JP2003009001A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device which is capable of void correction while keeping a sufficient picture quality independently of the size of a void component. SOLUTION: A first void correction device 106 subjects image pickup data from a solid-state imaging device 103 and following light interception data to correction processing based on void pixel position data stored in a void pixel position storage device 107. A second void correction device 110 subtracts corrected light interception data from corrected image pickup data to output a void corrected picture.

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 having a pixel defect correction function of a solid-state image pickup element, and more particularly, a function of correcting a pixel defect at dark called white defect.

[0002]

2. Description of the Related Art As a conventional white defect correction method, image pickup data by a solid-state image pickup device is stored in a memory, and light incident on the solid-state image pickup device is shielded before exposure such as an image processing process or power-on. There is a method of performing subtraction processing on a pixel-by-pixel basis between the light-shielding data to be captured and the image pickup data read from the memory.

This method has a large memory capacity according to the number of pixels of the solid-state image pickup device, but does not require an algorithm for detecting white defects and has a large correction effect.

[0004]

However, when the white defect is corrected by the above conventional method, when the white defect pixel of the solid-state image pickup device has a large white defect component with respect to the dynamic range, the dynamic range is reduced. Therefore, there is a problem that the image quality after white defect correction deteriorates.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide an image pickup apparatus capable of correcting a white defect while maintaining a sufficient image quality regardless of the size of the white defect component. To do.

[0006]

In order to achieve the above object, a first image pickup device according to the present invention comprises a solid-state image pickup device in which photodiodes are two-dimensionally arranged and a CCD is used.
A light shielding unit that conducts / shields incident light to / from the solid-state image sensor by opening / closing the shutter, and resets the charge accumulated in the photodiode of the solid-state image sensor, and then reads out the signal charge accumulated in the photodiode. During at least a part of the period, the signal charge accumulated in the exposure state in which the shutter of the light shielding unit is opened is converted into the first image data from the analog image signal output from the solid-state image sensor as current or voltage. Then, after resetting the electric charge accumulated in the photodiode of the solid-state image sensor, the shutter of the light shielding unit is stored in the closed state during the period in which the signal charge accumulated in the photodiode is read out. A / which converts the analog light-shielding signal whose signal charge is output as current or voltage from the solid-state image sensor into first light-shielding data A conversion unit, a defective pixel position storage unit that stores n (n is a natural number) two-dimensional pixel defect position data existing in the first imaging data and the first light shielding data, and a defective pixel position storage unit. Based on at least a part of the stored pixel defect position data, the correction processing is performed on the first imaging data and the light shielding data to obtain the second imaging data and the second light shielding data, respectively. A first pixel defect correction unit to obtain, an image data storage unit that stores the second image data from the first pixel defect correction unit in pixel units, and a second image data from the first pixel defect correction unit.
The second light-blocking data read from the light-blocking data storage unit is subtracted in pixel units from the second light-blocking data storage unit that stores the light-blocking data of the pixel data in units of pixels. And a pixel defect correction unit.

In order to achieve the above-mentioned object, a second image pickup device according to the present invention has a MOS type solid-state image pickup device in which photodiodes are arranged two-dimensionally, and a solid-state image pickup device is opened and closed by a shutter operation. The light shielding part that conducts / shields the incident light and the charges accumulated in the photodiode of the solid-state image sensor are reset at the end of all addresses, and then the signal charges accumulated in the photodiode are read out first. During at least a part of the period, the signal charge accumulated in the exposure state in which the shutter of the light shielding unit is opened is converted into the first image data from the analog image signal output from the solid-state image sensor as current or voltage. Then, the charges accumulated in the photodiode of the solid-state image sensor are reset at the end of all addresses, and then accumulated in the photodiode. In the first period of reading the stored signal charges, the signal charges accumulated in the closed state where the shutter of the light shielding unit is closed are output as current or voltage from the solid-state image sensor, and the analog light-shielding signal is used as the first light-shielding data. A / D conversion unit for converting, first imaging data, and first imaging data
Defective pixel position storage unit that stores n (n is a natural number) two-dimensional pixel defect position data existing in the light-shielding data, and at least a part of the pixel defect position data stored in the defective pixel position storage unit A first pixel defect correction unit that performs a correction process on the first image pickup data and the light shielding data based on the pixel defect position data to obtain second image pickup data and second light shielding data, respectively. An image data storage unit that stores the second image data from the first pixel defect correction unit in pixel units; and a light-shield data storage unit that stores the second light-shield data from the first pixel defect correction unit in pixel units. And a second pixel defect correction unit that subtracts, for each pixel, the second light-shielding data read from the light-shielding data storage unit from the second image-capturing data read from the image-capturing data storage unit.

