Image stabilization apparatus, control method therefor, storage medium storing control program therefor, and image pickup apparatus equipped with image stabilization apparatus

• US 9,253,403 B2
• Filed: 08/05/2014
• Issued: 02/02/2016
• Est. Priority Date: 08/07/2013
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Noguchi, Masaaki
• Primary Examiner(s): OSINSKI, MICHAEL S
• Application Number:
  US14/451,494
• Publication Number:
  US 20150042827A1
• Time in Patent Office: 546 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G03B 2205/0015 by displacing one or more optical elements normal to the optical axis
• CPC Class Codes: H04N 23/667 Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 23/687 by shifting the lens or sensor position

Abstract

An image stabilization (IS) apparatus that is capable of preventing change of a field angle due to unnecessary mode transition. A selection unit transfers from a first IS mode to a second IS mode with a larger IS effect when a detected shake amount is maintained below a first threshold beyond first determination time and the shake amount is not maintained below a second threshold that is lower than the first threshold beyond a third determination time that is shorter than a second determination time, and transfers from the first IS mode to a third IS mode with the smallest IS effect when the shake amount is maintained below the second threshold beyond the second determination time that is shorter than the first determination time. A control unit controls an IS unit that corrects an image blur using the shake amount in the selected IS mode.

Claims

1. An image stabilization apparatus comprising:

a shake detection unit configured to detect a shake amount of an image pickup apparatus;

an image stabilization unit configured to correct an image blur using an output signal outputted from said shake detection unit;

a selection unit configured to select one image stabilization mode from among at least three image stabilization modes including a first image stabilization mode, a second image stabilization mode, and a third image stabilization mode; and

a control unit configured to control said image stabilization unit according to the image stabilization mode selected by said selection unit,

wherein an image stabilization effect of the second image stabilization mode is larger than an image stabilization effect of the first image stabilization mode, and the image stabilization effect of the first image stabilization mode is larger than an image stabilization effect of the third image stabilization mode,

wherein a first determination mode that determines whether a state, where the shake amount is not higher than a first threshold, is maintained beyond first determination time is provided,

wherein a second determination mode that determines whether a state, where the shake amount is not higher than a second threshold that is smaller than the first threshold, is maintained beyond second determination time that is shorter than the first determination time is provided,

wherein said selection unit transfers the first image stabilization mode to the second image stabilization mode when the determination by the first determination mode is maintained beyond the first determination time,

wherein said selection unit transfers the first image stabilization mode to the third image stabilization mode when the determination by the second determination mode is maintained beyond the second determination time, and

wherein said selection unit does not transfer the first image stabilization mode to the second image stabilization mode while the determination by the second determination mode is maintained beyond third determination time that is shorter than the second determination time even when the determination by the first determination mode is maintained beyond the first determination time.

2. The image stabilization apparatus according to claim 1, wherein said selection unit transfers the first image stabilization mode to the third image stabilization mode when the determination by the second determination mode is maintained beyond the second determination time while the first determination mode is determined.

3. The image stabilization apparatus according to claim 1, wherein an image stabilization effect is a length of width of an image stabilization frequency band, the width of the image stabilization frequency band of the second image stabilization mode is longer than the width of the image stabilization frequency band of the first image stabilization mode, and the width of the image stabilization frequency band of the first image stabilization mode is longer than the width of the image stabilization frequency band of the third image stabilization mode.

4. The image stabilization apparatus according to claim 1, wherein the lower limit of the image stabilization frequency band of the second image stabilization mode is smaller than the lower limit of the image stabilization frequency band of the first image stabilization mode.

5. The image stabilization apparatus according to claim 1, wherein said control unit stops the image stabilization by said image stabilization unit when said selection unit selects the third image stabilization mode.

6. The image stabilization apparatus according to claim 1, wherein said selection unit transfers the second image stabilization mode to the first image stabilization mode when it is determined that the shake amount is not lower than a third threshold that is higher than the first threshold.

