# US 12,761,328 B2 · Distance measuring device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,761,328 B2 - Document ID: US12761328B2 - Status: Granted - Kind: B2 - Application number: 17/662,828 - Filed: 2022-05-10 - Published: 2022-08-25 - Granted: 2026-10-13 - Earliest claimed: 2019-11-12 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Kenta Azuma - Web page: https://patentgrep.com/patent/US12761328B2 ## CPC - G01S 7/4865: Time delay measurement, e.g. time-of-flight measurement, time of arrival measurement or determining the exact position of a peak (peak detection in noise, signal conditioning G01S7/487) - G01S 7/4876: {by removing unwanted signals (G01S7/495 takes precedence)} - G01S 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) - G01S 17/931: of land vehicles - 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 distance measuring device includes a light emitting unit, a light receiving array unit, a signal intensity calculation unit, a signal time calculation unit, an intensity correction unit, and a distance calculation unit. The light emitting unit emits pulsed signal light. The light receiving array unit includes a plurality of photodetectors, each of which outputs a pulse signal in response to incidence of a photon. The signal intensity calculation unit calculates a signal intensity that indicates a light intensity of the signal light received by the light receiving array unit. The signal time calculation unit calculates a rise time and a fall time of the signal light detected by the light receiving array unit. The intensity correction unit corrects at least one of the rise time and the fall time calculated by the signal time calculation unit based on the signal intensity calculated by the signal intensity calculation unit. ## Claims ### Claim 1 A distance measuring device comprising: a light emitting unit configured to emit pulsed signal light; a light receiving array unit including a plurality of photodetectors, each of which is configured to output a pulse signal in response to incidence of a photon; a signal intensity calculation unit configured to calculate a signal intensity that indicates a light intensity of the signal light received by the light receiving array unit; a signal time calculation unit configured to calculate a rise time and a fall time of the signal light detected by the light receiving array unit; an intensity correction unit configured to correct at least one of the rise time and the fall time calculated by the signal time calculation unit based on the signal intensity calculated by the signal intensity calculation unit; a distance calculation unit configured to, in response to the rise time being corrected, calculate an object distance that is a distance to an object that reflected the signal light, based on at least the corrected rise time, and in response to the fall time being corrected, calculate the object distance based on at least the corrected fall time; a pulse width calculation unit configured to calculate a pulse width of the signal light based on the corrected rise time and the corrected fall time; and a pulse width determination unit configured to determine whether the pulse width calculated by the pulse width calculation unit is greater than or equal to a preset calculation criterion value, wherein the distance calculation unit is configured to switch between a plurality of methods of calculating the object distance according to a result of determination by the pulse width determination unit. ### Claim 2 (depends on 1) The distance measuring device according to claim 1, further comprising: a temperature detection unit configured to detect a temperature of the light receiving array unit, wherein the intensity correction unit is further configured to correct at least one of the rise time and the fall time based on the temperature detected by the temperature detection unit. ### Claim 3 (depends on 1) The distance measuring device according to claim 1, further comprising: a noise intensity calculation unit configured to calculate a noise intensity that indicates a light intensity of light detected by the light receiving array unit while the signal light is not received by the light receiving array unit, wherein the intensity correction unit is further configured to correct at least one of the rise time and the fall time based on the noise intensity calculated by the noise intensity calculation unit. ### Claim 4 (depends on 3) The distance measuring device according to claim 3, further comprising: a histogram generation unit configured to generate, according to a plurality of the pulse signals output from the light receiving array unit, a histogram that indicates time variations in light intensity of light detected by the light receiving array unit, the histogram starting from an emission timing of the signal light emitted by the light emitting unit, wherein the noise intensity calculation unit is configured to calculate the noise intensity based on the histogram generated by the histogram generation unit. ### Claim 5 (depends on 3) The distance measuring device according to claim 3, further comprising: a histogram generation unit configured to generate, according to a plurality of the pulse signals output from the light receiving array unit, a histogram that indicates time variations in light intensity of light detected by the light receiving array unit, the histogram starting from an emission timing of the signal light emitted by the light emitting unit, wherein the signal intensity calculation unit is configured to calculate the signal intensity based on the histogram generated by the histogram generation unit, and the noise intensity calculation unit is configured to calculate the noise intensity based on the histogram generated by the histogram generation unit. ### Claim 6 (depends on 3) The distance measuring device according to claim 3, wherein the intensity correction unit is configured to correct at least one of the rise time and the fall time calculated by the signal time calculation unit according to an equation representing a correspondence relationship between the noise intensity calculated by the noise intensity calculation unit and an amount of correction of the at least one of the rise time and the fall time. ### Claim 7 (depends on 1) The distance measuring device according to claim 1, further comprising: a histogram generation unit configured to generate, according to a plurality of the pulse signals output from the light receiving array unit, a histogram that indicates time variations in light intensity of light detected by the light receiving array unit, the histogram starting from an emission timing of the signal light emitted by the light emitting unit, wherein the signal intensity calculation unit is configured to calculate the signal intensity based on the histogram generated by the histogram generation unit. ### Claim 8 (depends on 1) The distance measuring device according to claim 1, wherein the distance calculation unit is configured to, in response to the pulse width determination unit determining that the pulse width is less than the calculation criterion value, calculate the object distance using both the corrected rise time and the corrected fall time, and in response to the pulse width determination unit determining that the pulse width is greater than or equal to the calculation criterion value, calculate the object distance using only the corrected rise time among the corrected rise time and the corrected fall time. ### Claim 9 (depends on 1) The distance measuring device according to claim 1, wherein the intensity correction unit is configured to correct, with reference to a correction map, the at least one of the rise time and the fall time calculated by the signal time calculation unit based on the signal intensity calculated by the signal intensity calculation