IMAGE CAPTURING APPARATUS, CONTROL METHOD THEREFOR, AND PROGRAM

• US 20090153680A1
• Filed: 11/10/2008
• Published: 06/18/2009
• Est. Priority Date: 12/13/2007
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Shibata, Masahiro
• Granted Patent: US 8,319,842 B2
• Time in Patent Office: Days
• US Class Current: 348/208.600
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6845 by combination of a plurality of images sequentially taken
• CPC Class Codes: H04N 5/144 Movement detection for video coding H04N19/503; analysis of motion in general G06T7/20

Abstract

An image capturing apparatus includes a motion vector detection unit which detects a motion vector on the basis of the correlation between image signals continuously captured by an image capturing unit, a reliability evaluation value calculation unit which calculates the reliability evaluation value of the motion vector detected by the motion vector detection unit, a blurring correction amount determination unit which determines the image blurring correction amount on the basis of the motion vector detected by the motion vector detection unit, a correction amount reduction unit which reduces the image blurring correction amount on the basis of the reliability evaluation value calculated by the reliability evaluation value calculation unit, and a blurring correction unit which corrects image blurring on the basis of the image blurring correction amount reduced by the correction amount reduction unit.

Claims

1. An image capturing apparatus comprising:

an image capturing unit which captures an object image formed by an imaging optical system and outputs an image signal;

a motion vector detection unit which detects a motion vector on the basis of correlation between image signals continuously captured by said image capturing unit;

a reliability evaluation value calculation unit which calculates a reliability evaluation value of the motion vector detected by said motion vector detection unit;

a blurring correction amount determination unit which determines an image blurring correction amount on the basis of the motion vector detected by said motion vector detection unit;

a correction amount reduction unit which reduces the image blurring correction amount in accordance with a reduction rate determined based on the reliability evaluation value calculated by said reliability evaluation value calculation unit; and

a blurring correction unit which corrects image blurring on the basis of the image blurring correction amount reduced by said correction amount reduction unit.

3. The apparatus according to claim 1, wherein a frame of said image capturing unit is divided into a plurality of blocks, said motion vector detection unit detects a motion vector of each divided block, and said reliability evaluation value calculation unit calculates, as the reliability evaluation value of the motion vector, a ratio of motion vectors determined to be valid to motion vectors of all blocks that are detected by said motion vector detection unit.

5. The apparatus according to claim 1, wherein said correction amount reduction unit decreases reduction of the image blurring correction amount as the reliability evaluation value is larger.

2. An image capturing apparatus comprising:

an image capturing unit which captures an object image formed by an imaging optical system capable of zooming, and outputs an image signal;

a motion vector detection unit which detects a motion vector on the basis of correlation between image signals continuously captured by said image capturing unit;

a reliability evaluation value calculation unit which calculates a reliability evaluation value of the motion vector detected by said motion vector detection unit;

a blurring correction amount determination unit which determines an image blurring correction amount on the basis of the motion vector detected by said motion vector detection unit;

a correction amount reduction unit which reduces the image blurring correction amount in accordance with a reduction rate determined based on the reliability evaluation value calculated by said reliability evaluation value calculation unit and a zoom position of the imaging optical system; and

a blurring correction unit which corrects image blurring on the basis of the image blurring correction amount reduced by said correction amount reduction unit.

4. The apparatus according to claim 2, wherein a frame of said image capturing unit is divided into a plurality of blocks, said motion vector detection unit detects a motion vector of each divided block, and said reliability evaluation value calculation unit calculates, as the reliability evaluation value of the motion vector, a ratio of motion vectors determined to be valid to motion vectors of all blocks that are detected by said motion vector detection unit.

6. The apparatus according to claim 2, wherein said correction amount reduction unit decreases reduction of the image blurring correction amount as the reliability evaluation value is larger.

7. The apparatus according to claim 2, wherein when the reliability evaluation value remains unchanged, said correction amount reduction unit increases reduction of the image blurring correction amount as the zoom position of the imaging optical system comes close to a telephoto end.

8. A method of controlling an image capturing apparatus having an image capturing unit which captures an object image formed by an imaging optical system and outputs an image signal, the method comprising:

a motion vector detection step of detecting a motion vector on the basis of correlation between image signals continuously captured by the image capturing unit;

a reliability evaluation value calculation step of calculating a reliability evaluation value of the motion vector detected in the motion vector detection step;

a blurring correction amount determination step of determining an image blurring correction amount on the basis of the motion vector detected in the motion vector detection step;

a correction amount reduction step of reducing the image blurring correction amount in accordance with a reduction rate determined based on the reliability evaluation value calculated in the reliability evaluation value calculation step; and

a blurring correction step of correcting image blurring on the basis of the image blurring correction amount reduced in the correction amount reduction step.

10. A program which causes a computer to execute a control method defined in claim 8.

9. A method of controlling an image capturing apparatus having an image capturing unit which captures an object image formed by an imaging optical system capable of zooming, and outputs an image signal, the method comprising:

a motion vector detection step of detecting a motion vector on the basis of correlation between image signals continuously captured by the image capturing unit;

a reliability evaluation value calculation step of calculating a reliability evaluation value of the motion vector detected in the motion vector detection step;

a blurring correction amount determination step of determining an image blurring correction amount on the basis of the motion vector detected in the motion vector detection step;

a correction amount reduction step of reducing the image blurring correction amount in accordance with a reduction rate determined based on the reliability evaluation value calculated in the reliability evaluation value calculation step and a zoom position of the imaging optical system; and

a blurring correction step of correcting image blurring on the basis of the image blurring correction amount reduced in the correction amount reduction step.

11. A program which causes a computer to execute a control method defined in claim 9.