Depth Sensor and Method of Operating the Same

• US 20150130904A1
• Filed: 01/08/2014
• Published: 05/14/2015
• Est. Priority Date: 11/12/2013
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Bae, Kwang Hyuk, KIM, Tae Chan, CHO, Shung Han, KYUNG, Kyu Min
• Granted Patent: US 9,568,607 B2
• 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 7/4915 Time delay measurement, e.g. operational details for pixel components signal extraction and conditioning G01S7/493; Phase measurement

Abstract

A method of operating a depth sensor includes generating a first photo gate signal and second through fourth photo gate signals respectively having 90-, 180- and 270-degree phase differences from the first photo gate signal, applying the first photo gate signal and the third photo gate signal to a first row of a pixel array and the second photo gate signal and the fourth photo gate signal to a second row adjacent to the first row in a first frame using a first clock signal, and applying the first photo gate signal and the third photo gate signal to a first column of the pixel array and the second photo gate signal and the fourth photo gate signal to a second column adjacent to the first column in a second frame using a second clock signal.

Claims

1. A method of operating a depth sensor, the method comprising:

generating a first photo gate signal and second through fourth photo gate signals respectively having 90-, 180- and 270-degree phase differences from the first photo gate signal;

applying the first photo gate signal and the third photo gate signal to a first row of a pixel array and the second photo gate signal and the fourth photo gate signal to a second row adjacent to the first row in a first frame using a first clock signal; and

applying the first photo gate signal and the third photo gate signal to a first column of the pixel array and the second photo gate signal and the fourth photo gate signal to a second column adjacent to the first column in a second frame using a second clock signal,

wherein a frequency of the first clock signal is different from a frequency of the second clock signal.

2. The method of claim 1, further comprising:

interpolating pixel signals output from respective pixels comprised in the pixel array; and

generating image data based on interpolated pixel signals.

3. The method of claim 2, wherein the interpolating the pixel signals comprises:

interpolating a pixel signal of a first pixel in the first row based on a pixel signal of at least one second pixel in the second row in the first frame; and

interpolating the pixel signal of the second pixel in the second row based on a pixel signal of at least one first pixel in the first row in the first frame.

4. The method of claim 3, wherein the interpolating the pixel signal of the first pixel in the first row based on the pixel signal of the at least one second pixel in the second row comprises applying a weight corresponding to an offset of each of the at least one second pixel to the pixel signal of each at least one second pixel;

and

the interpolating the pixel signal of the second pixel in the second row based on the pixel signal of the at least one first pixel in the first row comprises applying a weight corresponding to an offset of each of the at least one first pixel to the pixel signal of each at least one first pixel.

5. The method of claim 4, wherein the weight is calculated based on a Gaussian function.

6. The method of claim 3, wherein the interpolating the pixel signals further comprises:

interpolating the pixel signal of the first pixel in the first column based on the pixel signal of the at least one second pixel in the second column in the second frame; and

interpolating the pixel signal of the second pixel in the second column based on the pixel signal of the at least one first pixel in the first column in the second frame.

7. The method of claim 6, wherein the interpolating the pixel signal of the first pixel in the first column based on the pixel signal of the at least one second pixel in the second column comprises applying a weight corresponding to an offset of each of the at least one second pixel to the pixel signal of each at least one second pixel;

and

the interpolating the pixel signal of the second pixel in the second column based on the pixel signal of the at least one first pixel in the first column comprises applying a weight corresponding to an offset of each of the at least one first pixel to the pixel signal of each at least one first pixel.

8. The method of claim 7, wherein the weight is calculated based on a Gaussian function.

9. A depth sensor comprising:

a photo gate signal generator configured to generate a first photo gate signal and second through fourth photo gate signals respectively having 90-, 180- and 270-degree phase differences from the first photo gate signal; and

a row and column selector configured to apply the first through fourth photo gate signals to rows or columns of a pixel array, the row and column selector applying the first photo gate signal and the third photo gate signal to a first row of the pixel array and the second photo gate signal and the fourth photo gate signal to a second row adjacent to the first row in a first frame using a first clock signal and applying the first photo gate signal and the third photo gate signal to a first column of the pixel array and the second photo gate signal and the fourth photo gate signal to a second column adjacent to the first column in a second frame using a second clock signal,

wherein a frequency of the first clock signal is different from a frequency of the second clock signal.

