Time-of-flight independent of object reflectivity
AssigneeSensors Unlimited, Inc.
InventorThuc-Uyen Nguyen
Life of this patent
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Abstract
A method includes flashing an object with a first illumination pulse at a first illumination power level, flashing the object with a second illumination pulse at a second illumination power level different from the first illumination power level, integrating at least a portion of a first return pulse which is the first illumination plus returning from the object to determine a first return time, and integrating at least a portion of a second return pulse which is the second illumination pulse returning from the object to determine a second return time. The method includes using the first and second return times to determine distance to the object independent of reflectivity of the object.
Claims13
A method comprising:
- flashing an object with a first illumination pulse at a first illumination power level;
- flashing the object with a second illumination pulse at a second illumination power level different from the first illumination power level;
- integrating at least a portion of a first return pulse which is the first illumination pulse returning from the object to determine a first return time;
- integrating at least a portion of a second return pulse which is the second illumination pulse returning from the object to determine a second return time;
- and
- using the first and second return times to determine distance to the object independent of reflectivity of the object;
- wherein using the first and second return times to determine the distance to the object includes using a look up table (LUT) to correlate the first and second return times to distance to the object, wherein the first and second return times are input to the LUT and wherein actual travel time and/or distance to the object is output from the LUT.
A system comprising:
- an illuminator configured to flash a scene with two different levels of illumination power;
- a sensor that is sensitive to illumination from the illuminator;
- and
- a controller operatively connected to the illuminator and to the sensor, the controller being configured to use the sensor and the illuminator at two different levels of illumination power to find range to an object independent of reflectivity of the object;
- wherein the controller includes machine readable instructions configured to cause the controller to:
- use the illuminator to flash an object with a first illumination pulse at a first illumination power level;
- use the illuminator to flash the object with a second illumination pulse at a second illumination power level lower than the first illumination power level;
- use the sensor to integrate at least a portion of a first return pulse which is the first illumination plus returning from the object to determine a first return time;
- use the sensor to integrate at least a portion of a second return pulse which is the second illumination pulse returning from the object to determine a second return time;
- and
- use the first and second return times to determine distance to the object independent of reflectivity of the object, wherein using the first and second return times to determine the distance to the object includes using a look up table (LUT) to correlate the first and second return times to distance to the object, wherein the first and second return times are input to the LUT and wherein actual travel time and/or distance to the object is output from the LUT.
Dependencies are inferred from the claim text.