Surface distance determination using reflected light

摘要

A distance between a light source and a surface may be determined by emitting pulses of light from the light source and measuring an intensity of the light after the light reaches the surface. To determine a true distance, aliased distances, which are outside of a known distance segment, are disregarded. The distance segment may be defined by a modulation period of light emitted by the light source. The distance segment may be determined based on a ratio of a measured intensity of light captured during a first time interval and a second time interval, and a comparison of other types of evidence data that identifies a correct distance segment. The evidence data may include data associated with the amplitude (intensity) of the light captured, temporal variations in data, and/or analysis data collected from other surfaces that are adjacent to the surface.

主权项

1. A system comprising:
a light source to emit pulses of light at a predetermined frequency; a sensor housing including at least two light sensors to detect light emitted from the light source and light reflected off of a surface of an object, the two light sensors including:
a first light sensor to measure an intensity of light detected during a first time interval and determine a first measured intensity value, anda second light sensor to measure an intensity of light detected during a second time interval, equal to the first time interval, and determine a second measured intensity value, wherein the first light sensor is off during the second time interval and the second light sensor is off during the first time interval; and one or more processors to:
determine a ratio of the first measured intensity value to the second measured intensity value;determine a variance of at least the ratio and a prior ratio determined from prior measured intensity values;compare the variance to baseline variance data that associates the variance with a distance range, the distance range including a minimum distance and a maximum distance defined by a distance of light travel during one cycle of the predetermined frequency;select the distance range to indicate candidate distances for a distance between the sensor housing and the surface; anddetermine the distance between the sensor housing and the surface based at least in part on the ratio and the candidate distances included in the distance range.