Solid-state image sensor, image pickup apparatus, and correcting method

Patent metadata

Field	Value
Publication number	US-9749559-B2
Application number	US-201414340330-A
Country	US
Kind code	B2
Filing date	Jul 24, 2014
Priority date	Jul 31, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

Provided is a solid-state image sensor, including: a pixel unit including a valid pixel area and an optical-black pixel area; a plurality of reading units configured to read pixel values of a large number of pixels of the pixel unit line by line; a plurality of correction data generating units corresponding to the plurality of reading units, respectively, each of the plurality of correction data generating units being configured to generate correction data based on pixel values read from the optical-black pixel area out of the pixel values read from the pixel unit by the corresponding reading unit line by line; and a correcting unit configured to correct pixel values read from the valid pixel area out of the pixel values read from the pixel unit by the reading unit line by line based on the correction data generated by the corresponding correction data generating unit.

First claim

What is claimed is:

1. An image sensor, comprising:
a pixel unit including a valid pixel area and a plurality of optical-black pixel areas;
a plurality of A/D converters configured to read pixel values of a large number of pixels of the pixel unit line by line;
a logical block, including:
a plurality of digital correction data generators corresponding to the plurality of A/D converters, respectively, wherein one digital correction data generator is provided for each of the A/D converters in the plurality of A/D converters, wherein each digital correction data generator in the plurality of digital correction data generators is operable to generate correction data based on pixel values read from the optical-black pixel areas out of the pixel values read from the pixel unit by the corresponding A/D converter line by line;
a single difference calculator, wherein the single difference calculator is operable to receive at least first, second, third, and fourth inputs, wherein the first input includes pixel values from a first one of the A/D converters included in the plurality of A/D converters, wherein the second input includes pixel values from a second one of the A/D converters included in the plurality of A/D converters, wherein the third input includes correction data generated by a first one of the correction data generators included in the plurality of correction data generators, wherein the fourth input includes correction data generated by a second one of the correction data generators included in the plurality of correction data generators, wherein each of the digital correction data generators is configured to obtain an average of pixel values of all colors read from the optical-black pixel areas out of the pixel values read from the pixel unit by the A/D converters line by line to thereby generate a streak correction amount, wherein each of the digital correction data generators is configured to obtain, for each of the colors, an average of pixel values of each color read from the optical-black pixel area out of the pixel value read from the pixel unit by the A/D convertors line by line to thereby generate color-step correction amounts, wherein a difference between the streak correction amount for a selected line and the color-step correction amount generated for each color read from the optical-black pixel area for the selected line is calculated, wherein the calculated difference is added to pixel values of pixels in the selected line of pixels in the valid pixel area for the corresponding color to obtain color corrected output values; and
a single offset adder, wherein the single offset adder is operable to receive the color corrected output values from the single output of the single difference calculator, wherein the single offset adder is operable to add a predetermined offset value to the color corrected output values, and wherein the single offset adder is operable to output color-step-corrected sensor output values.

2. The image sensor according to claim 1 , wherein the plurality of A/D converters includes a first A/D converter and a second A/D converter, wherein the first A/D converter reads pixel values from each line in an upper half of the lines of the pixel unit, and wherein the second A/D converter reads pixel values from each line in a lower half of the lines of the pixel unit.

3. The image sensor according to claim 1 , wherein the plurality of optical-black pixel areas includes a first optical-black pixel area and a second optical black pixel area, wherein the first optical-black pixel area corresponds to a first end of each of the lines of pixels in the pixel unit, and wherein the second optical-black pixel area corresponds to a second end of each of the lines of pixels in the pixel unit.

4. An image pickup apparatus, comprising:
an image sensor including
a pixel unit including a valid pixel area and a plurality of optical-black pixel areas,
a plurality of A/D converters configured to read pixel values of a large number of pixels of the pixel unit line by line,
a logical block, including:
a plurality of correction data generators corresponding to the plurality of A/D converters, respectively, wherein one correction data generator is provided for each of the A/D converters in the plurality of A/D converters, wherein each of the plurality of correction data generators generates correction data based on pixel values read from the optical-black pixel areas out of the pixel values read from the pixel unit by the A/D converters line by line, wherein each of the digital correction data generators is configured to obtain an average of pixel values of all colors read from the optical-black pixel areas out of the pixel values read from the pixel unit by the A/D converters line by line to thereby generate a streak correction amount, wherein each of the digital correction data generators is configured to obtain, for each of the colors, an average of pixel values of each color read from the optical-black pixel area out of the pixel value read from the pixel unit by the A/D converters line by line to thereby generate color-step correction amounts;
a single difference calculator, wherein the single difference calculator is operable to receive at least first, second, third, and fourth inputs, wherein the first input includes pixel values from a first one of the A/D converters, the second input includes pixel values from a second one of the A/D converters included in the plurality of A/D converters, the third input includes correction data generated by a first one of the correction data generators included in the plurality of correction data generators, and the fourth input includes correction data generated by a second one of the correction data generators included in the plurality of correction data generators, wherein a difference between the streak correction amount for a selected line and the color-step correction amount generated for each color read from the optical-black pixel area for the selected line is calculated, wherein the calculated difference is added to pixel values of pixels in the selected line of pixels in the valid pixel area for the corresponding color to obtain color corrected output values; and
an offset adder, wherein the offset adder receives the color corrected output values, wherein the offset adder is operable to add a predetermined offset value to the color corrected output values, and wherein the offset adder outputs color-step-corrected sensor output values.

5. A correcting method employed by an image sensor including a pixel unit including a valid pixel area and a plurality of optical-black pixel areas, and a plurality of A/D converters configured to read pixel values of a large number of pixels of the pixel unit line by line, the correcting method comprising:
generating first streak correction data based on pixel values read from at least some of the plurality of optical-black pixel areas by a first one of the A/D converters included in the plurality of A/D converters, wherein a first streak correction amount is calculated, and wherein the first streak correction amount is an average of the pixel values in a first line of pixels in the optical-black pixel areas;
generating color-step correction amounts based on pixel values read from the at least some of the plurality of optical black pixel areas by the first one of the A/D converters, wherein a first color-step correction amount is calculated for a first plurality of pixel of a first color that are included in the first line of pixels in the optical-black pixel areas, and wherein the first color-step correction amount for the first color is an average of pixel values of pixels in the first line of pixels in the optical-black pixel areas having the first color;
calculating a difference between the first streak correction amount

Assignees

• Sony Corp

Inventors

• Tanaka Hiromichi

Classifications

• H04N25/633 Primary

  by using optical black pixels · CPC title

• H04N5/361 Primary

  Electricity · mapped topic

• H04N5/2176

  Electricity · mapped topic