CMOS-compatible three-dimensional image sensing using reduced peak energy
US6587186B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 2001 |
| Grant date | Jul 1, 2003 |
| Priority date | — |
| Expiry date | Jun 6, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/87
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A three-dimensional time-of-flight (TOF) system includes a low power optical emitter whose idealized output S1=cos(&ohgr;·t) is reflected by a target distance z away as S2=A·cos(&ohgr;·t+&PHgr;), for detection by a two-dimensional array of pixel detectors and associated narrow bandwidth detector electronics and processing circuitry preferably fabricated on a common CMOS IC. Phase shift &PHgr; is proportional to TOF or z, z=&PHgr;·C/2·&ohgr;=&PHgr;·C/{2·(2·&pgr;·f)}, and A is brightness. &PHgr;, z, and A are determined by homodyne-mixing S2 with an internally generated phase-delayed version of S1, whose phase is dynamically forced to match the phase of S2 by closed-loop feedback. Idealized mixer output per each pixel detector is 0.5·A·{cos(2&ohgr;·t+&PHgr;)+cos(&PHgr;)}. On-chip circuitry can use TOE data to simultaneously measure distance, object point velocity, object contours, including user interface with virtual input devices.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.