In the first and second image pickup devices, the first
It is preferable that the pixel defect correction unit of No. 1 performs the correction process based on a maximum of n pixel defect position data from a pixel defect position data stored in the defective pixel position storage unit having a large pixel defect level.

According to the above arrangement, even if there is data having a large white defect component with respect to the dynamic range, it is possible to correct the white defect until sufficient image quality is maintained.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration example of a solid-state image pickup device according to an embodiment of the present invention. In FIG. 1, 101 is a light shielding device (light shielding unit), 102 is a shutter control device, 103 is a solid-state image sensor, 104 is a timing generator, 105 is an A / D converter, and 106 is a first pixel address registration method. White flaw correction device (1st
Pixel defect correction unit), 107 is a white defect pixel position storage device (defective pixel position storage unit), and 108 is an imaging data storage device (imaging data storage) that stores the imaging data output from the first white defect correction device 106. Part), 109 is a shading data storage device (shading data storage part) for storing shading data output from the first white defect correction device 106, and 110 is a second white defect correction device (second pixel) based on a data difference. Defect correction unit).

2 and 3 show the operating state (open / closed state) of the light shielding device 101 of FIG. 1 when a CCD and a MOS type solid-state image sensor are used as the solid-state image sensor, and the solid-state image sensor of FIG. 1, respectively. FIG. 3 is a diagram showing the timing of drive pulses to 103. 2 and 3, O
C is the open / closed state of the light shielding device, CD is the charge sweep pulse,
CR indicates a charge read pulse and VS indicates a vertical synchronizing signal. Further, in FIG. 3, Pa represents the position of the charge sweep pulse CD of the last address in all addresses, and Pb represents the position of the charge read pulse CR of the last address in all addresses.

FIG. 4 is a diagram schematically showing the principle of the present invention. 4A is an image diagram of image pickup data before correction processing by the first white defect correction device 106, and FIG. 4B is an image diagram of light shielding data before correction process by the first white defect correction device 106. (C) is the first white defect correction device 1
FIG. 4 is an image diagram of the image pickup data after the correction processing according to 06.
FIG. 4D is an image diagram of the light shielding data after the correction process by the first white defect correction device 106, and FIG. 4E is an image diagram after the correction process by the second white defect correction device 110.

Hereinafter, CCD and M will be used as solid-state image pickup devices.
The operation of the solid-state imaging device according to the present embodiment when the OS type solid-state imaging device is used will be described.

First, the operation when the CCD solid-state image pickup device is used will be described with reference to FIGS. 1, 2 and 4.

The timing generator 104 includes a photoelectric conversion unit that converts an optical image of a subject into charge information, a charge transfer unit that transfers the photoelectrically converted signal charges, and a charge detection unit that detects the transferred signal charges. In order to read the charge accumulated in the photoelectric conversion unit from the photoelectric conversion unit to the charge transfer unit, and the charge sweep pulse CD (FIG. 2) for resetting the charge accumulated in the photoelectric conversion unit in the solid-state imaging device 103 having And a charge read pulse CR (FIG. 2) are applied.

First, in the exposure state in which the light shielding device 101 is opened during a part of the period T of the charge read pulse CR from the last pulse of the charge sweep pulse CD, the solid-state image sensor 103 outputs the A / D conversion signal. The imaging data (FIG. 4 (a)) converted into a digital value by the device 5, and subsequently, from the last pulse of the charge sweep pulse CD, which is the same time as before, in the light-shielding state in which the light shielding device 101 is closed. During the period T of the charge read pulse CR, the solid-state image sensor 103
The light-shielding data (FIG. 4B) output from the A / D converter 5 and converted into a digital value by the A / D converter 5 is obtained.