7. The image stabilization apparatus according to claim 1, wherein said selection unit transfers the third image stabilization mode to the first image stabilization mode when it is determined that the shake amount is not lower than a third threshold that is higher than the first threshold.

8. The image stabilization apparatus according to claim 6, wherein said selection unit transfers the first image stabilization mode to a panning mode, and increases cutoff frequency of a high-pass filter that extracts a specific frequency component from the output signal outputted from said shake detection unit, when it is determined that the shake amount is not lower than a fourth threshold that is higher than the third threshold.

9. An image pickup apparatus comprising:

a lens, and

an image stabilization apparatus comprising;

a shake detection unit configured to detect a shake amount of an image pickup apparatus;

an image stabilization unit configured to correct an image blur using an output signal outputted from said shake detection unit;

a selection unit configured to select one image stabilization mode from among at least three image stabilization modes including a first image stabilization mode, a second image stabilization mode, and a third image stabilization mode; and

a control unit configured to control said image stabilization unit according to the image stabilization mode selected by said selection unit,

wherein an image stabilization effect of the second image stabilization mode is larger than an image stabilization effect of the first image stabilization mode, and the image stabilization effect of the first image stabilization mode is larger than an image stabilization effect of the third image stabilization mode,

wherein a first determination mode that determines whether a state, where the shake amount is not higher than a first threshold, is maintained beyond first determination time is provided,

wherein a second determination mode that determines whether a state, where the shake amount is not higher than a second threshold that is smaller than the first threshold, is maintained beyond second determination time that is shorter than the first determination time is provided,

wherein said selection unit transfers the first image stabilization mode to the second image stabilization mode when the determination by the first determination mode is maintained beyond the first determination time,

wherein said selection unit transfers the first image stabilization mode to the third image stabilization mode when the determination by the second determination mode is maintained beyond the second determination time, and

wherein said selection unit does not transfer the first image stabilization mode to the second image stabilization mode while the determination by the second determination mode is maintained beyond third determination time that is shorter than the second determination time even when the determination by the first determination mode is maintained beyond the first determination time.

10. A control method for an image stabilization apparatus equipped with a shake detection unit that detects a shake amount of an image pickup apparatus and an image stabilization unit that corrects an image blur using an output signal outputted from the shake detection unit, the control method comprising:

a selection step of selecting one image stabilization mode from among at least three image stabilization modes including a first image stabilization mode, a second image stabilization mode, and a third image stabilization mode; and

a control step of controlling the image stabilization unit according to the image stabilization mode selected in said selection step,

wherein an image stabilization effect of the second image stabilization mode is larger than an image stabilization effect of the first image stabilization mode, and the image stabilization effect of the first image stabilization mode is larger than an image stabilization effect of the third image stabilization mode,

wherein a first determination mode that determines whether a state, where the shake amount is not higher than a first threshold, is maintained beyond first determination time is provided,

wherein a second determination mode that determines whether a state, where the shake amount is not higher than a second threshold that is smaller than the first threshold, is maintained beyond second determination time that is shorter than the first determination time is provided,

wherein the first image stabilization mode is transferred to the second image stabilization mode in said selection step when the determination by the first determination mode is maintained beyond the first determination time,

wherein the first image stabilization mode is transferred to the third image stabilization mode in said selection step when the determination by the second determination mode is maintained beyond the second determination time, and

wherein the first image stabilization mode is transferred to the second image stabilization mode in said selection step while the determination by the second determination mode is maintained beyond third determination time that is shorter than the second determination time even when the determination by the first determination mode is maintained beyond the first determination time.

