Image pickup apparatus equipped with function of detecting image shaking

• US 20080284858A1
• Filed: 05/07/2008
• Published: 11/20/2008
• Est. Priority Date: 05/18/2007
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Sasaki, Masaaki, Matsui, Shinichi
• Granted Patent: US 8,564,674 B2
• Time in Patent Office: Days
• US Class Current: 348/208.1
• CPC Class Codes: H04N 23/673 based on contrast or high frequency components of image signals, e.g. hill climbing method
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 5/144 Movement detection for video coding H04N19/503; analysis of motion in general G06T7/20
• CPC Class Codes: H04N 5/145 Movement estimation for video coding H04N19/51

Abstract

In an initial stage, using a global motion vector, a rough degree of image shaking is determined. After the image shaking is determined to have converged to some measure, using the difference values between frames, the finer degree of the image shaking is determined. And if it is determined to be free of image shaking, the recording photography is made to be done. Thereby, with certainty in the timing of no hand shaking and no image shaking, the photographing can be done.

Claims

1. An image pickup apparatus equipped with a function of detecting image shaking, comprising:

a first image shaking detection means for detecting image shaking;

a second image shaking detection means for detecting image shaking by a method different from the first image shaking detection means; and

a determination means for determining that image shaking has disappeared, when, after image shaking detected by the first image shaking detection means is determined to have converged, further, image shaking detected by the second image shaking detection means is determined to have converged.

2. An image pickup apparatus according to claim 1,

wherein the second image shaking detection means starts detection processing of image shaking by a method different from the first image shaking detection means after image shaking detected by the first image shaking detection means is determined to have converged.

3. An image pickup apparatus according to claim 1,

wherein the determination means does not determine that image shaking has disappeared before a stage in which image shaking detected by the first image shaking detection means is determined to have converged, even if the state is that image shaking detected by the second image shaking detection means is determined to have converged.

4. An image pickup apparatus according to claim 1,

wherein when image shaking is determined to have disappeared by the determination means, photographic recording is automatically carried out.

5. An image pickup apparatus according to claim 1,

wherein during a time when image shaking is determined to be present by the determination means, photographic recording is inhibited or warned against by alarm at a time of instruction to photograph.

6. An image pickup apparatus according to claim 1,

wherein detection accuracy of image shaking of the second image shaking detection means is higher than that of the first image shaking means.

7. An image pickup apparatus according to claim 1,

wherein detection accuracy of image shaking of the second image shaking detection means deteriorates while being not focused on a subject, and a degree of deterioration of that accuracy is greater than a deterioration of accuracy of the first image shaking detection means while being not focused on the subject.

8. An image pickup apparatus according to claim 1,

wherein a detection accuracy of the second image shaking detection means deteriorates while motion of a subject or the image pickup apparatus is large, and a degree of deterioration of the accuracy is greater than a deterioration of accuracy of the first image shaking detection means while motion of a subject or of the image pickup apparatus is large.

9. An image pickup apparatus according to claim 1,

wherein the first image shaking detection means detects a component of image shaking caused by hand shaking among a component of image shaking caused by hand shaking and a component of image shaking caused by the motion of a subject, and

the second image shaking detection means detects image shaking irrespective of a component of image shaking caused by hand shaking and a component of image shaking caused by motion of a subject.

10. An image pickup apparatus according to claim 1,

wherein the first image shaking detection means detects image shaking by a motion vector detected from a plurality of image frames successively obtained.

11. An image pickup apparatus according to claim 10,

wherein the motion vector is a motion vector of whole images obtained by photographing.

12. An image pickup apparatus according to claim 1,

wherein the second image shaking detection means detects image shaking according to a difference value between two successive image frames.

13. An image pickup apparatus according to claim 12,

wherein the second image shaking detection means detects image shaking according to a difference value comparing image data of each frame by every pixel.

14. An image pickup apparatus according to claim 12,

wherein the determination means holds a minimum difference value among the difference values successively detected by the second image shaking detection means, and determines whether image shaking is present or not according to whether the newly detected difference value has become lower than the held difference value or not.

15. An image pickup apparatus according to claim 14,

wherein the determination means updates the held difference value with the newly detected difference value when the newly detected difference value becomes lower than the held difference value, and determines that image shaking has disappeared when the number of times of the update becomes more than a predetermined number of times.

16. An image pickup apparatus according to claim 12, further comprising a high frequency component detection means for detecting a high frequency component in an image frame,

wherein the determination means determines whether a high frequency component detected by the high frequency component detection means is lower than a reference value or not, and determines whether image shaking is present or not according to a difference value detected by the second image shaking detection means, excluding from an object of evaluation an image frame in which a high frequency component is determined to be lower than the reference value.

17. An image pickup apparatus according to claim 15, further comprising a high frequency component detection means for detecting a high frequency component in an image frame,

wherein the determination means does not update the held difference value with a difference value detected based on an image frame in which a high frequency component detected by the high frequency component detection means is lower than the reference value, even if the difference value is lower than the held difference value.

18. An image pickup apparatus according to claim 12,

wherein the determination means sets a difference value between the initial successive two image frames as a reference value, and subsequently, when a difference value between newly calculated image frames is lower than the reference value, the reference value is updated with the difference value between the newly calculated image frames, and determines that image shaking has become less, when the number of times of update has become greater than a predetermined number of times.

19. An image pickup apparatus equipped with a function of detecting image shaking, comprising:

a difference value calculation means for calculating a difference value between two successive image frames;

a high frequency component detection means for detecting a high frequency component in an image frame; and

a determination means for determining whether image shaking is present or not according to a difference value calculated by the difference value calculation means, excluding image frames in which the high frequency component is lower than a reference value from an object of evaluation.

20. An image pickup apparatus equipped with a function of detecting image shaking, comprising:

a difference value calculation means for calculating a difference value between two successive image frames;

a holding means for holding a minimum difference value among the difference values successively detected by the difference value calculation means; and

a determination means for updating the held difference value with a new difference value calculated by the difference value calculation means corresponding to a new frame when the new difference value is lower than the held difference value held by the holding means, and determining that image shaking has disappeared when the number of times of update has become greater than a predetermined number of times.

21. A method for controlling an image pickup apparatus equipped with a function of detecting image shaking, including:

a first image shaking detection step of detecting image shaking;

a second image shaking detection step of detecting image shaking by a method different from the first image shaking detection step;

and a determination step of determining that image shaking has disappeared, when, after image shaking detected in the first image shaking detection step is determined to have converged, further, image shaking detected in the second image shaking detection step is determined to have converged.

22. A method for controlling an image pickup apparatus equipped with a function of detecting image shaking, including:

a difference value calculation step of calculating a difference value between two successive image frames;

a high frequency component detection step of detecting a high frequency component in an image frame; and

a determination step of determining whether image shaking is present or not according to a difference value calculated in the difference value calculation step, excluding image frames in which the high frequency component is lower than a reference value from an object of evaluation.

23. A method for controlling an image pickup apparatus equipped with a function of image shaking, including:

a difference value calculation step of calculating a difference value between two successive image frames;

a holding step of holding a minimum difference value among the difference values successively detected in the difference value calculation step; and

a determination step of updating the held difference value with a new difference value calculated in the difference value calculation step corresponding to a new frame when the new difference value is lower than the held difference value held in the holding step, and

determining that image shaking has disappeared when the number of times of update has become greater than a predetermined number of times.