Camera exposure optimization techniques that take camera and scene motion into account

• US 7,546,026 B2
• Filed: 10/25/2005
• Issued: 06/09/2009
• Est. Priority Date: 10/25/2005
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Zoran Corporation (Qualcomm, Inc.)
• Inventors: Pertsel, Shimon, Meitav, Ohad, Pozniansky, Eli
• Primary Examiner(s): Mahoney; Christopher E
• Assistant Examiner(s): PARKER, AUTUMN H
• Application Number:
  US11/258,975
• Publication Number:
  US 20070092244A1
• Time in Patent Office: 1,323 Days
• Field of Search: 396/153, 396/49, 396/213, 396 52- 55, 348/255, 348/208.99, 348/208.1, 348/208.4, 348/208.5, 348/208.6, 348/208.14, 348/221.1
• US Class Current: 396/52
• CPC Class Codes: G03B 2217/005 Blur detection
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/684 performed by controlling the image sensor readout, e.g. by controlling the integration time

Abstract

Quantities of motion between images of an electronic camera are calculated and used to adjust the exposure time and one or more other exposure parameters used to capture an image in order to improve the quality of the image. Motion blur caused by movement of the camera or by movement of an object within the scene being photographed is reduced by selecting appropriate exposure parameters. Further, when there is little or no motion detected, the exposure parameters may be selected to improve the depth of field and reduce the noise in the captured image.

Claims

1. A method of operating an electronic imaging device as a camera, comprising:

repetitively acquiring data of two or more images of a scene,

calculating at least one quantity of motion of at least a portion of the scene relative to the camera from the acquired data of said two or more images such that the quantity of relative motion is independent of another quantity of total motion that is determined along each directional vector and which is calculated separately from a vector for acquiring data from at least the portion of the scene, and wherein the separate calculation of each directional vector further provides a velocity and an acceleration of the total motion;

preliminarily setting, from luminescence information within the data of said two or more images, parameters including a duration for capturing data of a final image of the scene without regard to the at least one quantity of relative motion;

in response to said at least one quantity of relative motion being below a first threshold, adjusting the preliminarily set parameters by at least increasing the duration of exposure;

in response to said at least one quantity of relative motion being above a second threshold, adjusting the preliminarily set parameters by decreasing at least the duration of exposure; and

thereafter capturing data of the final image of the scene by use of the adjusted duration and at least one other adjusted exposure parameter selected from a group comprising aperture size and gain.

2. The method of claim 1, wherein the first and second thresholds are the same.

3. The method of claim 1, wherein preliminarily setting parameters includes setting at least one other exposure parameter, and adjusting the preliminarily set parameters in response to said at least one quantity of relative motion being below a first threshold by additionally decreasing said at least one other exposure parameter, and adjusting the preliminarily set parameters in response to said at least one quantity of relative motion being above a second threshold by additionally increasing said at least one other exposure parameter.

4. The method of claim 3, wherein the first and second thresholds are the same.

5. The method of claim 3, wherein said at least one other exposure parameter includes a size of an aperture through which light of the image passes.

6. The method of claim 3, wherein said at least one other exposure parameter includes image gain.

7. The method of claim 6, wherein the image gain includes a level of gain of an analog signal carrying image information prior to capturing the data.

8. The method of claim 6, wherein capturing the data includes digitizing the captured data and adjusting the image gain includes adjusting a level of gain of the digitized image data.

9. The method of claim 1, wherein said at least one quantity of relative motion includes motion of the camera with respect to each portion of the scene.

10. The method of claim 1, wherein said at least one quantity of relative motion includes motion in the at least one portion of the scene.

11. The method of claim 1, which additionally comprises using said at least one quantity of relative motion to determine a time to capture data of the final image, and thereafter capturing said data of the final image.

12. The method of claim 11, wherein the time to capture data of the final image is determined to include an estimate of a time during a predefined interval when the relative motion is expected to be minimal or less than a predetermined threshold.

13. The method of claim 11, wherein calculating at least one quantity of relative motion includes estimating said at least one quantity at the time determined to capture data of the final image.

14. The method of claim 1, which additionally comprises, after preliminarily setting exposure parameters, determining whether the preliminarily set exposure parameters fall within predefined ranges, and if so, adjusting of the preliminarily set exposure parameters is omitted.

15. The method of claim 1, wherein acquiring data of two or more images of the scene includes acquiring data of two or more successive images having a resolution that is lower than a resolution of the final image.

16. The method of claim 1, wherein calculating at least one quantity of motion includes utilizing motion vectors within said at least a portion of the scene.

17. A processor-readable storage medium that includes data and instructions, wherein the execution of the instructions on an apparatus operating as a camera enables actions, comprising:

repetitively acquiring data of two or more images of a scene;

calculating at least one quantity of total motion of at least a portion of the scene relative to the camera from the acquired data of said two or more images such that the quantity of total motion is based, at least in part, on a global motion quantity and a plurality of local motion quantities that are independent of the global motion quantity, wherein the global motion is determined along each directional vector that is calculated separately from a vector for acquiring data from at least the portion of the scene, and wherein the separate calculation of each directional vector further provides a velocity and an acceleration of the global motion;

preliminarily setting, from luminescence information within the data of said two or more images, parameters including a duration for capturing data of a final image of the scene without regard to the at least one quantity of total motion;

in response to the at least one quantity of total motion being below a first threshold, adjusting the preliminarily set parameters by at least increasing the duration of exposure;

in response to the at least one quantity of total motion being above a second threshold, adjusting the preliminarily set parameters by decreasing at least the duration of exposure; and

capturing data of the final image of the scene by use of the adjusted duration and at least one other adjusted exposure parameter selected from a group comprising aperture size and gain.

18. The processor-readable storage medium of claim 17, wherein calculating the at least one quantity of total motion includes combining the global motion quantity with the weighted average of the local motion quantities.

19. The processor-readable storage medium of claim 17, wherein the global motion quantity is associated with motion of the camera with respect to each portion of the scene.

20. An apparatus arranged to operate as a camera, comprising:

a memory for storing instructions; and

a processor that is configured to enable actions based on execution of the instructions, including;

repetitively acquiring data of two or more images of a scene;

calculating at least one quantity of total motion of at least a portion of the scene relative to the camera from the acquired data of said two or more images such that the quantity of total motion is based, at least in part, on a global motion quantity and a plurality of local motion quantities that are independent of the global motion quantity, wherein the global motion quantity is determined along each directional vector that is calculated separately from a vector for acquiring data from at least the portion of the scene, and wherein the separate calculation of each directional vector further provides a velocity and an acceleration of the global motion;

preliminarily setting, from luminescence information within the data of said two or more images, parameters including a duration for capturing data of a final image of the scene without regard to the at least one quantity of total notion;

in response to the at least one quantity of total motion being below a first threshold, adjusting the preliminarily set parameters by at least increasing the duration of exposure;

in response to the at least one quantity of total motion being above a second threshold, adjusting the preliminarily set parameters by decreasing at least the duration of exposure; and

capturing data of the final image of the scene by use of the adjusted duration and at least one other adjusted exposure parameter selected from a group comprising aperture size and gain.