Increasing measurement rate in time of flight measurement apparatuses
First Claim
1. A time of flight measurement apparatus comprising:
- one or more lasers each configured to transmit light;
an optical receiver configured to receive light;
laser control circuitry configured to cause the one or more lasers to transmit a first pulse of light prior to a second pulse of light, the laser control circuitry further configured to cause the one or more lasers to transmit the second pulse of light prior to a time at which a reflected portion of the first pulse of light is received by the optical receiver; and
elapsed time circuitry configured to measure an elapsed time between transmission of the first pulse of light by the laser and reception of the reflected portion of the first pulse of light by the optical receiver,wherein the first and second pulses of light are of the same frequency but are otherwise distinguishable when received by the apparatus.
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Accused Products
Abstract
An apparatus for measuring distance to a surface is disclosed. The apparatus transmits at least one subsequent pulse of light prior to receiving a reflection of a previously sent pulse of light. Thus, multiple pulses of light are in-flight at a given time. The embodiments are applicable to terrain mapping, bathymetry, seismology, detecting faults, biomass measurement, wind speed measurement, temperature calculation, traffic speed measurement, military target identification, surface to air rangefinding, high definition survey, close range photogrammetry, atmospheric composition, meteorology, distance measurement, as well as many other applications. Examples of such apparatuses include laser ranging systems, such as light detection and ranging (LIDAR) systems, and laser scanners. Data received from the apparatus by a data processing unit can be used to create a data model, such as a point cloud, digital surface model or digital terrain model describing the surface, terrain, and/or objects.
164 Citations
29 Claims
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1. A time of flight measurement apparatus comprising:
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one or more lasers each configured to transmit light; an optical receiver configured to receive light; laser control circuitry configured to cause the one or more lasers to transmit a first pulse of light prior to a second pulse of light, the laser control circuitry further configured to cause the one or more lasers to transmit the second pulse of light prior to a time at which a reflected portion of the first pulse of light is received by the optical receiver; and elapsed time circuitry configured to measure an elapsed time between transmission of the first pulse of light by the laser and reception of the reflected portion of the first pulse of light by the optical receiver, wherein the first and second pulses of light are of the same frequency but are otherwise distinguishable when received by the apparatus. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method performed by a LIDAR system including at least one laser for transmitting light and at least one receiver for receiving light reflected from a surface, the LIDAR system being configured for acquiring data describing the surface, the method comprising:
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transmitting a first pulse of light at a first scan angle; transmitting a second pulse of light after the first pulse of light is transmitted at a second scan angle that differs from the first scan angle; receiving a reflected portion of the first pulse of light after the second pulse of light is transmitted; and determining a time of flight of the first pulse of light by determining an elapsed time between the transmission of the first pulse of light and the time of reception of the reflected portion of the first pulse of light, wherein the first and second pulses of light are of the same frequency. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification