CAPTURING GATED AND UNGATED LIGHT IN THE SAME FRAME ON THE SAME PHOTOSURFACE

• US 20120154535A1
• Filed: 12/15/2010
• Published: 06/21/2012
• Est. Priority Date: 12/15/2010
• Status: Abandoned Application

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Yahav, Giora, Felzenshtein, Shlomo, Larry, Eli
• Application Number:
  US12/968,775
• Publication Number:
  US 20120154535A1
• Time in Patent Office: Days
• US Class Current: 348/46
• CPC Class Codes: G01S 17/894 3D imaging with simultaneous measurement of time-of-flight at a 2D array of receiver pixels, e.g. time-of-flight cameras or flash lidar
• CPC Class Codes: G01S 7/4863 Detector arrays, e.g. charge-transfer gates
• CPC Class Codes: H01L 27/14812 Special geometry or disposition of pixel-elements, address lines or gate-electrodes
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 25/441 by reading contiguous pixels from selected rows or columns of the array, e.g. interlaced scanning
• CPC Class Codes: H04N 25/533 by using differing integration times for different sensor regions
• CPC Class Codes: H04N 25/771 comprising storage means other than floating diffusion

Abstract

A photosensitive surface of an image sensor, hereafter a photosurface, of a gated 3D camera is controlled to acquire both gated and ungated light in the same frame on different areas of its surface. One image capture area of the photosurface acquires gated light during a gated period while another image capture area is OFF for image data capture purposes. During an ungated period, the other image capture area of the same photosurface captures ungated light as image data. Typically, the gated and ungated periods are interleaved during the same frame period.

Claims

1. A system for controlling a photosurface to capture gated and ungated light from a scene in a same frame period comprising:

a photosurface of an image sensor;

a first image capture area of the photosurface;

a second image capture area of the same photosurface;

control circuitry for controlling capture by the first image capture area of gated light as image data during a gated period within the frame period;

the second image capture area being in an OFF state in which image data is not captured during the gated period;

the control circuitry controlling capture by the second image capture area of ungated light as image data during an ungated period within the same frame period; and

the first image capture area being in an OFF state in which image data is not captured during the ungated period.

2. The system of claim 1 wherein the gated and ungated periods are interleaved during the same frame period.

3. The system of claim 2 further comprising:

the gated period comprises one or more short capture periods, each short capture period lasting about a pulse width of a light pulse which is less than 100 nanoseconds;

the control circuitry for controlling capture by the first image capture area by gating the first image capture area between an ON state in which image data is captured for each short capture period and the OFF state in which image data is not captured;

the ungated period comprises one or more long capture periods, each long capture period being longer than each short capture period to capture more reflected light from a scene for normalization of the image data captured during the gated period, each long capture period lasting less than 100 nanoseconds; and

the control circuitry controlling capture by the second image capture area by gating the second image capture area between the ON state for each long capture period and the OFF state.

4. The system of claim 1 wherein the photosurface is an interline photosurface comprising lines of photopixels.

5. The system of claim 1 wherein the photosurface is one of the group consisting of:

a charge coupled device (CCD);

or

a complementary metal oxide silicon (CMOS) device.

6. The system of claim 4 wherein the first image capture area comprises an area of alternating lines of pixels, and the second image capture area comprises an area of different alternating lines of pixels.

7. The system of claim 3 further comprising

one or more image data storage media;

the control circuitry controlling capture by the first image capture area of gated light during a gated period includes storing image data from light received during short capture periods by the first image capture area in the one or more image data storage media during the same gated period; and

the control circuitry controlling capture by the second image capture area of ungated light as image data during an ungated period includes storing image data from light received during long capture periods by the second image capture area in the one or more image data storage media during the same ungated period.

8. The system of claim 7, wherein:

the gated period is about 10 microseconds and the ungated period is about 10 microseconds.

9. The system of claim 7 wherein each of the image capture areas includes light sensitive photo pixels and the one or more image data storage media include a storage pixel associated with each of the photo pixels.

10. The system of claim 7 wherein each of the image capture areas includes light sensitive photo pixels and the one or more image data storage media include CMOS transistors for storing voltages representing image data.

