Search

CN-121995389-A - Fuzzy ranging reconstruction method and system

CN121995389ACN 121995389 ACN121995389 ACN 121995389ACN-121995389-A

Abstract

The invention provides a fuzzy ranging reconstruction method and a fuzzy ranging reconstruction system, wherein the method comprises the steps of modulating the pulse frequency of seed light emitted by a laser radar by adopting a floating ladder frequency modulation strategy, randomly selecting the time interval emitted between adjacent seed lights in a prefabricated set, enabling the time modulation quantity between the adjacent seed lights to be unequal, enabling the emitted seed lights to carry ranging noise, respectively storing a seed light sequence emitted by pulses and a return light sequence reflected by a target, wherein the seed light sequence is the time difference between the current seed light and the previous seed light, the return light sequence is the time difference between the current return light and the nearest seed light, and automatically judging the emission period of each return light sequence and reconstructing a real distance value through sequence segmentation, period assumption and verification and mask intensity calculation according to the ranging continuity and the frequency modulation ladder characteristics of the return light sequence. According to the method, full-automatic cross-period identification without manual intervention is realized, and the integrity and accuracy of the point cloud data are improved.

Inventors

  • XU WUJIAN
  • WENG GUOKANG

Assignees

  • 武汉智诚智能技术有限公司

Dates

Publication Date
20260508
Application Date
20260106

Claims (10)

  1. 1. The fuzzy ranging reconstruction method is characterized by comprising the following steps of: s1, modulating the pulse frequency of seed light emitted by a laser radar by adopting a floating ladder frequency modulation strategy, wherein the time interval of emission between adjacent seed lights is randomly selected from a prefabricated set, and the time modulation quantity between the adjacent seed lights is unequal; S2, independently storing a seed light sequence emitted by the pulse and a return light sequence reflected by the target, wherein the seed light sequence is the time difference between the current seed light and the previous seed light, and the return light sequence is the time difference between the current return light and the nearest seed light; S3, dividing the return light sequence according to the ranging continuity and the frequency modulation step characteristic, and solving the emission period of the return light sequence; s4, based on the solved return light period, combining the light speed and the time difference, and reconstructing to obtain a ranging value.
  2. 2. The method according to claim 1, wherein in step S1, the frequency modulation amplitude of the floating step frequency modulation is The transmit time of each pulse is retarded or advanced on a periodic basis.
  3. 3. The method of claim 2, further comprising setting a basic frequency modulation step in step S1 And a plurality of frequency modulation steps N, basic frequency modulation step length The frequency modulation amplitude of the floating ladder frequency modulation is determined by the laser radar scanning frequency In prefabricated collection Randomly selected.
  4. 4. A fuzzy ranging reconstruction method as defined in claim 3, wherein the base fm step size The product of the number of the frequency modulation steps N corresponds to the maximum ranging noise value of two adjacent measuring points.
  5. 5. The method of claim 1, wherein in step S2, a seed light sequence emitted by a pulse is stored, only seed light within n sweep periods before return light is stored, and the value of n is equal to the maximum return light span period number supported by the laser radar.
  6. 6. The method according to claim 1, wherein in step S3, the segmentation of the return light sequences is based on dividing the return light sequences into the same data segment when the difference between the ranging values of two adjacent valid return light sequences is smaller than a first threshold and the number of interruption cycles of the two valid return light sequences is smaller than a second threshold, otherwise, the segmentation is performed.
  7. 7. The method of claim 6, wherein the first threshold value is slightly larger than the maximum ranging noise value, and the second threshold value is set according to the scanning frequency and the scanning rotation speed parameters of the laser radar.
  8. 8. The method according to claim 1, wherein in step S3, the step of solving the emission period to which the return light sequence belongs comprises the steps of: constructing a plurality of ranging sequences under the assumption of the return period, detecting whether the absolute value of ranging change of at least 5 continuous points in the ranging sequences is smaller than a continuity judging threshold value, setting the continuity judging threshold value according to laser radar parameters and scanning scenes, if so, proving that the assumption of the return period is correct, otherwise proving that the assumption is incorrect, taking the correct return period as the initial period of the ranging sequences where the points are located, and expanding and confirming the period attribution of the rest points point by point backwards based on the initial period.
  9. 9. The method for reconstructing a range-finding according to claim 8, wherein, for return points which are not judged by continuity, a mask having a length of not less than 5 is set, the sum of squares of the range differences between adjacent points in different return periods is calculated as the difference intensity, and the difference intensity which is the smallest and is lower than a set threshold is selected Setting a threshold value as a final determination result Is equal to the basic frequency modulation step length 。
  10. 10. A system of a fuzzy ranging reconstruction method as claimed in any one of claims 1 to 9, comprising The seed light modulation module is used for controlling the laser radar to emit pulses according to a floating ladder frequency modulation strategy; The data storage module is used for recording a seed light sequence and a return light sequence; The data processing module is used for executing return light sequence segmentation, period judgment and ranging reconstruction; And the data output module is used for outputting the point cloud data containing the real distance information.

