IMAGE CAPTURING APPARATUS, IMAGE CAPTURING METHOD, AND STORAGE MEDIUM

• US 20100321525A1
• Filed: 05/19/2010
• Published: 12/23/2010
• Est. Priority Date: 06/17/2009
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Nagata, Toru
• Granted Patent: US 8,314,852 B2
• Time in Patent Office: Days
• US Class Current: 348/230.1
• CPC Class Codes: H04N 23/62 Control of parameters via user interfaces
• CPC Class Codes: H04N 23/631 Graphical user interfaces [GUI] specially adapted for controlling image capture or setting capture parameters
• CPC Class Codes: H04N 23/635 Region indicators; Field of view indicators
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof
• CPC Class Codes: H04N 25/533 by using differing integration times for different sensor regions

Abstract

The present invention provides an image capturing apparatus comprising an image capturing unit configured to capture an image; a generation unit configured to generate an exposure period map by assigning, to each of the plurality of image sensor pixels, exposure control information to control a charge accumulation time, based on preliminary capturing data obtained by preliminary capturing using the image capturing unit, the exposure control information including first exposure control information corresponding to a first accumulation time and second exposure control information corresponding to an accumulation time longer than the first exposure control information; a correction unit configured to expand a first region having the first exposure control information on the exposure period map; and a control unit configured to control the accumulation time for each of the plurality of image sensor pixels in accordance with the exposure period map corrected by the correction unit.

Claims

1. An image capturing apparatus comprising:

an image capturing unit configured to capture an image by driving a plurality of image sensor pixels;

a generation unit configured to generate an exposure period map by assigning, to each of the plurality of image sensor pixels, exposure control information to control a charge accumulation time, based on preliminary capturing data obtained by preliminary capturing using said image capturing unit, the exposure control information including first exposure control information corresponding to a first accumulation time and second exposure control information corresponding to an accumulation time longer than the first exposure control information;

a correction unit configured to expand a first region having the first exposure control information on the exposure period map; and

a control unit configured to control the accumulation time for each of the plurality of image sensor pixels in accordance with the exposure period map corrected by said correction unit,

wherein said image capturing unit performs main capturing in accordance with the accumulation time controlled by said control unit.

2. The apparatus according to claim 1, wherein said image capturing unit is configured to perform the preliminary capturing with uniform accumulation time for each pixel of the image sensor.

3. The apparatus according to claim 1, further comprising a boundary luminance configuration unit configured to set a boundary luminance representing a boundary of the first region,

wherein said generation unit is configured to assign one of the first exposure control information and the second exposure control information to each pixel of the image sensor by binarizing a luminance of each pixel in the preliminary capturing data using the boundary luminance as a threshold.

4. The apparatus according to claim 1, further comprising a gain correction unit configured to perform gain correction for main capturing data obtained by the main capturing based on the accumulation time.

5. The apparatus according to claim 1, wherein said image capturing unit is configured to perform another preliminary capturing with another capturing condition when the preliminary capturing data includes a pixel having a luminance more than a predetermined value.

6. The apparatus according to claim 1, wherein the image sensor is a CMOS sensor.

7. The apparatus according to claim 6, wherein said image capturing unit is configured to generate a reset pulse, a row transfer pulse, and a column transfer pulse as driving pulses for each pixel of the image sensor, and provide each pixel in one row within the image sensor with column transfer timings using the column transfer pulse, when performing the main capturing, wherein the column transfer timings correspond to one of the first control information and the second control information.

8. The apparatus according to claim 6, wherein said image capturing unit is configured to generate a reset pulse, a row transfer pulse, and a column transfer pulse as driving pulses for each pixel of the image sensor, and provides each pixel in one row within the image sensor with a reset timing corresponding to the second control information using the reset pulse and the row transfer pulse, and a reset timing corresponding to the first control information using the reset pulse and the column transfer pulse, when performing the main capturing.

9. The apparatus according to claim 6, wherein said image capturing unit is configured to generate a row reset pulse, a column reset pulse, and a row transfer pulse as driving pulses for each pixel of the image sensor, and provides each pixel in one row within the image sensor with a reset timing corresponding to the second control information using the row reset pulse and the row transfer pulse, and a reset timing corresponding to the first control information using the column reset pulse and the row transfer pulse, when performing the main capturing.

11. A computer-readable storage medium storing a program which controls a computer apparatus and causes the computer apparatus to function as each unit of an image capturing apparatus of claim 1.

10. A method of capturing an image performed by a image capturing apparatus, comprising:

a preliminary capturing step of capturing an image by driving a plurality of image sensor pixels;

a generation step of generating an exposure period map by assigning, to each of the plurality of image sensor pixels, exposure control information to control a charge accumulation time, based on preliminary capturing data obtained by preliminary capturing in said image capturing step, the exposure control information including first exposure control information corresponding to a first accumulation time and second exposure control information corresponding to an accumulation time longer than the first exposure control information;

a correction step of expanding a first region having the first exposure control information on the exposure period map;

a control step of controlling the accumulation time for each of the plurality of image sensor pixels in accordance with the exposure period map corrected in the correction step; and

a main capturing step of capturing an image in accordance with the accumulation time controlled in the control step.