Apparatus and method of obtaining depth image

• US 20100051836A1
• Filed: 02/17/2009
• Published: 03/04/2010
• Est. Priority Date: 08/27/2008
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Seong Jin
• Granted Patent: US 8,217,327 B2
• Time in Patent Office: Days
• US Class Current: 250/574
• CPC Class Codes: G01S 17/36 with phase comparison between the received signal and the contemporaneously transmitted signal
• 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 7/483 Details of pulse systems

Abstract

An apparatus for obtaining a depth image. A first ray emission unit emits a first emission ray, a second ray emission unit emits a second emission ray, a receiving unit receives a first reflection ray associated with the first emission ray and a second reflection ray associated with the second emission ray, and a processing unit calculates a depth value corresponding to a first pixel, based on an electric charge provided from the first pixel of the receiving unit.

Claims

1. An apparatus for obtaining a depth image, the apparatus comprising:

a first ray emission unit to emit a first emission ray;

a second ray emission unit to emit a second emission ray;

a receiving unit to receive a first reflection ray associated with the first emission ray and a second reflection ray associated with the second emission ray; and

a processing unit to calculate a depth value corresponding to a first pixel of the receiving unit, based on a charge provided from the first pixel of the receiving unit.

2. The apparatus of claim 1, wherein the first ray emission unit and the second ray emission unit comprise infrared light-emitting diodes (LED).

3. The apparatus of claim 1, wherein the receiving unit comprises a plurality of pixels which generate charges in proportion to an amount of light within a received ray.

4. The apparatus of claim 1, wherein a pulse width of the first emission ray is different from a pulse width of the second emission ray.

5. The apparatus of claim 1, wherein the first ray emission unit and the second ray emission unit are symmetrically arranged based on the receiving unit.

6. The apparatus of claim 1, further comprising:

a control unit to control at least one of the first ray emission unit, the second ray emission unit, and the receiving unit.

7. The apparatus of claim 6, wherein the control unit provides a first control signal which is in-phase with the first emission ray in a first mode of operation of the receiving unit, and provides a second control signal having a first phase difference with the first emission ray in a second mode of operation of the receiving unit.

8. The apparatus of claim 7, wherein the first phase difference is 180 degrees.

9. The apparatus of claim 7, wherein the processing unit calculates the depth value corresponding to the first pixel based on a first charge and a second charge, the first charge being provided from the first pixel of the receiving unit in the first mode, the second charge being provided from the first pixel of the receiving unit in the second mode.

10. The apparatus of claim 9, wherein the processing unit calculates a first Time of Flight (TOF) value based on the first charge and the second charge, calculates the depth value corresponding to the first pixel of the receiving unit based on the first TOF value when the first TOF value is equal to or less than a pulse width of the first emission ray and a pulse width of the second emission ray, calculates a second TOF value based on the first charge and the second charge, and calculates the depth value corresponding to the first pixel of the receiving unit based on the second TOF value, when the first TOF value is greater than any one of the pulse width of the first emission ray and the pulse width of the second emission ray.

11. The apparatus of claim 10, wherein the depth value corresponding to the first pixel of the receiving unit=c*(TOF value)/2, the TOF value being either the first TOF value or the second TOF value, and c being the speed of light constant.

12. The apparatus of claim 1, wherein a pulse width of the second emission ray is twice as wide as a pulse width of the first emission ray.

13. A method of obtaining a depth image, the method comprising:

emitting a first emission ray and a second emission ray;

measuring charges respectively generated by a reflection ray of the first emission ray and a reflection ray of the second emission ray.

14. The method of claim 13, wherein a pulse width of the first emission ray is different from a pulse width of the second emission ray.

15. The method of claim 13, wherein the measuring comprises:

measuring a first charge based on a first control signal which is in-phase with the first emission ray; and

measuring a second charge based on a second control signal having a first phase difference with the first emission ray.

16. The method of claim 15, wherein the first phase difference is 180 degrees.

17. The method of claim 15, wherein the second control signal has a phase difference of 180 degrees with the first control signal.

18. The method of claim 15, further comprising:

calculating a depth value corresponding to a first pixel based on the first charge and the second charge.

19. The method of claim 18, wherein the calculating comprises:

calculating a first TOF value based on the first charge and the second charge;

calculating the depth value corresponding to the first pixel based on the first TOF value when the first TOF value is equal to or less than a pulse width of the first emission ray and a pulse width of the second emission ray;

calculating a second TOF value based on the first charge and the second charge; and

calculating the depth value corresponding to the first pixel based on the second TOF value, when the first TOF value is greater than any one of the pulse width of the first emission ray and the pulse width of the second emission ray.

20. A computer-readable recording medium having stored thereon instructions for causing a computer to implement a method of obtaining a depth image, the instructions comprising:

emitting a first emission ray and a second emission ray;

measuring charges respectively generated by a reflection ray of the first emission ray and a reflection ray of the second emission ray.

21. The computer-readable recording medium of claim 20, wherein a pulse width of the first emission ray is different from a pulse width of the second emission ray.

22. The computer-readable recording medium of claim 20, wherein the measuring comprises:

measuring a first charge of the charges based on a first control signal which is in-phase with the first emission ray; and

measuring a second charge of the charges based on a second control signal having a first phase difference with the first emission ray.

23. The computer-readable recording medium of claim 22, further comprising:

calculating a depth value corresponding to a first pixel based on the first charge and the second charge.

24. The computer-readable recording medium of claim 23, wherein the depth value corresponding to a first pixel=c*(1.5*TOT*Q₂/(Q₁+Q₂))/2, when the first TOF value is equal to or less than a pulse width of the first emission ray and a pulse width of the second emission ray, and the depth value corresponding to a first pixel=c*(TOT*(2Q₂−

Q₁)/(Q₁+Q₂))/2, when the first TOF value is greater than any one of the pulse width of the first emission ray and the pulse width of the second emission ray, c being the speed of light constant, TOT being the pulse width of the second emission ray, Q1 being the first charge, and Q2 being the second charge.

25. The computer-readable recording medium of claim 23, wherein the calculating comprises:

calculating a first TOF value based on the first charge and the second charge;

calculating the depth value corresponding to the first pixel based on the first TOF value when the first TOF value is equal to or less than a pulse width of the first emission ray and a pulse width of the second emission ray;

calculating a second TOF value based on the first charge and the second charge; and

calculating the depth value corresponding to the first pixel based on the second TOF value, when the first TOF value is greater than any one of the pulse width of the first emission ray and the pulse width of the second emission ray.