# US 11,906,669 B2 · Distance information acquisition device, multipath detection device, and multipath detection method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,669 B2 - Document ID: US11906669B2 - Status: Granted - Kind: B2 - Application number: 17/037,465 - Filed: 2020-09-29 - Published: 2021-01-14 - Granted: 2024-02-20 - Earliest claimed: 2018-03-29 - Assignees: Nuvoton Technology Corporation Japan - Applicants: Panasonic Semiconductor Solutions Co., Ltd. - Inventors: Megumi Nagata - Web page: https://patentgrep.com/patent/US11906669B2 ## CPC - G01S 7/487: Extracting wanted echo signals {, e.g. pulse detection} - 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 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 17/10: using transmission of interrupted, pulse-modulated waves (determination of distance by phase measurements G01S17/32) - G01S 17/89: for mapping or imaging - 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 information acquisition device includes: a light emitter which emits light according to an emission pulse indicating emission; a solid-state imaging element which performs exposure according to an exposure pulse indicating exposure; an emission/exposure controller which generates a timing signal indicating a plurality of pairs of the emission pulse and the exposure pulse having a time difference that is different in each of the plurality of pairs; and a multipath detector which obtains a sequence of received light signals from the solid-state imaging element by the emission and the exposure that correspond to each of the plurality of pairs, compares the obtained sequence of received light signals and reference data created in advance as a model of a sequence of received light signals in a multipath-free environment, and determines the presence or absence of multipath according to a difference in a comparison result. ## Claims ### Claim 1 A distance information acquisition device, comprising: a light emitter which emits light according to an emission pulse indicating emission; a solid-state imaging element which performs exposure according to an exposure pulse indicating exposure; an emission/exposure controller which generates a timing signal indicating a plurality of pairs of the emission pulse and the exposure pulse that have a time difference, the time difference being different in each of the plurality of pairs; and a multipath detector which obtains a sequence of received light signals from the solid-state imaging element by the emission and the exposure that correspond to each of the plurality of pairs, compares the sequence of received light signals that has been obtained and reference data created in advance as a model of a sequence of received light signals in a multipath-free environment, and determines a presence or absence of multipath according to a difference in a comparison result. ### Claim 2 (depends on 1) The distance information acquisition device according to claim 1, wherein a total number of the plurality of pairs is six or more. ### Claim 3 (depends on 1) The distance information acquisition device according to claim 1, wherein the time difference between the emission pulse and the exposure pulse in each of the plurality of pairs differs by a fixed amount of time. ### Claim 4 (depends on 1) The distance information acquisition device according to claim 1, wherein the emission/exposure controller changes a timing of the exposure pulse relative to a timing of the emission pulse in the plurality of pairs. ### Claim 5 (depends on 1) The distance information acquisition device according to claim 1, wherein the emission/exposure controller changes a timing of the emission pulse relative to a timing of the exposure pulse in the plurality of pairs. ### Claim 6 (depends on 1) The distance information acquisition device according to claim 1, wherein a width of the exposure pulse is greater than or equal to a width of the emission pulse. ### Claim 7 (depends on 1) The distance information acquisition device according to claim 1, wherein the plurality of pairs include first through N-th pairs, N being an integer, and the emission/exposure controller generates the timing signal to cause the first through N-th pairs to be produced on a time-series basis. ### Claim 8 (depends on 1) The distance information acquisition device according to claim 1, wherein the plurality of pairs include first through N-th pairs in ascending order of the time difference, N being an even number, and the emission/exposure controller generates the timing signal to alternately arrange one pair selected in the ascending order of the time difference and one pair selected in descending order of the time difference. ### Claim 9 (depends on 1) The distance information acquisition device according to claim 1, wherein the time difference between emission pulses in the plurality of pairs is a fixed amount of time. ### Claim 10 (depends on 1) The distance information acquisition device according to claim 1, wherein the plurality of pairs include first through N-th pairs, N being an integer greater than or equal to 6, the first through N-th pairs share one emission pulse, the first through N-th pairs respectively correspond to first through N-th pixels included in the solid-state imaging element, and the emission/exposure controller concurrently generates N timing signals indicating the exposure in the first through N-th pairs and supplies the N timing signals to the first through N-th pixels. ### Claim 11 (depends on 1) The distance information acquisition device according to claim 1, wherein the multipath detector includes a reference data holder which holds the reference data, and the reference data is a model of the sequence of received light signals in the multipath-free environment. ### Claim 12 (depends on 1) The distance information acquisition device according to claim 1, wherein the multipath detector includes a reference data holder which holds the reference data, and the reference data is a length of time determined according to a sum of a pulse width of the emission pulse and a pulse width of the exposure pulse. ### Claim 13 (depends on 1) The distance information acquisition device according to claim 1, wherein when the multipath detector determines that the multipath is present, the multipath detector further calculates a correction factor for each pixel. ### Claim 14 (depends on 13) The distance information acquisition device according to claim 13, wherein the multipath detector calculates the correction factor according to a comparison result indicating a ratio between the sequence of received light signals and the reference data. ### Claim 15 (depends on 1) The distance information acquisition device according to claim 1, further comprising: a distance calculator which generates, using the sequence of received light signals, a distance image indicating a distance to each pixel. ### Claim 16 A multipath detection device for detecting multipath using a light emitter which emits light according to an emission pulse indicating emission and a solid-state imaging element which performs exposure according to an exposure pulse indicating exposure, the multipath detection device comprising: an emission/exposure controller which generates a timing signal indicating a plurality of pairs of the emission pulse and the exposure pulse that have a time difference, the time difference being different in each of the plurality of pairs; and a multipath detector which obtains a sequence of received light signals from the solid-state imaging element by the emission and the exposure that correspond to each of the plurality of pairs, compares the sequence of received light signals that has been obtained and reference data created in advance as a model of a sequence of received light signals in a multipath-free environment, and determines a presence or absence of multipath according to a difference in a comparison result. ### Claim 17 A multipath detection method for detecting multipath using a light emitter which emits light according to an emission pulse indicating emission and a solid-state imaging element which performs exposure according to an exposure pulse indicating exposure, the multipath detection method comprising: generating a timing signal indicating a plurality of pairs of the emission pulse and the exposure pulse that have a time difference, the time difference being different in each of the plurality of pairs; obtaining a sequence of received light signals from the solid-state imaging element by the emission and the exposure that correspond to each of the plurality of pairs; comparing the sequence of received light signals that has been obtained and reference data created in advance as a model of a sequence of received light signals in a multipath-free environment; and determining a presence or absence of multipath according to a difference in a comparison result.