Camera with Acceleration Sensor

• US 20090154910A1
• Filed: 02/20/2009
• Published: 06/18/2009
• Est. Priority Date: 02/01/2005
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Weinberg, Harvey, Lemaire, Christophe, Samuels, Howard, Judy, Michael
• Granted Patent: US 7,720,376 B2
• Time in Patent Office: Days
• US Class Current: 396/50
• CPC Class Codes: G03B 17/02 Bodies
• CPC Class Codes: G03B 17/20 visible in viewfinder
• CPC Class Codes: H04N 23/631 Graphical user interfaces [GUI] specially adapted for controlling image capture or setting capture parameters
• CPC Class Codes: H04N 23/633 for displaying additional information relating to control or operation of the camera
• CPC Class Codes: H04N 23/651 for reducing power consumption by affecting camera operations, e.g. sleep mode, hibernation mode or power off of selective parts of the camera
• CPC Class Codes: H04N 23/684 performed by controlling the image sensor readout, e.g. by controlling the integration time

Abstract

A method and system for determining camera positioning information from an accelerometer mounted on a camera. The accelerometer measures the orientation of the camera with respect to gravity. Orientation measurement allows user interface information to be displayed in a “right side up” orientation on a viewfinder for any camera orientation. Alternatively, an artificial horizon indicator may be displayed in the viewfinder. The accelerometer may also measure camera movement. Camera movement information together with camera orientation can be used to determine camera usage. Additionally, camera movement information can be used to determine a minimum shutter speed for a sharp picture.

Claims

1. A method for adjusting image exposure time for a camera comprising:

a. providing the camera, the camera including an accelerometer;

b. measuring a peak-to-peak acceleration magnitude for at least one camera axis using the accelerometer for a given time duration; and

c. adjusting the image exposure time based at least in part on the peak-to-peak acceleration magnitude for at least one camera axis over the given time duration.

2. A method according to claim 1 wherein the accelerometer is a MEMS.

3. A method according to claim 1, wherein adjusting the image exposure time includes calculating a minimum shutter speed.

4. A method according to claim 3, wherein the minimum shutter speed is calculated as a function of the square of the inverse of the peak-to-peak acceleration magnitude divided by the camera focal length.

5. A method according to claim 1, wherein the peak-to-peak acceleration magnitude is measured for more than one axis of the camera and adjusting the image exposure time camera is based on the maximum of the peak-to-peak acceleration magnitudes for the more than one axis of the camera over the given time duration.

6. A method according to claim 1, wherein adjusting the image exposure time includes looking up a minimum shutter speed versus the peak-to-peak acceleration magnitude over the given time duration in a look-up table.

7. A method for determining a state of utilization for a camera comprising:

a. providing the camera, the camera including an accelerometer for determining an orientation of the camera with respect to gravity and a peak-to-peak acceleration magnitude over a given time duration;

b. determining an orientation of the camera using the accelerometer;

c. determining a peak-to-peak acceleration magnitude over the given time duration using the accelerometer; and

d. identifying the state of utilization of the camera based at least in part on the camera orientation determination and the peak-to-peak acceleration magnitude over the given time duration.

8. A method according to claim 7 wherein the accelerometer is a MEMS.

9. A method according to claim 7 wherein identifying the state of utilization for the camera includes determining whether the peak-to-peak acceleration magnitude exceeds 15 mg.

10. A method according to claim 7 further including:

e. placing the camera in a lower power state based on the identified state of utilization.

11. A system for adjusting image exposure time for a camera comprising:

an accelerometer mounted on the camera for determining a peak-to-peak acceleration magnitude over a given time duration; and

a processor in the camera including a memory, the memory containing instructions that cause the processor to;

measure a peak-to-peak acceleration magnitude for at least one camera axis using the accelerometer for the given time duration; and

adjust the image exposure time based at least in part on the peak-to-peak acceleration magnitude for at least one camera axis over the given time duration.

12. A system according to claim 11 wherein the accelerometer is a MEMS.

13. A system according to claim 11, wherein the accelerometer is a solid state device.

14. A system according to claim 11, wherein adjusting the image exposure time includes calculating a minimum shutter speed.

15. A system according to claim 14, wherein the minimum shutter speed is calculated as a function of the square of the inverse of the peak-to-peak acceleration magnitude divided by the camera focal length.

16. A system for determining a state of utilization for a camera comprising:

an accelerometer mounted on the camera for determining an orientation of the camera with respect to gravity and a peak-to-peak acceleration magnitude over a given time duration; and

a processor in the camera including a memory, the memory containing instructions that cause the processor to;

determine an orientation of the camera using the accelerometer;

determine a peak-to-peak acceleration magnitude over the given time duration using the accelerometer; and

identify the state of utilization of the camera based at least in part on the camera orientation determination and the peak-to-peak acceleration magnitude over the given time duration.

17. A system according to claim 16 wherein identifying the state of utilization of the camera includes determining whether the peak-to-peak acceleration magnitude exceeds 15 mg.

18. A system according to claim 16 further including instructions that cause the processor to place the camera in a lower power state based on the identified state of utilization.

19. A system according to claim 16 wherein the accelerometer is a MEMS.