11. An image stabilization apparatus comprising:

a shake detection unit configured to detect a shake amount of an image pickup apparatus;

an image stabilization unit configured to correct an image blur using an output signal outputted from said shake detection unit;

a selection unit configured to transfer a first image stabilization mode to a second image stabilization mode with a larger image stabilization effect when a state, where the shake amount is not higher than a first threshold, is maintained beyond first determination time and the shake amount is not maintained below a second threshold that is lower than the first threshold beyond third determination time that is shorter than second determination time, and to transfer the first image stabilization mode to a third image stabilization mode with the smallest image stabilization effect when a state, where the shake amount is not higher than the second threshold, is maintained beyond the second determination time that is shorter than the first determination time; and

a control unit configured to control said image stabilization unit in the selected image stabilization mode.

12. A control method for an image stabilization apparatus equipped with a shake detection unit that detects a shake amount of an image pickup apparatus and an image stabilization unit that corrects an image blur using an output signal outputted from the shake detection unit, the control method comprising:

a first selection step of transferring a first image stabilization mode to a second image stabilization mode with a larger image stabilization effect when a state, where the shake amount is not higher than a first threshold, is maintained beyond first determination time and the shake amount is not maintained below a second threshold that is lower than the first threshold beyond third determination time that is shorter than second determination time;

a second selection step of transferring the first image stabilization mode to a third image stabilization mode with the smallest image stabilization effect when a state, where the shake amount is not higher than the second threshold, is maintained beyond the second determination time that is shorter than the first determination time; and

a control step of controlling the image stabilization unit in the selected image stabilization mode.

13. An image stabilization apparatus comprising:

a shake detection unit configured to detect a shake amount of an image pickup apparatus;

an image stabilization unit configured to correct an image blur using an output signal outputted from said shake detection unit;

a first count unit configured to perform a first count used for determining whether a first image stabilization mode is transferred to a second image stabilization mode that is larger in an image stabilization effect than the first image stabilization mode;

a second count unit configured to perform a second count used for determining whether or not the first image stabilization mode is transferred to third image stabilization mode that is smaller in an image stabilization effect than the first image stabilization mode;

a transfer unit configured to transfer the first image stabilization mode to the second stabilization mode, when the shake amount falls below a first threshold, and the first count unit starts the first count and subsequently the first count exceeds a first determination time while the shake amount is maintained below the first threshold during the first count unit performing the first count,

wherein the transfer unit does not transfer the first image stabilization mode to the second stabilization mode, when the shake amount falls below a second threshold that is lower than the first threshold, and the second count unit starts the second count after the first count unit has started the first count, even when the first count exceeds the first determination time while the shake amount is maintained below the first threshold during the first count unit performing the first count.

14. The image stabilization apparatus according to claim 13, wherein the transfer unit does not transfer the first image stabilization mode to the second image stabilization mode when where the shake amount falls below the second threshold, and the second count is started after the first count has been started, and subsequently the second count exceeds third determination time that is shorter than second determination time while the shake amount is maintained below the second threshold during the second count unit performing the second count,

wherein the second determination time is used for determining whether or not the first image stabilization mode is transferred to the third image stabilization mode.

15. A control method for an image stabilization apparatus equipped with a shake detection unit configured to detect a shake amount of an image pickup apparatus and an image stabilization unit configured to correct an image blur using an output signal outputted from said shake detection unit, the control method comprising:

a first count step of performing a first count used for determining whether or not a first image stabilization mode is transferred to a second image stabilization mode that is larger in an image stabilization effect than the first image stabilization mode;

a second count step of performing a second count used for determining whether or not the first image stabilization mode is transferred to third image stabilization mode that is smaller in an image stabilization effect than the first image stabilization mode;

a transfer step of transferring the first image stabilization mode to the second stabilization mode, when the shake amount falls below a first threshold, and the first count has been started and subsequently the first count exceeds a first determination time while the shake amount is maintained below the first threshold during the first count being performed,

wherein the first image stabilization mode is not transferred to the second stabilization mode, when the shake amount falls below a second threshold that is lower than the first threshold, and the second count is started after the first count has been started, even when the first count exceeds the first determination time while the shake amount is maintained below the first threshold during the first count being performed.