Surface distance determination using reflected light
First Claim
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; and
determine 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.
2 Assignments
0 Petitions
Accused Products
Abstract
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.
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Citations
20 Claims
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1. A system comprising:
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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, and a 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; and determine 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method comprising:
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emitting light in pulses; measuring, via a sensor device, an intensity of a pulse of light after the pulse of light is reflected off a surface of an object, the measuring providing a first measured intensity value of light associated with a first interval and a second measured intensity value of light associated with a second interval; comparing the first measured intensity value of light to the second measured intensity value of light; determining a variance of at least the first measured intensity value of light and a prior measured intensity value of light; comparing 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 frequency; selecting the distance range to indicate candidate distances for a distance between the sensor device and the surface; and determining the distance based at least in part on the comparing the first measured intensity value of light to the second measured intensity value of light and the distance range, the distance being within the distance range. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method comprising:
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emitting light in pulses; measuring, using a sensor device, an intensity of a pulse of light after the pulse of light is reflected off a surface of an object, the measuring providing a first measured intensity value of light associated with a first interval and a second measured intensity value of light associated with a second interval; measuring an intensity of a second pulse of light after the second pulse of light is reflected off the surface of the object, the measuring providing a third measured intensity value of light associated with the first interval and a fourth measured intensity value of light associated with the second interval; performing a comparison between the first measured intensity value of light and the second measured intensity value of light; determining a variance of at least the first measured intensity value of light and the third measured intensity value of light or from at least the second measured intensity value of light and the fourth measured intensity value of light; comparing 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 frequency; selecting the distance range to indicate candidate distances for a distance between the sensor device and the surface; and determining the distance based at least in part on the comparison between the first measured intensity value of light and the second measured intensity value of light, the distance being within the distance range. - View Dependent Claims (17, 18, 19, 20)
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Specification