# US 10,481,263 B2 · Range finding apparatus, moveable apparatus, robot, three dimensional measurement apparatus, method of measuring three dimensional information, and storage medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,481,263 B2 - Document ID: US10481263B2 - Status: Granted - Kind: B2 - Application number: 15/447,973 - Filed: 2017-03-02 - Published: 2017-09-14 - Granted: 2019-11-19 - Earliest claimed: 2016-03-10 - Assignees: Ricoh Company, Ltd. - Applicants: Ricoh Company, Ltd. - Inventors: Shu Takahashi; Yasuhiro Nihei; Masahiro Itoh; Takeshi Ogawa; Hiroaki Tanaka; Yoichi Ichikawa; Koji Masuda - Web page: https://patentgrep.com/patent/US10481263B2 ## CPC - G01S 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) - G01S 7/4915: Time delay measurement, e.g. operational details for pixel components (signal extraction and conditioning G01S7/493); Phase measurement - G01S 17/36: with phase comparison between the received signal and the contemporaneously transmitted signal - G01S 17/894: Three-dimensional [3D] imaging with simultaneous measurement of time-of-flight at a two-dimensional [2D] array of receiver pixels, e.g. time-of-flight cameras or flash lidar - 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 A range finding apparatus includes a light emission unit including a light source and a light source driver, a light detection unit, and circuitry. The light source driver supplies a plurality of drive pulses having different pulse width at different time periods. The light detection unit receives the light emitted from the light emission unit and then reflected from an object. The circuitry calculates a range to the object based on a time difference between one time point when a pulse light is emitted from the light source and another time point when light reflected from the object is received by the light detection unit. One of the drive pulses set with a smaller pulse width is set with a sine wave pattern, and another one of the drive pulses set with a greater pulse width is set with a rectangular wave pattern. ## Claims ### Claim 1 A range finding apparatus comprising: a light emitter including a light source and a light source driver, the light source driver to supply a plurality of drive pulses including a first drive pulse having a first pulse width to the light source at a first time period, and a second drive pulse having a second pulse width to the light source at a second time period, the first pulse width and the second pulse width being different with each other, and the first time period and the second time period being different with each other; a light detector to receive the light emitted from the light emitter and then reflected from an object; and circuitry to calculate a range to the object based on a time difference between one time point when a pulse light is emitted from the light source and another time point when light reflected from the object is received by the light detector, wherein when the first pulse width is set smaller than the second pulse width, the first drive pulse is set with a sine wave pattern and the second drive pulse is set with a rectangular wave pattern, and when the second pulse width is set smaller than the first pulse width, the first drive pulse is set with a rectangular wave pattern and the second drive pulse is set with a sine wave pattern. ### Claim 2 (depends on 1) The range finding apparatus of claim 1, wherein the light detector includes an image capturing device that receives the light reflected from the object, and converts the light reflected from the object to an electrical signal, divides the electrical signal into a plurality of signals temporally, and allocates each of the plurality of signals to a corresponding time period, wherein the circuitry calculates a time difference based on the plurality of signals, calculates the range to the object based on the time difference, and acquires three dimensional information of the object based on the calculated range to the object, wherein the circuitry calculates a first range to the object calculated from the time difference, calculated during the first time period when the first drive pulse is being supplied to the light source, and a second range to the object calculated from the time difference, calculated during the second time period when the second drive pulse is being supplied to the light source to acquire the three dimensional information of the object. ### Claim 3 (depends on 2) The range finding apparatus of claim 2, wherein when a temporal division number of the electrical signal is referred to Na (Na ≥3), each of the divided electrical signals is referred to Ci (1≤i≤Na), I=Σ{Ci×sin{(2π/Na)×(i−1))}(1≤i≤Na), Q=Σ{Ci×cos{(2π/Na)×(i−1)}(1≤i≤Na),φ=arctan(I/Q), the first pulse width of the first drive pulse is referred to T0, and the time difference is referred to Td for the first time period, Td=φ/2π×2T0 is established. ### Claim 4 (depends on 2) The range finding apparatus of claim 2, wherein, in the second time period, when a temporal division number of the electrical signal is referred to Nb (Nb≥2), each of the divided electrical signals is referred to Di (1≤i≤Nb), the time difference is referred to Td', the second pulse width T1 of the second drive pulse is divided into a signal Di and a signal Di+1, which are adjacent electrical signals, Td′={Di+1/(Di+1)}×T1 is