At this time, the means for resetting the charge accumulated in the photoelectric conversion portion can be replaced with the last charge read pulse before the application of the charge read pulse CR. These imaging data (FIG. 4A) and light-shielding data (FIG. 4)
In (b), the correction processing is performed by the first white defect correction device 106 based on the pixel position data of the white defect from the white defect pixel position storage device 107. At this time, the first white defect correction device 106 performs correction processing based on pixel position data having a large white defect level and pixel position data corresponding to the maximum memory capacity of the white defect pixel position storage device 107.
The corrected image pickup data (FIG. 4C) is stored in the image pickup data storage device 108 in units of pixels, and the corrected light shield data (FIG. 4D) is shown in units of pixels. It is stored in the shading data storage device 109.

The two types of the image pickup data (FIG. 4 (c)) and the light-shielding data (FIG. 4 (d)) thus stored are differentiated by the second white defect correction device 110 on a pixel-by-pixel basis.
From the image pickup signal and the white flaw signal in the image pickup data (FIG. 4C), only the white flaw signal in the light-shielding data (FIG. 4D) is subtracted to obtain the white flaw corrected image (FIG. 4E). Is obtained.

Next, the operation when the MOS type solid-state image pickup device is used will be described with reference to FIGS. 1, 3 and 4.

The timing generator 104 is stored in the photoelectric conversion unit in the solid-state image pickup device 103 having a photoelectric conversion unit for converting an optical image of a subject into charge information and a charge detection unit for detecting photoelectrically converted signal charges. Charge sweep pulse CD for resetting the charge for each address in order
(FIG. 3) and a charge read pulse CR (FIG. 3) for sequentially reading the charges accumulated in the photoelectric conversion unit from the photoelectric conversion unit to the charge detection unit for each address.

First, in the exposure state in which the light shielding device 101 is opened for a partial period within the period T of the first charge read pulse CR that follows from the last pulse of all addresses of the charge sweep pulse CD, the solid-state image sensor 103 is opened. Output from A
The imaging data (FIG. 4A) converted into a digital value by the / D converter 5, and subsequently, the light shielding device 101.
In the light-shielding state in which the solid-state image sensor 10 is closed, the solid-state imaging device 10 is in the period T of the first charge read pulse CR that comes from the last pulse of all addresses of the charge sweep pulse CD, which is the same time as before.
The light-shielding data (FIG. 4B) output from the A / D converter 3 and converted into a digital value by the A / D converter 5 is obtained.

At this time, the means for sequentially resetting the charges accumulated in the photoelectric conversion unit for each address can be substituted by the charge read pulse of each last address before the charge read pulse CR is applied. The image pickup data (FIG. 4A) and the light-shielding data (FIG. 4B) are the first white defect correction device based on the white defect pixel position data from the white defect pixel position storage device 107. At 106, correction processing is performed. At this time, the first white defect correction device 106
Performs the correction processing based on the pixel position data having the largest white defect level and the pixel position data corresponding to the maximum memory capacity of the white defect pixel position storage device 107. The corrected image pickup data (FIG. 4C) is stored in the image pickup data storage device 108 in units of pixels, and the corrected light shield data (FIG. 4D) is shown in units of pixels. It is stored in the shading data storage device 109.

The two types of the image pickup data (FIG. 4C) and the light-shielding data (FIG. 4D) stored in the second white defect correction device 110 are differentiated in pixel units,
From the image pickup signal and the white flaw signal in the image pickup data (FIG. 4C), only the white flaw signal in the light-shielding data (FIG. 4D) is subtracted to obtain the white flaw corrected image (FIG. 4E). Is obtained.

In the above embodiment, the light-shielding data is read once in the present embodiment, but it may be read a plurality of times and the average thereof may be used in order to improve the accuracy. Absent.

[0026]

As described above, according to the present invention,
Even when there is data having a large white defect component with respect to the dynamic range, it is possible to correct the white defect until the image quality of the white defect corrected image is sufficiently maintained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of an image pickup apparatus according to an embodiment of the present invention.

2 is an operation state of a light shielding means 101 of FIG. 1 and a solid-state image sensor 103 of FIG. 1 when a CCD solid-state image sensor is used.
Of the drive pulse timing

FIG. 3 is a diagram when a MOS type solid-state imaging device is used.
Of the light shielding means 101 and the solid-state image sensor 1 of FIG.
Diagram showing the timing of the drive pulse of 03.

FIG. 4 is a diagram schematically showing the principle of the present invention.

