Time of Flight Camera with Rectangular Field of Illumination

• US 20110025843A1
• Filed: 07/16/2010
• Published: 02/03/2011
• Est. Priority Date: 07/31/2009
• Status: Active Grant

• Current Assignee: Ams Sensors Singapore Pte. Ltd. (Ams-Osram AG)
• Original Assignee: MESA IMAGING AG (Ams-Osram AG)
• Inventors: Richter, Michael, Oggier, Thierry
• Granted Patent: US 8,803,967 B2
• Time in Patent Office: Days
• US Class Current: 348/135
• 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 17/931 of land vehicles
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G02B 19/0019 having reflective surfaces only (e.g. louvre systems, systems with multiple planar reflectors)
• CPC Class Codes: G02B 19/0052 the light source comprising a laser diode coupling into light guides using intermediate optical elements G02B6/4204; semiconductor lasers having optical devices external to the laser cavity H01S5/005
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 5/09 Multifaceted or polygonal mirrors , e.g. polygonal scanning mirrors; Fresnel mirrors
• CPC Class Codes: H04N 13/204 using stereoscopic image cameras stereoscopic photography G03B35/00
• CPC Class Codes: H04N 23/56 provided with illuminating means

Abstract

Improved field-of-illumination (FOI) and field-of-view (FOV) matching for 3D time-of-flight cameras is provided using light emitters with rectangular reflectors. A better adjustment of the FOI with the camera'"'"'s FOV has the following advantages: optimal use of emitted light and reduced multi-path problems. Furthermore, embodiments bring the benefit for rather low-cost customization of the illumination to match the FOI to the specified FOV.

Claims

1. A time of flight camera, comprising:

a time of flight detector chip for detecting light from a scene;

a light emitter for producing modulated light for illuminating the scene;

a frusto pyramidal reflector for directing light from the light emitter onto the scene.

2. A camera as claimed in claim 1, wherein the light emitter is a light emitting diode.

3. A camera as claimed in claim 1, wherein the light emitter is a laser diode.

4. A camera as claimed in claim 1, wherein the frusto pyramidal reflector is metal coated.

5. A camera as claimed in claim 1, wherein the frusto pyramidal reflector has a rectangular cross-section.

6. A camera as claimed in claim 1, wherein the time of flight detector chip includes an array of pixels that demodulate light returning from the scene synchronously with the modulation of the light emitter.

7. A camera as claimed in claim 1, further comprising a front cover, the frusto pyramidal reflector being formed in the front cover.

8. A camera as claimed in claim 1, further comprising optical elements to further shape the field of illumination.