Methods and apparatus for time-of-flight imaging
US10191154B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 13, 2017 |
| Grant date | Jan 29, 2019 |
| Priority date | — |
| Expiry date | Feb 13, 2037 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S17/894
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In some implementations, scene depth is extracted from dual frequency of a cross-correlation signal. A camera may illuminate a scene with amplitude-modulated light, sweeping the modulation frequency. For each modulation frequency in the sweep, each camera pixel may measure a cross-correlation of incident light and of a reference electrical signal. Each pixel may output a vector of cross-correlation measurements acquired by the pixel during a sweep. A computer may perform an FFT on this vector, identify a dual frequency at the second largest peak in the resulting power spectrum, and calculate scene depth as equal to a fraction, where the numerator is the speed of light times this dual frequency and the denominator is four times pi. In some cases, the two signals being cross-correlated have the same phase as each other during each cross-correlation measurement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.