photodiode is a defective element (step 104).
). Then, it is judged whether or not this defective element is two photodiodes adjacent to each other in the first element row and the second element row (step 105), and two photodiodes adjacent in the same position are defective elements. Sometimes, instead of them, the output of another closest photodiode is used instead of the defective element, so that the element number indicating the position of the closest other photodiode is designated as the alternative element number (step 106).

Next, the CPU 54 computes and calculates correction coefficients, that is, sensitivity correction data, in which the sensitivity data are correct and show the same sensitivity, based on the sensitivity data sequentially read from the RAMs 52 and 53 ( Step 107). Further, for the defective photodiodes which are not adjacent to each other at the same position, the CPU 54 calculates and calculates replacement data to be replaced by the output (step 108).
).

Then, the CPU 54 finally reads the sensitivity correction data and the replacement data thus generated as correction data at the time of arithmetic processing, and the RAM 56 of FIG.
(Step 109). This correction data is shown in Figure 2.
It is also possible to monitor with an external monitor device via the I / O port 55 of the above.

As described above, according to the present embodiment, since the human factor does not intervene in the generation of the sensitivity correction data, the determination of the defective element and the generation of the replacement data for the defective element, the correction can be automatically performed. It is possible to shorten the acquisition time of the business data and improve the uniformity.

The above steps 101 to 109 may be carried out periodically or only once before the shipment of the image pickup apparatus. When it is regularly performed, the correction data can be updated in response to the deterioration of the sensitivity of the photodiodes 11 and 12 due to aging, so that the image quality can be kept high for a longer period of time.

The RAM created in this way and also in the RAM
After the correction data is stored in 56, a correction calculation is subsequently performed based on this correction data (step 110).
). That is, in FIG. 2, at the time of normal image pickup, the first array alternately switched and output from the element array switching unit 22.
The digital data (pixel data) based on the output signals of the photodiodes 11 of the element array and the digital data (pixel data) based on the output signals of the photodiodes 12 of the second element array are processed by the arithmetic circuit 41 through the CPU 54.
Is supplied to.

The operation circuit 41 constitutes the above-described correction operation circuit 40 together with the D / A converter 42, and after performing the correction operation (for example, multiplication) between the input image data and the corresponding correction data read from the RAM 56. Then, the TDI process is performed. Thereby, the sensitivity variation is corrected, the data from the defective element is replaced with the data approximate to the data when the defective element is normal, and the SDI is improved by the TDI process. And is supplied to the D / A converter 42. The D / A converter 42 converts the input digital data into a video signal which is an analog signal and outputs it.

The present invention is not limited to the above-described embodiment. For example, the function of the CPU 54 may be reduced depending on the scale of the device, and the arithmetic processing of the correction data may be performed by the external arithmetic processing section. The correction data thus generated may be stored in the RAM 56. Further, although the correction cannot be performed according to the secular change, the ROM 56 may be used instead of the RAM 56 to store the correction data.

[0030]

As described above, according to the first aspect of the invention, since the correction data is automatically generated, the human element does not interfere with the generation of the correction data, and the correction data is not generated. In addition to being able to generate in a shorter time than in the past, since the determination standard is uniform, it is possible to improve the uniformity of the image quality by the unified correction calculation, and according to the invention of claim 2,
Generation of sensitivity correction data, defect determination, generation of replacement data, etc. can be performed with a simple circuit configuration. Further, according to the invention of claim 3, it is possible to always obtain a stable image without quality deterioration irrespective of secular change. Further, according to the invention of claim 4, SDI is improved by TDI processing. It has features such as being able to do.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a configuration diagram of an embodiment of the present invention.

FIG. 3 is a flowchart for explaining the operation of the embodiment of the main part of the present invention.

FIG. 4 is a block diagram of an example of a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Multi-element photoelectric conversion device 11, 12 Photodiode 20 Arithmetic means 21 A / D converter 22 Element sequence switching unit 23 Data storage unit 24 Arithmetic unit 30 Correction data storage unit 40 Correction arithmetic circuit 41 Arithmetic circuit 42 D / A converter 52, 53, 56 Random access memory (RA
M) 54 central processing unit (CPU)

Claims (4)

[Claims] 1. A plurality of light receiving elements are arranged in a predetermined direction,
A multi-element photoelectric conversion device (10) for photoelectrically converting light from a subject, and generation of sensitivity correction data, identification of a defective light-receiving element, and generation of replacement data from an electric signal output from the multi-element photoelectric conversion device (10). A calculation means (20), a correction data storage section (30) in which the sensitivity correction data obtained by the calculation means (20) and replacement data for the defective light-receiving element are respectively stored, and the correction data storage section (30). An image pickup device, comprising: a correction arithmetic circuit (40) for outputting a video signal corrected and calculated from the data from the above and the electric signal from the arithmetic means (20). 2. The arithmetic means (20) is an arithmetic unit (24) for performing arithmetic operations according to a predetermined processing algorithm, and an A / D converter for converting electric signals from the multi-element photoelectric conversion device (10) into digital data. Vessel (21) and the A
An element array switching section (22) for switching the parallel output digital data of the D / D converter (21) for each element array based on the output signal of the arithmetic section (24), and an output digital of the element array switching section (22). And a data storage unit (23) for storing data as sensitivity data,
4) generating the sensitivity correction data based on the sensitivity data read from the data storage unit (23) and generating replacement data to replace the output data of the defective light receiving element. The imaging device described. 3. The image pickup apparatus according to claim 1, wherein the generation of the sensitivity correction data and the replacement data by the calculation means (20) is periodically performed based on a correction command. 4. The multi-element photoelectric conversion device (10) has a structure in which a plurality of light-receiving elements arranged in a predetermined direction are arranged in a direction orthogonal to the predetermined direction. 4. The image pickup device according to claim 1, wherein the optical signal is optically scanned and incident in a direction orthogonal to the predetermined direction, and the output electric signal is subjected to TDI processing by the arithmetic means (20). apparatus.