Control device, apparatus, and control method for tracking correction based on multiple calculated control gains

• US 10,594,939 B2
• Filed: 04/21/2016
• Issued: 03/17/2020
• Est. Priority Date: 04/22/2015
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Wakamatsu, Nobushige
• Primary Examiner(s): Boylan, James T
• Application Number:
  US15/134,619
• Publication Number:
  US 20160316123A1
• Time in Patent Office: 1,426 Days
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments
• CPC Class Codes: H04N 23/61 based on recognised objects
• CPC Class Codes: H04N 23/611 where the recognised objects include parts of the human body
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 23/682 Vibration or motion blur correction
• CPC Class Codes: H04N 23/687 by shifting the lens or sensor position

Abstract

A control device configured to track a subject by controlling a correcting lens so that the subject is moved to a target position of a photographed image. The control device performs feedback control so that a difference between a position of the subject and a target position of the subject in the photographed image becomes small. The control device detects a photographing condition and changes a degree of tracking of the subject by changing a control gain in the feedback control based on the detected photographing condition.

Claims

1. A control device that corrects a shake of imaging apparatus and that tracks a subject using a correcting lens moving the subject in a photographed image, the device comprising:

at least one processor or circuit configured to perform the operations of the following units;

a first calculating unit configured to calculate a shake correction amount for correcting the shake of the imaging apparatus on the basis of an output of an angular velocity meter;

a second calculating unit configured to calculate a tracking correction amount as a control amount for tracking the subject on the basis of an output of an image sensor; and

a control unit configured to control the correcting lens on the basis of a lens drive amount obtained by adding the shake correction amount and the tracking correction amount, so that a difference between a position of the subject and a center of the photographed image becomes smaller,

wherein the control unit changes a control gain of the tracking correction amount based on a detected photographing condition to change a degree of tracking of the subject,

wherein the control unit calculates a plurality of control gains by different processing,

wherein the control unit selects the control gain having a minimum tracking correction amount from the plurality of calculated control gains when shake correction is turned ON and tracking correction is turned ON.

2. The control device according to claim 1,

wherein the control unit calculates a control gain among the plurality of control gains so that the degree of tracking of the subject becomes smaller in the case in which a focal distance of a photographing optical system is larger than a predetermined value in comparison to the case in which the focal distance is smaller than the predetermined value.

3. The control device according to claim 1,

wherein the control unit calculates a control gain among the plurality of control gains so that the degree of tracking of the subject becomes smaller in the case in which a photographing magnification of a photographing optical system is larger than a predetermined value in comparison to the case in which the photographing magnification is smaller than the predetermined value.

4. The control device according to claim 1,

wherein the control unit calculates a control gain among the plurality of control gains so that the degree of tracking of the subject becomes smaller in the case in which an electronic zoom magnification is larger than a predetermined value in comparison to the case in which the electronic zoom magnification is smaller than the predetermined value.

5. The control device according to claim 1,

wherein the control unit calculates a control gain among the plurality of control gains so that the degree of tracking of the subject becomes smaller in the case in which a frame rate of the plurality of photographed images is smaller than a predetermined value in comparison to the case in which the frame rate of the plurality of photographed images is larger than the predetermined value.

6. The control device according to claim 1,

wherein the control unit calculates a control gain among the plurality of control gains so that the degree of tracking of the subject becomes smaller in the case in which reliability of the detected subject is lower than a predetermined value in comparison to the case in which the reliability of the detected subject is higher than the predetermined value.

7. The control device according to claim 1,

wherein the control unit calculates a control gain among the plurality of control gains so that the degree of tracking of the subject to be smaller in the case in which a shake amount of the control device exceeds a threshold value in comparison to the case in which a shake amount of the control device does not exceed the threshold value.

8. The control device according to claim 1,

wherein the control unit calculates a count value to track the subject based on a difference between a position of the subject and a target position of the subject in the photographed image and performs control so that the subject is moved to the target position by adding the count value to a control amount used to track the subject for each sampling time,

wherein the control unit changes a control gain of the count value based on the detected photographing condition to change a degree of tracking of the subject.

9. A method of controlling and correcting a shake of an imaging apparatus and tracking a subject using a correcting lens moving the subject in a photographed image, the method comprising;

calculating a shake correction amount for correcting the shake of the imaging in apparatus on the basis of an output of an angular velocity meter;

calculating a tracking correction amount as a control amount for tracking the subject on the basis of an output of an image sensor; and

controlling the correcting lens on the basis of a lens drive amount obtained by adding the shake correction amount and the tracking correction amount, so that a difference between a position of the subject and a center of the photographed image becomes smaller,

wherein controlling step changes a control gain of the tracking correction amount based on a detected photographing condition to change a degree of tracking of the subject,

wherein the controlling step also calculates a plurality of control gains by different processing,

wherein the controlling step also selects the control gain having a minimum tracking correction amount from the plurality of calculated control gains when shake correction is turned ON and tracking correction is turned ON.