unit. ### Claim 10 (depends on 1) The distance measuring device according to claim 1, wherein the intensity correction unit is configured to correct at least one of the rise time and the fall time calculated by the signal time calculation unit according to an equation representing a correspondence relationship between the signal intensity calculated by the signal intensity calculation unit and an amount of correction of the at least one of the rise time and the fall time. ### Claim 11 A distance measuring device comprising: a light emitting unit configured to emit pulsed signal light; a light receiving array unit including a plurality of photodetectors, each of which is configured to output a pulse signal in response to incidence of a photon; a temperature detection unit configured to detect a temperature of the light receiving array unit; a signal time calculation unit configured to calculate a rise time and a fall time of the signal light detected by the light receiving array unit; a temperature correction unit configured to correct at least one of the rise time and the fall time calculated by the signal time calculation unit based on the temperature detected by the temperature detection unit; a distance calculation unit configured to, in response to the rise time being corrected, calculate an object distance that is a distance to an object that reflected the signal light, based on at least the corrected rise time, and in response to the fall time being corrected, calculate the object distance based on at least the corrected fall time; a pulse width calculation unit configured to calculate a pulse width of the signal light based on the corrected rise time and the corrected fall time; and a pulse width determination unit configured to determine whether the pulse width calculated by the pulse width calculation unit is greater than or equal to a preset calculation criterion value, wherein the distance calculation unit is configured to switch between a plurality of methods of calculating the object distance according to a result of determination by the pulse width determination unit. ### Claim 12 (depends on 11) The distance measuring device according to claim 11, further comprising: a signal intensity calculation unit configured to calculate a signal intensity that indicates a light intensity of the signal light received by the light receiving array unit; and a temperature correction unit is further configured to correct at least one of the rise time and the fall time based on the signal intensity calculated by the signal intensity calculation unit. ### Claim 13 (depends on 12) The distance measuring device according to claim 12, further comprising: a histogram generation unit configured to generate, according to a plurality of the pulse signals output from the light receiving array unit, a histogram that indicates time variations in light intensity of light detected by the light receiving array unit, the histogram starting from an emission timing of the signal light emitted by the light emitting unit, wherein the signal intensity calculation unit is configured to calculate the signal intensity based on the histogram generated by the histogram generation unit. ### Claim 14 (depends on 11) The distance measuring device according to claim 11, further comprising: a noise intensity calculation unit configured to calculate a noise intensity that indicates a light intensity of light detected by the light receiving array unit while the signal light is not received by the light receiving array unit; an intensity correction unit configured to correct at least one of the rise time and the fall time based on the noise intensity calculated by the noise intensity calculation unit. ### Claim 15 (depends on 14) The distance measuring device according to claim 14, further comprising: a histogram generation unit configured to generate, according to a plurality of the pulse signals output from the light receiving array unit, a histogram that indicates time variations in light intensity of light detected by the light receiving array unit, the histogram starting from an emission timing of the signal light emitted by the light emitting unit, wherein the noise intensity calculation unit is configured to calculate the noise intensity based on the histogram generated by the histogram generation unit. ### Claim 16 (depends on 14) The distance measuring device according to claim 14, wherein the temperature correction unit is configured to correct at least one of the rise time and the fall time calculated by the signal time calculation unit according to an equation representing a correspondence relationship between the noise intensity calculated by the noise intensity calculation unit and an amount of correction of the at least one of the rise time and the fall time. ### Claim 17 (depends on 11) The distance measuring device according to claim 11, further comprising: a signal intensity calculation unit configured to calculate a signal intensity that indicates a light intensity of the signal light received by the light receiving array unit; and a noise intensity calculation unit configured to calculate a noise intensity that indicates a light intensity of light detected by the light receiving array unit while the signal light is not received by the light receiving array unit, wherein the temperature correction unit is further configured to correct at least one of the rise time and the fall time based on the signal intensity calculated by the signal intensity calculation unit and the noise intensity calculated by the noise intensity calculation unit. ### Claim 18 (depends on 17) The distance measuring device according to claim 17, further comprising: a histogram generation unit configured to generate, according to a plurality of the pulse signals output from the light receiving array unit, a histogram that indicates time variations in light intensity of light detected by the light receiving array unit, the histogram starting from an emission timing of the signal light emitted by the light emitting unit, wherein the signal intensity calculation unit is configured to calculate the signal intensity based on the histogram generated by the histogram generation unit, and the noise intensity calculation unit is configured to calculate the noise intensity based on the histogram generated by the histogram generation unit. ### Claim 19 (depends on 11) The distance measuring device according to claim 11, wherein the distance calculation unit is configured to, in response to the pulse width determination unit determining that the pulse width is less than the calculation criterion value, calculate the object distance using both the corrected rise time and the corrected fall time, and in response to the pulse width determination unit determining that the pulse width is greater than or equal to the calculation criterion value, calculate the object distance using only the corrected rise time among the corrected rise time and the corrected fall time. ### Claim 20 (depends on 11) The distance measuring device according to claim 11, wherein the temperature correction unit is configured to correct, with reference to a correction map, at least one of the rise time and the fall time calculated by the signal time calculation unit based on the temperature detected by the temperature detection unit. ### Claim 21 (depends on 11) The distance measuring device according to claim 11, wherein the temperature correction unit is configured to correct at least one of the rise time and the fall time calculated by the signal time calculation unit based on the temperature detected by the temperature detection unit according to an equation representing a correspondence relationship between the temperature detected by the temperature detection unit and an amount of correction of the at least one of the rise time and the fall time.