IMAGE CAPTURING APPARATUS, CONTROL METHOD, and PROGRAM THEREOF

• US 20150015774A1
• Filed: 07/09/2014
• Published: 01/15/2015
• Est. Priority Date: 07/11/2013
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Sugie, Kazuhiko
• Granted Patent: US 9,485,434 B2
• Time in Patent Office: Days
• US Class Current: 348/364
• CPC Class Codes: G03B 7/00 Control of exposure by setting shutters, diaphragms or filters, separately or conjointly control of exposure in television cameras by means of circuitry influencing the optical part of the camera H04N23/75
• CPC Class Codes: G06T 2207/20208 High dynamic range [HDR] image processing
• 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 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 23/741 by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
• CPC Class Codes: H04N 25/58 involving two or more exposures

Abstract

An image capturing apparatus includes an image capturing unit which captures an image of an object and outputs an image, a switching unit which switches modes between a first mode in which the image capturing unit outputs a first image and then outputs a second image having an exposure value different from the first image, and a second mode in which the image capturing unit continuously outputs an image not used for compositing, an exposure control unit which controls an exposure value for capturing an image of an object, following change in object luminance, when a parameter related to change in object luminance exceeds a predetermined range in which an exposure value for capturing an image of the object is not controlled to follow the change in object luminance, and a setting unit which sets the predetermined range.

Claims

1. An image capturing apparatus comprising:

an image capturing unit configured to capture an image of an object and to output an image;

a switching unit configured to switch modes between a first mode in which the image capturing unit outputs a first image and then outputs a second image having an exposure value different from the first image, and a second mode in which the image capturing unit continuously outputs an image not used for compositing;

an exposure control unit configured to control an exposure value for capturing an image of an object, following change in object luminance, when a parameter related to change in object luminance exceeds a predetermined range; and

a setting unit configured to set the predetermined range,

wherein the first image and the second image are used for compositing,

wherein the predetermined range is a range in which an exposure value is not controlled to follow the change in the object luminance for capturing an image of the object,

wherein the setting unit sets a first range as the predetermined range in the first mode, and

wherein the setting unit sets a second range which is narrower than the first range as the predetermined range in the second mode.

2. The image capturing apparatus according to claim 1, further comprising:

an exposure difference setting unit configured to set exposure value difference between the first image and the second image in the first mode, and

an exposure value adjusting unit configured to adjust an exposure value of the first image and the second image based on an exposure value difference between the first image and the second image set by the exposure difference setting unit, and

wherein the exposure value adjusting unit adjusts an exposure value of the first image and the second image also in the predetermined range.

3. The image capturing apparatus according to claim 2,

wherein the exposure difference setting unit sets a width of the first range which is the predetermined range in the first mode based on an exposure value difference between the first image and the second image set by the exposure difference setting unit.

4. The image capturing apparatus according to claim 1,

wherein the exposure control unit controls an exposure value for capturing an image of an object maintaining the first mode when a parameter related to change in object luminance exceeds the first range in the first mode.

5. The image capturing apparatus according to claim 1,

wherein the parameter related to change in object luminance is target luminance for capturing an image of an object, and

wherein the setting unit sets the predetermined range so that a center of the predetermined range is in a location different from shooting luminance corresponding to an exposure value for capturing an image of an object.

6. The image capturing apparatus according to claim 1,

wherein the parameter related to change in object luminance is a target exposure value corresponding to target luminance for capturing an image of an object, and

wherein the setting unit sets the predetermined range so that a center of the predetermined range is in a location different from shooting exposure value which is an exposure value for capturing an image of the object.

7. The image capturing apparatus according to claim 1,

wherein the parameter related to change in object luminance is an elapsed time after change in object luminance, and

wherein the exposure control unit controls the exposure value, following change in object luminance, for capturing an image of an object when an elapsed time after change in object luminance exceeds a predetermined time which is the predetermined range.

8. The image capturing apparatus according to claim 1, further comprising:

a composite unit configured to composite the first image and the second image,

wherein the first image and the second image output after the first image are composited as a set.

9. The image capturing apparatus according to claim 5,

wherein the first image has a smaller exposure value than the second image, and

wherein the setting unit sets the predetermined range so that a center of the predetermined range is located in a higher luminance side than the shooting luminance.

10. The image capturing apparatus according to claim 6,

wherein the first image has a smaller exposure value than the second image, and

wherein the setting unit sets the predetermined range so that a center of the predetermined range is located in a larger exposure value side than the shooting exposure value.

11. The image capturing apparatus according to claim 5,

wherein the first image has a larger exposure value than the second image, and

wherein the setting unit sets the predetermined range so that a center of the predetermined range is located in a smaller luminance side than the shooting luminance.

12. The image capturing apparatus according to claim 6,

wherein the first image has a larger exposure value than the second image, and

wherein the setting unit sets the predetermined range so that a center of the predetermined range is located in a smaller exposure value side than the shooting exposure value.

13. A control method of an image capturing apparatus including an image capturing unit which captures an image of an object and outputs an image, the method comprising:

a switching step which switches modes between a first mode in which the image capturing unit outputs a first image and then outputs a second image having an exposure value different from the first image, and a second mode in which the image capturing unit continuously outputs an image not used for compositing;

an exposure control step in which an exposure value for capturing an image of an object, following change in object luminance, is controlled when a parameter related to change in object luminance exceeds a predetermined range; and

a setting step which sets the predetermined range,

wherein the first image and the second step are used for compositing,

wherein the predetermined range is a range in which an exposure value is not controlled to follow change in object luminance for capturing an image of an object,

wherein the setting step sets a first range as the predetermined range in the first mode, and

wherein the setting step sets a second range which is narrower than the first range as the predetermined range in the second mode.

14. A non-transitory computer-readable storage medium which stores a program configured to command a computer to execute the control method according to claim 13 and can be read out by the computer.