10. The depth sensor of claim 9, further comprising an image signal processor configured to interpolate pixel signals output from respective pixels comprised in the pixel array and to generate image data based on interpolated pixel signals.

11. The depth sensor of claim 10, wherein the image signal processor interpolates a pixel signal of a first pixel in the first row based on a pixel signal of at least one second pixel in the second row in the first frame and interpolates the pixel signal of the second pixel in the second row based on a pixel signal of at least one first pixel in the first row in the first frame.

12. The depth sensor of claim 11, wherein the image signal processor applies a weight corresponding to an offset of each of the at least one second pixel to the pixel signal of each at least one second pixel when interpolating the pixel signal of the first pixel in the first row based on the pixel signal of the at least one second pixel in the second row and applies a weight corresponding to an offset of each of the at least one first pixel to the pixel signal of each at least one first pixel when interpolating the pixel signal of the second pixel in the second row based on the pixel signal of the at least one first pixel in the first row.

13. The depth sensor of claim 10, wherein the image signal processor interpolates the pixel signal of the first pixel in the first column based on the pixel signal of the at least one second pixel in the second column in the second frame and interpolates the pixel signal of the second pixel in the second column based on the pixel signal of the at least one first pixel in the first column in the second frame.

14. The depth sensor of claim 13, wherein the image signal processor applies a weight corresponding to an offset of each of the at least one second pixel to the pixel signal of each at least one second pixel when interpolating the pixel signal of the first pixel in the first column based on the pixel signal of the at least one second pixel in the second column and applies a weight corresponding to an offset of each of the at least one first pixel to the pixel signal of each at least one first pixel when interpolating the pixel signal of the second pixel in the second column based on the pixel signal of the at least one first pixel in the first column.

15. The depth sensor of claim 14, wherein the weight is calculated based on a Gaussian function.

16. A method of operating a depth sensor, the method comprising:

interpolating pixel signals output from pixels of first and second adjacent rows of a pixel array in a first frame;

interpolating pixel signals output from first and second adjacent columns of the pixel array in a second frame, wherein the pixel signals of the first frame are generated using a first clock signal and the pixel signals of the second frame are generated using a second clock signal different than the first clock signal; and

generating image data based on the interpolated pixel signals.

17. The method of claim 16, wherein the pixel signals of the first row are generated by a first pair of photo gate signals out of phase with each other and the pixel signals of the second row are generated by a second pair of photo gate signals out of phase with each other, and

wherein the pixel signals of the first column are generated by the first pair of photo gate signals and the pixel signals of the second column are generated by the second pair of photo gate signals.

18. The method of claim 16, wherein the pixel signals of the first frame and the pixel signals of the second frame are each generated by first, second, third and fourth photo gate signals, the second, third and fourth photo gate signals respectively having 90-, 180- and 270-degree phase differences from the first photo gate signal, and

wherein the first and third photo gate signals are applied to the first row and first column and the second and fourth photo gate signals are applied to the second row and second column.

19. The method of claim 16, wherein the interpolating the pixel signals comprises:

interpolating a pixel signal of a first pixel in the first row based on a pixel signal of a second pixel in the second row;

interpolating the pixel signal of the second pixel in the second row based on a pixel signal of the first pixel in the first row;

interpolating a pixel signal of a first pixel in the first column based on a pixel signal of a second pixel in the second column; and

interpolating the pixel signal of the second pixel in the second column based on the pixel signal of the first pixel in the first column.

20. The method of claim 19, wherein the interpolating the pixel signal of the first pixel in the first row based on the pixel signal of the second pixel in the second row comprises applying a weight corresponding to a reflected signal offset of the second pixel to the pixel signal of the second pixel;

the interpolating the pixel signal of the second pixel in the second row based on the pixel signal of the first pixel in the first row comprises applying a weight corresponding to a reflected signal offset of the first pixel to the pixel signal of the first pixel;

the interpolating the pixel signal of the first pixel in the first column based on the pixel signal of the second pixel in the second column comprises applying a weight corresponding to a reflected signal offset of the second pixel to the pixel signal of the second pixel; and

the interpolating the pixel signal of the second pixel in the second column based on the pixel signal of the first pixel in the first column comprises applying a weight corresponding to a reflected signal offset of the first pixel to the pixel signal of the first pixel.