﻿ 一种基于线结构光的水下目标3维信息测量方法
 机器人 2022, Vol. 44 Issue (5): 564-573 0

XU Pengfei, MENG Hao, LI Tongfei, ZHENG Jinhai, LI Zhigang. A 3D Information Measuring Method of Underwater Targets Based on Line-Structured Light[J]. ROBOT, 2022, 44(5): 564-573.

1. 河海大学，江苏 南京 210024;
2. 中国科学院沈阳自动化研究所机器人学国家重点实验室，辽宁 沈阳 110016

 \begin{align} & \begin{bmatrix} {X_{\rm c}} \\ {Y_{\rm c}} \\ {Z_{\rm c}} \\ 1 \end{bmatrix}= \begin{pmatrix} \mathit{\boldsymbol{R}} & \mathit{\boldsymbol{T}} \\ {\bf{0}} & 1 \\ \end{pmatrix} \begin{bmatrix} {X_{\rm w}} \\ {Y_{\rm w}} \\ {Z_{\rm w}} \\ 1 \end{bmatrix} \end{align} (1)
 \begin{align} & Z_{\rm c} \begin{bmatrix} x \\ y \\ 1 \end{bmatrix} =\begin{bmatrix} f & 0 & 0 & 0 \\ 0 & f & 0 & 0 \\ 0 & 0 & 1 & 0 \end{bmatrix} \begin{bmatrix} {X_{\rm c}} \\ {Y_{\rm c}} \\ {Z_{\rm c}} \\ 1 \end{bmatrix} \end{align} (2)
 \begin{align} & \begin{bmatrix} u \\ v \\ 1 \end{bmatrix} =\begin{bmatrix} \dfrac{1}{{\rm d}x} & 0 & u_{0} \\ 0 & \dfrac{1}{{\rm d}y} & v_{0} \\ 0 & 0 & 1 \end{bmatrix}\begin{bmatrix} x \\ y \\ 1 \end{bmatrix} \end{align} (3)

2.4 摄像机标定

2.5 基于方向向量的线结构光平面快速标定方法

2.5.1 靶标结构设计

 \begin{align} r & =\frac{CA/CB}{DA/DB}=\frac{ca/cb}{da/db} \end{align} (4)
 $$$\begin{split} CA/CB & =C_{y} A_{y} /C_{y} B_{y} =({y_{c} -y_{a}})/({y_{c} -y_{b}}) \\ DA/DB & =D_{y} A_{y} /D_{y} B_{y} =({y_{d} -y_{a}})/({y_{d} -y_{b}}) \end{split}$$$ (5)

 \begin{align} y_{c} =\frac{({y_{b} -y_{a}})({y_{d} -y_{b}})}{r({y_{d} -y_{a}})-({y_{d} -y_{b}})}+y_{b} \end{align} (6)

 \begin{align} a_{1} X_{\rm c} +a_{2} Y_{\rm c} +a_{3} Z_{\rm c} +a_{4} =0 \end{align} (7)

 \begin{align} Z_{\rm c} \begin{bmatrix} u \\ v \\ 1 \end{bmatrix} =\begin{bmatrix} \dfrac{f}{{\rm d}x} & 0 & u_{0} & 0 \\ 0 & \dfrac{f}{{\rm d}y} & v_{0} & 0 \\ 0 & 0 & 1 & 0 \end{bmatrix}\begin{bmatrix} {X_{\rm c}} \\ {Y_{\rm c}} \\ {Z_{\rm c}} \\ 1 \end{bmatrix} \end{align} (8)

 \begin{align} \begin{cases} ({u-u_{0}}){\rm d} x=f_{\rm x} X_{\rm c} /Z_{\rm c} =x \\ ({v-v_{0}}){\rm d} y=f_{\rm y} Y_{\rm c} /Z_{\rm c} =y \end{cases} \end{align} (9)

 图 7 求解标定点原理图 Fig.7 Schematic diagram for solving calibration points

 \begin{align} \begin{cases} \theta_{1} =\arccos \dfrac{\overrightarrow {Oa} \cdot \overrightarrow {Ob}} {| {\overrightarrow {Oa}} |\cdot | {\overrightarrow {Ob}} |} \\[9pt] \theta_{2} =\arccos \dfrac{\overrightarrow {Ob} \cdot \overrightarrow {Oc}} {| {\overrightarrow {Ob}} |\cdot | {\overrightarrow {Oc}} |} \\[9pt] \theta_{3} =\arccos \dfrac{\overrightarrow {Oc} \cdot \overrightarrow {Od}} {| {\overrightarrow {Oc}} |\cdot | {\overrightarrow {Od}} |} \end{cases} \end{align} (11)

 \begin{align} \begin{cases} x_{d} =x_{c} +\sqrt{| {\overrightarrow {CD}} |^{2}-d_{3}^{2}} \\ | {\overrightarrow {CD}} |=\dfrac{d_{3}} {\sin \theta_{5}} \end{cases} \end{align} (18)

 \begin{align} a_{1{\rm w}} X_{\rm w} +a_{2{\rm w}} Y_{\rm w} +a_{3{\rm w}} Z_{\rm w} +a_{4{\rm w}} =0 \end{align} (19)

 图 8 实验环境布置 Fig.8 The experimental environment layout
3.2 图像滤波及激光中心线的提取

 图 9 图像滤波与激光中心线提取效果 Fig.9 Results of image filtering and laser central line extraction
3.3 摄像机标定

 图 10 棋盘格模板 Fig.10 Planar checkerboard

3.4 线结构光平面及位移平台标定

 图 11 靶标上的激光条纹图像 Fig.11 Laser stripe image on the target

 图 12 特征点坐标及线结构光平面拟合结果 Fig.12 Coordinates of feature points and the result of the line-structured light plane fitting

 \begin{align} 1.826X_{\rm c} +0.145Y_{\rm c} -0.39Z_{\rm c} +374.7435=0 \end{align} (21)

3.5 目标物3维点云重构及精度分析

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