# US 2010/0165322 A1 · Camera-style lidar setup > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0165322 A1 - Document ID: US20100165322A1 - Status: Published application - Kind: A1 - Application number: 12/317,771 - Filed: 2008-12-29 - Published: 2010-07-01 - Earliest claimed: 2008-12-29 - Assignees: Arete Associates - Inventors: David M. Kane; Jeff T. Daiker; James T. Murray - Web page: https://patentgrep.com/patent/US20100165322A1 ## CPC - G01S 17/42: Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S17/46) - G01S 7/481: Constructional features, e.g. arrangements of optical elements - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract Separate reception/transmission apertures enhance pointing: reception is more efficient than transmission (kept smaller for MEMS steering). Apparatus aspects of the invention include lidar transmitters emitting laser beams, and scan mirrors (or assemblies) angularly adjustable to deflect the beams in orthogonal directions. In one aspect, afocal optics magnify deflection; a transmitter aperture transmits the beam; a lidar receiver doesn't share the transmitter aperture. In another aspect, auxiliary optics calibrate the deflection. A method aspect of the invention notices and responds to a remote source—using a similar local laser, adjustable scan mirror or assembly, afocal deflection magnifier, transmission aperture and separate receiver. Method steps include operating the receiver to notice and determine location of the remote source; and controlling the transmitter to direct laser light back toward that location. Among preferences: receiver aperture exceeds five times transmitter aperture; receiver is segmented; beam expander between laser and mirror(s) controls waist or divergence, for selecting Gaussian or Rayleigh divergence and “zoom”. ## Claims ### Claim 1 A lidar apparatus comprising: a lidar transmitter that includes a laser source that produces a laser beam, a scan mirror or scan-mirror assembly angularly adjustable to deflect the beam in at least two orthogonal directions, and an afocal optical unit for magnifying the beam deflection; said transmitter having an aperture for transmitting the beam; and a lidar receiver that does not share the transmitter aperture; wherein: the receiver comprises plural separate discrete receiver modules, each having an aperture whose area is individually smaller than the area of the transmitter aperture, and each being either: a CCD array, or an individual photodetector not integrated with other photodetectors into an array; and aggregate aperture area of the plural receiver modules is larger than the area of the transmitter aperture. ### Claim 2 (depends on 1) The apparatus of claim 1, further comprising: a beam expander, disposed between the laser and the mirror or mirrors, for controlling the beam waist or divergence, or both, particularly at the mirror or mirrors; and wherein: means for effectively providing a “zoom” function; wherein the effectively-providing means in turn comprise: means for causing the expander to be adjustable, and means, controlled by adjusting the expander, for enabling selection of Gaussian or Rayleigh divergence. ### Claim 3 (depends on 1) The apparatus of claim 1, further comprising: an auxiliary optical system for calibrating the deflection produced by the mirror or mirror assembly; wherein: the laser beam follows a particular optical path at the mirror or mirrors; and the auxiliary optical system comprises: means for causing an auxiliary radiation beam to follow, at the mirror or mirrors, an optical path identical or similar to the particular path, and means for monitoring deflection of the auxiliary beam by the mirror or mirrors; and the causing means comprise a beamsplitter for at least roughly aligning the auxiliary beam with the laser beam in approaching the mirror or mirrors. ### Claim 4 (depends on 3) The apparatus of claim 3, further comprising: means for separating the auxiliary beam from the laser beam after leaving the mirror or mirrors; an auxiliary detector for determining deflection of the separated auxiliary beam by the mirror or mirrors; and means for correlating the determined deflection with control signals that operate the mirror or mirrors; and wherein: the separating means comprise means for passing the auxiliary beam through the same beamsplitter again or through another beamsplitter. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein: the auxiliary detector is a position-sensing detector (“PSD”). ### Claim 6 (depends on 3) The apparatus of claim 3, wherein: the beamsplitter is wavelength sensitive; and the auxiliary beam and laser beam are of different wavelengths; and the beamsplitter is a dichroic element or holographic element. ### Claim 7 (depends on 3) The apparatus of claim 3, further comprising: means for at least roughly synchronizing pulses of the laser beam with sensitive times or dispositions, or both, of the receiver. ### Claim 8 (depends on 1) The apparatus of claim 1, further comprising one or both of: calculating means for determining time delay between transmission of a pulse of the laser beam and receipt of a reflected return of the pulse from an object; and comparison means for determining Doppler shift in the laser beam; and wherein the calculating or comparison means further comprise, respectively: means for calculating object distance from the determined time delay, or means for deriving relative speed from the shift; and further comprising means for incorporating information about the apparatus orientation or location, or both, together with information that the apparatus has noticed a return from an object, or distance of such an object, or both. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein: the receiver has a detector of particular overall dimensions, and is controlled actively to select operation as either: a single unit having said particular overall dimensions, or multiple subsections of the detector, each having dimensions smaller than said particular overall dimensions; and a sampled region is selected based on knowledge of where the scan mirror is pointing the laser beam, to facilitate sampling of smaller units. ### Claim 10 (depends on 1) The apparatus of claim 1, further comprising: means for measuring the angles of beam deflection by the scan mirror or mirror assembly; said measuring means comprising a capacitive sensor responsive to an individual mirror or mirrors. ### Claim 11 (depends on 1) The apparatus of claim 1, further comprising: means for measuring the angles of beam deflection by the scan mirror or mirror assembly; said measuring means comprising a magnetic sensor responsive to an individual mirror or mirrors. ### Claim 12 (depends on 1) The apparatus of claim 1, further comprising: means for measuring the angles of beam deflection by the scan mirror or mirror assembly; said measuring means comprising a lookup table calibrated in drive voltage or current supplied to an individual mirror or mirrors. ### Claim 13 A method for noticing and responding to a remote light source, said method utilizing a transmitter which includes a local radiation source that produces a laser beam, a scan mirror or scan-mirror assembly angularly adjustable to deflect the beam in at least two orthogonal directions, and an afocal optical unit for magnifying the beam deflection, said transmitter having an aperture for transmitting the beam; and a radiation receiver that does not share the transmitter aperture; said method comprising the steps of: operating the receiver to notice and determine a location of the remote source; and controlling the transmitter to direct the laser beam back toward the determined location. ### Claim 14 (depends on 13) The method of claim 13, further comprising the step of: activating the receiver to collect and interpret reflected radiation of the back-directed laser beam, received from the location. ### Claim 15 (depends on 13) The method of claim 13, further utilizing an additional receiver; and further comprising the steps of: activating the additional receiver to collect and interpret reflected radiation of the back-directed laser beam, received from the location. ### Claim 16 (depends on 15) The method of claim 15, wherein: the first-mentioned receiver and the additional receiver are sensitive in respective different wavelength bands, namely: a first spectral waveband encompassing emissions of expected remote sources including but not necessarily limited to said remote light source; and a second spectral waveband encompassing said laser beam. ### Claim 17 (depends on 15) The method of claim 15, wherein: the activating step comprises using the additional receiver in a lidar operating mode to determine return time of the laser beam and thereby distance of a reflecting object at the location. ### Claim 18 (depends on 13) The method of claim 13, wherein the operating step comprises: fitting the centroid of an incoming radiation pattern to an expected shape, when the laser-beam divergence exceeds the per-pixel FOV.