SYSTEMS AND METHODS FOR IMAGING OBJECTS

• US 20100073515A1
• Filed: 09/21/2009
• Published: 03/25/2010
• Est. Priority Date: 09/22/2008
• Status: Active Grant

• Current Assignee: Freedom Scientific Incorporated
• Original Assignee: Freedom Scientific Incorporated
• Inventors: CONARD, Todd
• Granted Patent: US 8,416,319 B2
• Time in Patent Office: Days
• US Class Current: 348/229.100
• CPC Class Codes: G09B 21/008 using visual presentation of the information for the partially sighted
• CPC Class Codes: H04N 23/681 Motion detection
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 23/72 Combination of two or more compensation controls
• CPC Class Codes: H04N 23/73 by influencing the exposure time
• CPC Class Codes: H04N 23/76 by influencing the image signals
• CPC Class Codes: H04N 5/144 Movement detection for video coding H04N19/503; analysis of motion in general G06T7/20

Abstract

Systems and methods for imaging objects are provided. An imaging device includes a sensor to provide an image of an object. The sensor can have a sensor exposure time and a sensor gain and the image includes a plurality of frames, each of the plurality of frames that can depict at least a portion of the object. The imaging device includes a motion detector to determine whether there is movement of the at least a portion of the object between adjacent frames of the plurality of frames. The imaging device also includes a controller. The controller can set the sensor exposure time to a first value in response to a determination by the motion detector that there is movement of the at least a portion of the object between adjacent frames. The controller can also set the sensor exposure time to a second value in response to a determination that there is no movement of the at least a portion of the object between adjacent frames. The controller can also adjust the sensor exposure time, the sensor gain, or both to maintain a luminance value of the plurality of frames at a target luminance value.

Claims

1. An imaging device, comprising:

a sensor configured to provide an image of an object, the sensor having a sensor exposure time and a sensor gain and the image including a plurality of frames, each of the plurality of frames depicting at least a portion of the object;

a motion detector to determine whether there is movement of the at least a portion of the object between adjacent frames of the plurality of frames;

a controller configured to set the sensor exposure time to a first value in response to a determination by the motion detector that there is movement of the at least a portion of the object between adjacent frames, and to set the sensor exposure time to a second value that is substantially different than the first value in response to a determination that there is no movement of the at least a portion of the object between adjacent frames;

the controller further being configured to adjust at least one of the sensor exposure time and the sensor gain to substantially maintain a luminance value of the plurality of frames at a target luminance value irrespective of whether the motion detector determines that there is movement of the at least a portion of the object between adjacent frames or not.

2. The imaging device of claim 1, wherein, during a period of time in which it is determined that there is movement of the at least a portion of the object between adjacent frames, the controller is configured to maintain the sensor exposure time at the first value and to adjust the sensor gain to substantially maintain the luminance value of the plurality of frames at the target luminance value.

3. The imaging device of claim 1, wherein, during a first portion of a period of time in which it is determined that there is no movement of the at least a portion of the object between adjacent frames, the controller is configured to maintain the sensor exposure time at the second value and to adjust the sensor gain to substantially maintain the luminance value of the plurality of frames at the target luminance value.

4. The imaging device of claim 3, wherein, during a second portion of the period of time in which it is determined that there is no movement of the at least a portion of the object between adjacent frames, the controller is further configured to maintain the sensor gain at a fixed gain value and to further adjust the sensor exposure time to a fixed exposure time value so that the luminance value of the plurality of frames is equal to the target luminance value.

5. The imaging device of claim 4, wherein, during a third portion of the period of time in which it is determined that there is no movement of the at least a portion of the object between adjacent frames, the controller is configured to maintain the sensor gain at the fixed gain value, and to maintain the sensor exposure time at the fixed exposure time value.

6. The imaging device of claim 5, wherein the third portion of the period of time is subsequent to the second portion of the period of time, and wherein the second portion of the period of time is subsequent to the first portion of the period of time.

7. The imaging device of claim 1, wherein the target luminance value is one of a first target color luminance value and a first target black and white luminance value, the device further comprising:

a color detector to determine whether the image is a color image or a black and white image;

wherein the controller is configured to adjust at least one of the sensor exposure time and the sensor gain to substantially maintain the luminance value of the plurality of frames at different first and second target luminance values dependent upon whether the image is determined to be the color image or the black and white image, the first and second target luminance values being greater for the color image than the black and white image.

8. The imaging device of claim 7, wherein the controller is further configured to adjust at least one of a contrast of the image and a saturation of the image to different values dependent upon whether the motion detector determines that there is movement of the at least a portion of the object between adjacent frames and dependent upon whether the image is a color image or a black and white image.

9. The imaging device of claim 7, wherein the color detector is implemented by the controller.

10. The imaging device of claim 1, wherein the motion detector is configured to determine that there is movement of the at least a portion of the object between adjacent frames in response to relative motion between the object and the sensor and in response to a change in magnification of the at least a portion of the object between adjacent frames.

11. The imaging device of claim 1, wherein the controller is configured to produce a magnified image between two and sixteen times greater than the image, the device further comprising:

a display unit configured to display the magnified image.

12. The imaging device of claim 11, wherein the level of magnification of the image is continuous.

13. The imaging device of claim 1, wherein:

the motion detector is configured to determine a luminance value difference that is a difference between a luminance of adjacent frames; and

the motion detector is configured to determine that there is movement of the at least a portion of the object between adjacent frames when the luminance value difference is greater than a threshold value.

14. The imaging device of claim 1, wherein the motion detector is configured to:

identify a plurality of quadrants of adjacent frames;

determine a luminance value of corresponding quadrants of adjacent frames; and

determine that there is movement of the at least a portion of the object between adjacent frames when a difference between the luminance value of the corresponding quadrants of adjacent frames exceeds a threshold value.

15. The imaging device of claim 1, wherein:

the motion detector is configured to determine that there is movement of the at least a portion of the object between adjacent frames based at least in part on a location of edges in adjacent frames.

16. The device of claim 1, wherein the motion detector is implemented by the controller.

17. The imaging device of claim 1, wherein the imaging device is configured to produce the same digital frame as the image during periods of time in which it is determined that there is no movement of the at least a portion of the object.

18. A method of imaging objects, comprising acts of:

generating an image of an object using a sensor, the image including a plurality of frames depicting at least a portion of the object;

determining whether there is movement between of the at least a portion of the object between adjacent frames of the plurality of frames;

setting, responsive to the act of determining, a sensor exposure time of the sensor to a first value when movement of the at least a portion of the object between adjacent frames is determined and setting the sensor exposure time of the sensor to a second value that is substantially different than the first value when no movement of the at least a portion of the object between adjacent frames is determined; and

adjusting at least one of the sensor exposure time and a sensor gain of the sensor to substantially maintain a luminance value of the plurality of frames at a target luminance value irrespective of whether movement of the at least a portion of the object between adjacent frames is determined or not.

19. The method of claim 18, wherein, during at least part of a period of time in which it is determined that there is movement of the at least a portion of the object between adjacent frames, the method further comprises:

maintaining the sensor exposure time at a first value; and

adjusting the sensor gain to substantially maintain the luminance value of the plurality of frames at the target luminance value.

20. The method of claim 18, wherein, during a first portion of a period of time in which it is determined that there is no movement of the at least a portion of the object between adjacent frames, the method further comprises:

maintaining the sensor exposure time the second value; and

adjusting the sensor gain to substantially maintain the luminance value of the plurality of frames at the target luminance value.

21. The method of claim 20, wherein, during a second portion of the period of time in which it is determined that there is no movement of the at least a portion of the object between adjacent frames, the method further comprises:

maintaining the sensor gain at a fixed gain value; and

adjusting the sensor exposure time to a fixed exposure time value so that the luminance value of the plurality of frames is equal to the target luminance value.

22. The method of claim 21, wherein, during a third portion of the period of time in which it is determined that there is no movement of the at least a portion of the object between adjacent frames, the method further comprises:

maintaining the sensor gain at the fixed gain value, and

maintaining the sensor exposure time at the fixed exposure value.

23. The method of claim 18, further comprising:

determining whether the image is a color image or a black and white image; and

adjusting at least one of the sensor exposure time and the sensor gain to substantially maintain the luminance value of the plurality of frames at different first and second target luminance values dependent upon whether the image is determined to be the color image or the black and white image, the first and second target luminance values being greater for the color image than the black and white image.

24. The method of claim 18, further comprising determining whether the image is a color image or a black and white image;

and

adjusting, responsive to a determination that the image is the color image, at least one of a contrast of the image and a saturation of the image.

25. The method of claim 18, comprising:

producing a magnified image of the image of the object, the magnified image between two and sixteen times greater than the image; and

providing at least a portion of the magnified image to a display unit.

26. The method of claim 18, comprising:

determining a delta luminance value difference that is a difference between a luminance of adjacent frames; and

determining that there is movement of the at least a portion of the object between adjacent frames when the luminance value difference is greater than a threshold value.

27. The method of claim 18, further comprising:

identifying a plurality of quadrants of adjacent frames;

determining a luminance value of corresponding quadrants of adjacent frames; and

determining that there is movement of the at least a portion of the object between adjacent frames when a difference between the luminance value of the corresponding quadrants of adjacent frames exceeds a threshold value.

28. The method of claim 18, wherein:

determining that there is movement of the at least a portion of the object between adjacent frames based at least in part on a location of edges in adjacent frames.

29. A computer readable medium encoded with instructions for execution on a processor, the instructions when executed, performing a method comprising acts of:

generating an image of an object using a sensor, the image including a plurality of frames depicting at least a portion of the object;

determining whether there is movement between of the at least a portion of the object between adjacent frames of the plurality of frames;

setting, responsive to the act of determining, a sensor exposure time of the sensor to a first value when movement of the at least a portion of the object between adjacent frames is determined and setting the sensor exposure time of the sensor to a second value that is substantially different than the first value when no movement of the at least a portion of the object between adjacent frames is determined; and

adjusting at least one of the sensor exposure time and a sensor gain of the sensor to substantially maintain a luminance value of the plurality of frames at a target luminance value irrespective of whether movement of the at least a portion of the object between adjacent frames is determined or not.