[Explanation of symbols]

Reference Signs List 101 light shielding device 102 shutter control device 103 solid-state image sensor 104 timing generator 105 A / D converter 106 first white defect correction device (first pixel defect correction unit) by a pixel address registration method 107 white defect pixel position storage device (Defective pixel position storage unit) 108 Imaging data storage device (imaging data storage unit) 109 Shading data storage device (Shading data storage unit) 110 Second white defect correction device based on data difference (second
Pixel defect correction unit)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinichi Tashiro             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 4M118 AA05 AB01 BA08 BA14 CA02                       FA06                 5C024 AX01 CX23 CX43 GX03 GY01                       GY31 HX23 HX29

Claims (3)

[Claims] 1. A solid-state imaging device using a CCD, in which photodiodes are arranged two-dimensionally, a light shielding section for conducting / blocking incident light to / from the solid-state imaging device by opening / closing a shutter, and the solid-state imaging device. After resetting the electric charge accumulated in the photodiode of the device, the shutter of the light shielding unit is brought into an exposure state in at least a part of a period of reading the signal electric charge accumulated in the photodiode. The analog image pickup signal in which the signal charge accumulated as a current or voltage is output from the solid-state image pickup device as a first
Of the solid-state image sensor, the charge accumulated in the photodiode of the solid-state image sensor is reset, and then the signal charge accumulated in the photodiode is read out during the period in which the light shield unit is read. An A / D conversion unit that converts an analog light-shielding signal, in which a signal charge accumulated in a shielded state with a shutter closed and output as a current or a voltage from the solid-state image sensor, into first light-shielding data; Defective pixel position storage unit that stores n (n is a natural number) two-dimensional pixel defect position data existing in the data and the first light-shielding data; and the pixel defect stored in the defective pixel position storage unit. A correction process is performed on the first imaging data and the light-shielding data based on pixel defect position data of at least a part of the position data, and A first pixel defect correction unit that obtains second image pickup data and second light shielding data; an image pickup data storage unit that stores the second image pickup data from the first pixel defect correction unit in pixel units; A light-shielding data storage unit that stores the second light-shielding data from the first pixel defect correction unit on a pixel-by-pixel basis, and read from the light-shielding data storage unit from the second image-capturing data read from the image-capturing data storage unit An image pickup apparatus comprising: a second pixel defect correction unit that subtracts the second light-shielding data on a pixel-by-pixel basis. 2. A MOS type solid-state image pickup device in which photodiodes are arranged two-dimensionally, a light shielding section for conducting / shielding incident light to / from the solid-state image pickup device by opening / closing a shutter, and the solid-state image pickup device. After resetting the charge stored in the photodiode of the device at the end of all addresses, and then at least a part of the period in which the signal charge stored in the photodiode is first read out, the light shielding is performed. Signal charges accumulated in the exposure state in which the shutter is opened are converted into first imaging data from an analog imaging signal output as a current or a voltage from the solid-state imaging device, and subsequently, the solid-state imaging device. Reset the charge stored in the photodiode at the end of all addresses, and then reset the signal charge stored in the photodiode. In the first reading period, the signal light accumulated in the closed state where the shutter of the light blocking unit is closed is converted into the first light blocking data from the analog light blocking signal output as the current or the voltage from the solid-state imaging device. A / D
A conversion unit; a defective pixel position storage unit that stores n (n is a natural number) two-dimensional pixel defect position data existing in the first imaging data and the first light shielding data; Correction processing is performed on the first imaging data and the light-shielding data based on at least a part of the pixel defect position data stored in the storage unit, and the second imaging data and A first pixel defect correction unit that obtains second light-shielding data; an imaging data storage unit that stores the second imaging data from the first pixel defect correction unit in pixel units; and the first pixel defect A shading data storage unit that stores the second shading data from the correction unit in pixel units, and a second shading data storage unit that reads the second shading data storage unit read from the shading data storage unit Imaging device for the second pixel defect correction section for subtracting the second light-shielding data in pixel units comprising the. 3. The first pixel defect correction unit is based on a maximum of n pixel defect position data from a pixel defect level having a large pixel defect level among the pixel defect position data stored in the defective pixel position storage unit. The image pickup apparatus according to claim 1 or 2, wherein correction processing is performed by using the image pickup apparatus.