Ground surface estimation method, measurement area display system, and crane

Patent metadata

Field	Value
Publication number	US-2022017336-A1
Application number	US-201917296847-A
Country	US
Kind code	A1
Filing date	Dec 9, 2019
Priority date	Dec 10, 2018
Publication date	Jan 20, 2022
Grant date	—

Abstract

A ground surface estimation method include: performing first estimation in which the continuous region having a largest number of the grids among the continuous regions is estimated as a ground surface; and performing second estimation including: calculating an average altitude value of the representative point of the grids in the non-adjacent continuous region for each of the non-adjacent continuous regions; calculating an average altitude value of the representative point of the grids in the predetermined range of the continuous region estimated as the ground surface; and estimating that a non-adjacent continuous region as the ground surface when a difference between the average altitude value of the representative point of the grids in the non-adjacent continuous region and the average altitude value of the representative point of the grids in a predetermined range of the continuous region estimated as the ground surface is equal to or less than a threshold.

First claim

1 . A ground surface estimation method comprising:
acquiring, by a laser scanner, point cloud data by radiating laser on a measurement region, and calculating an altitude value of a radiation point from the point cloud data; generating, by a data processing section that performs arithmetic processing on the point cloud data, a grid by dividing the measurement region into a plurality of grids, calculating a center-of-gravity position of each of the grids and an average altitude value of the point cloud data in each of the grids, and setting the center-of-gravity position at the average altitude value of the point cloud data in each of the grids as a position of a representative point for each of the grid; recognizing, by the data processing section, a continuous region by recognizing one grid and another adjacent grid of the plurality of grids as the continuous region when a difference in altitude value between the representative point of the one grid and the representative point of the other adjacent grid is equal to or less than an inter-grid threshold, the continuous region being a region where the one grid and the other adjacent grid are continuous; performing, by the data processing section, first ground surface estimation in which the continuous region having a largest number of the grids among the continuous regions is estimated as a ground surface; and performing, by the data processing section, second ground surface estimation including: calculating an average altitude value of the representative point of the grids in the non-adjacent continuous region for each of the non-adjacent continuous regions, the non-adjacent continuous region being the continuous region not adjacent to the continuous region estimated as the ground surface; calculating an average altitude value of the representative point of the grids in the predetermined range of the continuous region estimated as the ground surface; and estimating that a non-adjacent continuous region as the ground surface when a difference between the average altitude value of the representative point of the grids in the non-adjacent continuous region and the average altitude value of the representative point of the grids in a predetermined range of the continuous region estimated as the ground surface is equal to or less than an inter-region threshold.

2 . The ground surface estimation method according to claim 1 , wherein
the predetermined range of the continuous region estimated as the ground surface is a range formed of the grids adjacent to the continuous region between the non-adjacent continuous region and the continuous region estimated as the ground surface.

3 . The ground surface estimation method according to claim 1 , wherein
a width of the grid when the measurement region is divided into the plurality of grids is changed in accordance with a number of the continuous regions in the predetermined range of the non-adjacent continuous region estimated as the ground surface.

4 . The ground surface estimation method according to claim 1 , wherein
in the second ground surface estimation, the non-adjacent continuous region is not estimated as the ground surface when a distance between the non-adjacent continuous region and the continuous region estimated as the ground surface is equal to or larger than a predetermined distance.

5 . A measurement region display system comprising:
a data acquisition section including a laser scanner, the laser scanner acquiring point cloud data by radiating laser on a measurement region; a data processing section that performs arithmetic processing on the acquired point cloud data; and a data display section, wherein: the data processing section
acquires the point cloud data from the data acquisition section, and calculates an altitude value of a radiation point from the point cloud data;
divides the measurement region into a plurality of grids, calculates a center-of-gravity position of each of the grids and an average altitude value of the point cloud data in each of the grids, and sets the center-of-gravity position at the average altitude value of the point cloud data in each of the grids as a position of a representative point for each of the grids;
recognizes one grid and another adjacent grid of the plurality of grids as a continuous region when a difference in altitude value between the representative point of the one grid and the representative point of the other adjacent grid is equal to or less than an inter-grid threshold, the continuous region being a region where the one grid and the other adjacent grid are continuous;
estimates the continuous region having a largest number of the grids among the continuous regions as a ground surface;
estimates a non-adjacent continuous region as the ground surface when a difference between an average altitude value of the representative point of the grids in the non-adjacent continuous region and an average altitude value of the representative point of the grids in a predetermined range of the continuous region estimated as the ground surface is equal to or less than an inter-region threshold, the non-adjacent continuous region being the continuous region not adjacent to the continuous region estimated as the ground surface, the average altitude value of the representative point of the grids in the non-adjacent continuous region being calculated for each of the non-adjacent continuous regions, the average altitude value of the representative point of the grids in the predetermined range of the continuous region estimated as the ground surface being calculated; and
displays the continuous region estimated as the ground surface on the data display section, the continuous region estimated as the ground surface being distinguished from the continuous region other than the continuous region estimated as the ground surface.

6 . A crane comprising:
a swivel base; a boom provided on the swivel base; a laser scanner attached to the boom and acquiring point cloud data; a control apparatus that performs arithmetic processing on the acquired point cloud data; and a display apparatus, wherein: the point cloud data for each position of the laser scanner when radiating laser is acquired by laser radiation while the laser scanner is caused to move in accordance with a swiveling operation of the swivel base, an extending and retracting operation of the boom, and/or a luffing operation of the boom, and the control apparatus
acquires the point cloud data for each position of the laser scanner when radiating the laser, superimposes the point cloud data for each position of the laser scanner when radiating the laser based on each position and attitude of the laser scanner when radiating the laser, and calculates an altitude value of a radiation point;
divides a measurement region of the laser scanner into a plurality of grids, calculates a center-of-gravity position of each of the grids and an average altitude value of the point cloud data in each of the grids, and sets the center-of-gravity position at the average altitude value of the point cloud data in each of the grids as a position of a representative point for each of the grids;
recognizes one grid and another adjacent grid of the plurality of grids as a continuous region when a difference in altitude value between the representative point of the one grid and the representative point of the other adjacent grid is equal to or less than an inter-grid threshold, the continuous region being a region where the one grid and the other adjacent grid are continuous;
estimates the continuous region having a largest number of the grids among the continuous regions as a ground surface;
estimates a non-adjacent continuous region as the ground surface when a difference between an average altitude value of the repre

Assignees

• Tadano Ltd
• The School Corporation Kansai Univ

Inventors

• Ishikawa Iwao
• Kosaka Takayuki
• Kubota Satoshi
• Tanaka Shigenori
• Nakamura Kenji
• Yamamoto Yuhei
• NAKAHARA Masaya

Classifications

• B66C13/22 Primary

  for electric drives (transmitting control pulses B66C13/40; systems or devices of general application H02P) · CPC title

• G06F18/23 Primary

  Clustering techniques · CPC title

• B66C13/46

  Position indicators for suspended loads or for crane elements · CPC title

• G01S17/89 Primary

  for mapping or imaging · CPC title

• G01S7/4808

  Evaluating distance, position or velocity data · CPC title