11. A method for capturing interleaved gated and ungated light from a scene in a same frame period on the same photosurface comprising:

capturing gated light as image data during a gated period within the frame period by a first image capture area of a photosurface of an image sensor;

capturing ungated light as image data during an ungated period within the same frame period by a second image capture area of the same photosurface;

turning the second image capture area to an OFF state in which image data is not captured by the second image capture area for the gated period;

turning the first image capture area to an OFF state in which image data is not captured by the first image capture area for the ungated period; and

alternating the capturing gated light and the capturing ungated light on the same photosurface within in less than 2 microseconds.

12. The method of claim 11 further comprising:

the gated period comprises one or more short capture periods, each short capture period being less than 50 nanoseconds in duration;

the capturing gated light as image data during a gated period within the frame period by a first image capture area comprises gating the first image capture area between an ON state for each short capture period in which image data is captured and the OFF state in which image data is not captured;

the ungated period comprises one or more long capture periods, each long capture period being longer than each short capture period and less than 100 nanoseconds in duration; and

the capturing ungated light as image data during an ungated period within the same frame period by a second image capture area comprises gating the second image capture area between the ON state for each long capture period and the OFF state.

13. The method of claim 11 wherein

capturing gated light as image data during a gated period within the frame period by a first image capture area further comprises storing image data in image storage media associated with the first image capture area for the one or more short capture periods during each gated period of the frame;

and

capturing ungated light as image data during the ungated period within the frame period by the second image capture area further comprises storing image data in image storage media associated with the second image capture area for the one or more long capture periods during each ungated period of the frame.

14. In a three-dimensional (3D) time of flight camera system, a system for controlling a photosurface to capture gated and ungated light from a scene in a same frame period, the system comprising:

the same photosurface comprising a first image capture area comprising a first set of lines of photopixels and image data storage media for capturing gated light as image data during a gated period within the frame period and a second image capture area comprising a second set of lines of photopixels and image data storage media for capturing ungated light as image data during an ungated period within the same frame period; and

control circuitry electrically connected to the image capture areas for

causing storage of image data sensed by the first set of lines of photopixels to respective image data storage media of the first capture area during the gated period,

causing the second image capture area to be in an OFF state in which image data is not stored in the respective image data storage media for the second set of lines of photopixels for the entire gated period,

causing storage of image data sensed by the second set of lines of photopixels to respective image data storage media of the second capture area during the ungated period, and

causing the first image capture area to be in the OFF state in which image data is not stored in the respective image data storage media for the first set of lines of photopixels for the entire ungated period.

15. The system of claim 14 wherein the gated and ungated periods are interleaved during the same frame period.

16. The system of claim 15 further comprising:

the gated period comprises one or more short capture periods, each short capture period being of less than 100 nanoseconds;

the causing storage of image data sensed by the first set of lines of photopixels to respective image data storage media of the first capture area during the gated period comprises storing image data captured during each short capture period;

the ungated period comprises one or more long capture periods, each long capture period being longer than each short capture period and less than 100 nanoseconds in duration; and

the causing storage of image data sensed by the second set of lines of photopixels to respective image data storage media of the second capture area during the ungated period comprises storing image data captured during each long capture period.

17. The system of claim 16 wherein the interline photosurface is a CMOS sensor.

18. The system of claim 16 further comprising:

the image data storage media are storage pixels, each storage pixel storing image data for one of the photopixels;

each pixel including an electrode and sharing a substrate of the photosurface;

the control circuitry generating a voltage difference across the substrate and electrodes of pixels of the first set of lines during the gated period for causing storage of image data by the storage pixels of the first set and generating a voltage difference across the substrate and electrodes of pixels of the second set of lines during the gated period for inhibiting storage of image data by storage pixels of the second set during the gated period by the second set of lines; and

the control circuitry generating a voltage difference across the substrate and electrodes of pixels of the second set of lines during the ungated period for causing storage of image data by the storage pixels of the second set and generating a voltage difference across the substrate and electrodes of pixels of the first set of lines during the ungated period for inhibiting storage of image data by the storage pixels of the first set during the ungated period by the first set of lines.

19. The system of claim 18 wherein the photosurface is an interline photosurface.

20. The system of claim 19 wherein the interline photosurface is a charge coupled device (CCD) sensor.