established. ### Claim 5 (depends on 2) The range finding apparatus of claim 2, wherein the image capturing device includes one light reception element that receives the light reflected from the object and converts the light into charges, and a plurality of charge accumulators to accumulate the charges, the number of the plurality of charge accumulators is “N” indicating two or more. ### Claim 6 (depends on 5) The range finding apparatus of claim 5, wherein the temporal division number of the electrical signal is “N” or less for the second time period. ### Claim 7 (depends on 5) The range finding apparatus of claim 5, wherein when “N” is two (N=2), the circuitry detects intensity of ambient light based on luminance information acquired from the image capturing device during the first time period, and removes an ambient light component from the luminance information, acquired by the image capturing device, during the second time period. ### Claim 8 (depends on 1) The range finding apparatus of claim 1, wherein the first drive pulse having the first pulse width is supplied to the light source by setting a first time period, the second drive pulse having the second pulse width is supplied to the light source by setting a second time period, and a time length of the first time period and a time length of the second time period are set differently. ### Claim 9 (depends on 1) The range finding apparatus of claim 1, wherein the first drive pulse is set with a first frequency, and the second drive pulse is set with a second frequency different from the first frequency. ### Claim 10 (depends on 1) The range finding apparatus of claim 1, wherein the first drive pulse is set with a first frequency, and the second drive pulse is set with a second frequency that is the same as the first frequency. ### Claim 11 (depends on 1) A moveable apparatus comprising: the range finding apparatus of claim 1, wherein the moveable apparatus moves autonomously based on an output result of the range finding apparatus. ### Claim 12 (depends on 1) A robot comprising: the range finding apparatus of claim 1, wherein the robot moves autonomously based on an output result of the range finding apparatus. ### Claim 13 (depends on 1) A three dimensional measurement apparatus comprising: the range finding apparatus of claim 1. ### Claim 14 A method of measuring three dimensional information of an object, comprising: supplying a first drive pulse having a first pulse width to a light source to emit a first light from the light source; receiving the first light, emitted from the light source and reflected from an object, by a light detector; supplying a second drive pulse having a second pulse width, different from the first pulse width of the first drive pulse, to the light source to emit a second light from the light source; receiving the second light, emitted from the light source and reflected from the object by the light detector; and calculating three dimensional information of the object based on a reception result of the first light by the light detector and a reception result of the second light by the light detector, wherein when the first pulse width is set smaller than the second pulse width, the first drive pulse is set with a sine wave pattern and the second drive pulse is set with a rectangular wave pattern, and when the second pulse width is set smaller than the first pulse width, the first drive pulse is set with a rectangular wave pattern and the second drive pulse is set with a sine wave pattern. ### Claim 15 A non-transitory storage medium storing a program that, when executed by a computer, causes the computer to execute a method of measuring three dimensional information of an object, the method comprising: supplying a first drive pulse having a first pulse width to a light source to emit a first light from the light source; receiving the first light, emitted from the light source and reflected from an object, by a light detector; supplying a second drive pulse having a second pulse width, different from the first pulse width of the first drive pulse, to the light source to emit a second light from the light source; receiving the second light, emitted from the light source and reflected from the object by the light detector; and calculating three dimensional information of the object based on a reception result of the first light by the light detector and a reception result of the second light by the light detector, wherein when the first pulse width is set smaller than the second pulse width, the first drive pulse is set with a sine wave pattern and the second drive pulse is set with a rectangular wave pattern, and when the second pulse width is set smaller than the first pulse width, the first drive pulse is set with a rectangular wave pattern and the second drive pulse is set with a sine wave pattern. ### Claim 16 (depends on 1) The range finding apparatus according to claim 1, wherein the light source is a light emitting diode. ### Claim 17 (depends on 1) The range finding apparatus according to claim 1, wherein the light source is a semiconductor laser. ### Claim 18 (depends on 17) The range finding apparatus according to claim 17, wherein the semiconductor laser is an edge-emitting laser. ### Claim 19 (depends on 17) The range finding apparatus according to claim 17, wherein the semiconductor laser is a surface-emitting laser.