Dual mode depth imaging

• US 7,852,461 B2
• Filed: 11/15/2007
• Issued: 12/14/2010
• Est. Priority Date: 11/15/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft International Holdings BV (Microsoft Corporation)
• Inventors: Yahav, Giora
• Primary Examiner(s): Tarcza; Thomas H
• Assistant Examiner(s): Ratcliffe; Luke D
• Application Number:
  US11/984,250
• Publication Number:
  US 20090128833A1
• Time in Patent Office: 1,125 Days
• Field of Search: 356 301- 285
• US Class Current: 356/3.08
• CPC Class Codes: G01S 17/48 Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/87 Combinations of systems using electromagnetic waves other than radio waves
• 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: H04N 13/207 using a single 2D image sensor
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects

Abstract

Dual mode depth imaging system and method is provided, the system comprising a first and second image sensors and a processor able to switch between a first mode of depth imaging and a second mode of depth imaging according to at least one predefined threshold. The method comprising providing depth sensing by Time of Flight if the distance of the sensed object from the camera is not below a first threshold and/or if a depth resolution above a second threshold is not required, and providing depth sensing by triangulation, if the distance of the sensed object from the camera is below the first threshold and/or if a depth resolution above the second threshold is required.

Claims

1. A system for dual mode depth imaging, the system comprising:

a first and second image sensors; and

a processor able to determine if a distance of a sensed object from said system is below a first threshold, wherein said first threshold is derived based on a dynamic depth sensing range associated with a first mode of depth imaging and a second mode of depth imaging;

determine if a depth resolution above a second threshold is required by an application; and

automatically switch between said first mode of depth imaging and said second mode of depth imaging in real time according to the first threshold, the depth resolution and the second threshold.

2. A system according to claim 1, wherein said processor is to activate said first and second image sensors in said first mode of depth imaging when the distance of the sensed object from said system is below said first threshold, and to activate said first and second image sensors in said second mode of depth imaging when the distance of said sensed object from said system is above said first threshold.

3. A system according to claim 1, wherein said first image sensor is to provide said second mode of depth imaging according to Time-of-Flight of pulsed radiation reflected from an imaged object.

4. A system according to claim 1, wherein said second image sensor is to sense color of an imaged object.

5. A system according to claim 1, wherein said first mode of depth imaging includes calculation of distances by triangulation based on geometrical parameters derived from at least one of the first and second image sensors.

6. A system according to claim 1, wherein said second mode of depth imaging includes calculation of distances according to Time-of-Flight of pulsed radiation reflected from an imaged object.

7. A system according to claim 1, wherein said processor is further to activate said first and second image sensors in said first mode of depth imaging when said depth resolution above said second threshold is required.

8. A system according to claim 1, wherein said first image sensor is black and white sensor.

9. A system according to claim 2, wherein the value of said first threshold is approximately several tens of centimeters.

10. A system according to claim 1, wherein said processor is to switch between said first mode of depth imaging and said second mode of depth imaging when the distance of the sensed object from said system exceeds said first threshold, and to switch between said second mode of depth imaging and said first mode of depth imaging when the distance of the sensed object from said system decreases below said first threshold.

11. A system according to claim 1, wherein the dynamic depth sensing range of said first mode of depth imaging is substantially from a few centimeters to several tens of centimeters.

12. A system according to claim 1, wherein the dynamic depth sensing range of said second mode of depth imaging is substantially from several tens of centimeters to a few meters.

13. A system according to claim 6, further including a radiation source.

14. A system according to claim 5, wherein said processor is further to match the images received from the first and second image sensors.

15. A method for dual mode depth imaging, the method comprising:

checking distance of a sensed object from a camera to conclude whether said distance is below a first threshold, wherein said distance is derived based on a dynamic depth sensing range associated with depth sensing by Time of Flight and depth sensing by triangulation;

checking whether a depth resolution above a second threshold is required by an application;

automatically switching between said depth sensing by Time of Flight and said depth sensing by triangulation in real time based on the first threshold, the second threshold and the depth resolution, said automatically switching comprising;

providing said depth sensing by Time of Flight, if the distance of the sensed object from the camera is not below said first threshold and if the depth resolution above a second threshold is not required; and

providing said depth sensing by triangulation, if the distance of the sensed object from the camera is below said first threshold and if the depth resolution above the second threshold is required.

16. One or more processor readable storage devices having processor readable code embodied on said one or more processor readable storage devices, the processor readable code for programming one or more processors to perform a method comprising:

checking distance of a sensed object from a camera to conclude whether said distance is below a first threshold, wherein said distance is derived based on a dynamic depth sensing range associated with a first mode of depth imaging and a second mode of depth imaging;

checking whether a depth resolution above a second threshold is required by an application;

automatically switching between said first mode of depth imaging and said second mode of depth imaging in real time based on the first threshold, the second threshold and the depth resolution, said automatically switching comprising;

providing said depth sensing by said first mode of imaging, if the distance of the sensed object from the camera is not below said first threshold and if the depth resolution above a second threshold is not required; and

providing said depth sensing by said second mode of imaging, if the distance of the sensed object from the camera is below said first threshold and if the depth resolution above the second threshold is required.