US 12,313,779 B2
Depth sensing using optical time-of-flight techniques through a transmissive cover
Pradeep Hegde, Frisco, TX (US); Timothy Cogan, McKinney, TX (US); Doug Nelson, Plano, TX (US); and Drew Paterson, Plano, TX (US)
Assigned to ams-Osram Asia Pacific Pte. Ltd., Singapore (SG)
Appl. No. 17/290,808
Filed by ams-Osram Asia Pacific Pte. Ltd., Singapore (SG)
PCT Filed Nov. 13, 2019, PCT No. PCT/SG2019/050560
§ 371(c)(1), (2) Date May 3, 2021,
PCT Pub. No. WO2020/101576, PCT Pub. Date May 22, 2020.
Claims priority of provisional application 62/768,273, filed on Nov. 16, 2018.
Prior Publication US 2021/0405158 A1, Dec. 30, 2021
Int. Cl. G01C 3/08 (2006.01); G01S 7/481 (2006.01); G01S 7/497 (2006.01); G01S 17/36 (2006.01); G01S 17/894 (2020.01)
CPC G01S 7/4813 (2013.01) [G01S 7/497 (2013.01); G01S 17/36 (2013.01); G01S 2007/4975 (2013.01); G01S 17/894 (2020.01)] 15 Claims
OG exemplary drawing
 
1. A method comprising:
emitting light from a module at a first modulation frequency and emitting light at a second modulation frequency, the light being emitted through a transmissive cover toward a target;
measuring first amplitude and phase shift values representing a combination of an optical signal reflected by the target and an optical signal reflected by the transmissive cover in response to the light emitted at the first modulation frequency;
measuring second amplitude and phase shift values representing a combination of an optical signal reflected by the target and an optical signal reflected by the transmissive cover in response to the light emitted at the second modulation frequency; and
estimating, using processing circuitry, an amplitude of an optical signal reflected by the transmissive cover and an amplitude of an optical signal reflected by the transmissive cover, the estimating being based, at least in part, on the measured first and second amplitude and phase shift values and on phase shift values obtained during calibration of the module, wherein estimating includes using an iterative process and/or using gradient descent.