Description

Fuzzy ranging reconstruction method and system Technical Field The invention relates to the technical field of pulse laser ranging, in particular to a fuzzy ranging reconstruction method and a fuzzy ranging reconstruction system. Background The basic principle of the pulse laser radar is that a laser pulse signal is transmitted once and a pulse signal reflected by a target is received, and the distance between a transmitting end and the target is determined by measuring the time difference between the transmitted pulse and the received pulse and combining the speed of light. The laser pulse emitted by the laser radar is called seed light, the laser pulse reflected by the target is called return light, and the longer the distance between the measured target and the seed light, the longer the time interval between the seed light and the return light. The time interval between two adjacent seed lights is called a seed light emission period, which is equal to the reciprocal of the seed light emission frequency, and with the increase of the ranging and the increase of the seed light emission frequency, the situation that new seed lights are emitted before the return lights corresponding to the seed lights reach the laser radar inevitably occurs, so that the true ranging value cannot be judged, and the situation of fuzzy ranging occurs, namely 1 or more seed light pulses exist between the return light pulses and the seed lights corresponding to the return light pulses. The traditional method for solving the fuzzy ranging problem of the laser radar mainly comprises the steps of 1, distributing return light periods in a determined range by limiting a ranging range, enabling the method to have higher limit on a use scene, enabling data processing to manually specify the return light periods, 2, determining the return light periods of subsequent measurement results by giving the return light periods of different angle ranges through first line scanning data and then judging the return light periods based on the continuity of point cloud data, enabling the method to be manually participated and limited in applicable scene, and 3, enabling the return light to have period marks by encoding seed light, wherein the method is high in automation degree, can adapt to various scenes, and is easy to cause lost points and misjudgment in a cross-period area. Aiming at the technical problems, the invention provides a fuzzy ranging reconstruction method and a fuzzy ranging reconstruction system, which comprise a seed light frequency conversion method, a data recording method and a ranging reconstruction method, and solve the problem of fuzzy ranging caused by the phenomenon of laser radar return light cross period. Disclosure of Invention The invention mainly aims to provide a fuzzy ranging reconstruction method and a fuzzy ranging reconstruction system, which solve the problems of lost point misjudgment and manual participation in the inter-period ranging along with the increase of ranging and the increase of seed light emission frequency. In order to solve the technical problems, the invention adopts the following technical scheme: A fuzzy ranging reconstruction method comprises the following steps: s1, modulating the pulse frequency of seed light emitted by a laser radar by adopting a floating ladder frequency modulation strategy, wherein the time interval of emission between adjacent seed lights is randomly selected from a prefabricated set, and the time modulation quantity between the adjacent seed lights is unequal; S2, independently storing a seed light sequence emitted by the pulse and a return light sequence reflected by the target, wherein the seed light sequence is the time difference between the current seed light and the previous seed light, and the return light sequence is the time difference between the current return light and the nearest seed light; S3, dividing the return light sequence according to the ranging continuity and the frequency modulation step characteristic, and solving the emission period of the return light sequence; s4, based on the solved return light period, combining the light speed and the time difference, and reconstructing to obtain a ranging value. Further, in step S1, the floating step frequency modulation has a frequency modulation amplitude ofThe transmit time of each pulse is retarded or advanced on a periodic basis. Further, in step S1, the method further includes setting a basic frequency modulation stepAnd a plurality of frequency modulation steps N, basic frequency modulation step lengthThe frequency modulation amplitude of the floating ladder frequency modulation is determined by the laser radar scanning frequencyIn prefabricated collectionRandomly selected. Base frequency modulation step lengthAnd a plurality of frequency modulation steps N are used for controlling the time modulation range between the adjacent measuring points so as to inhibit the distance blurring. Further, the