摘要
木材被盗案件中,需要先找到被盗的可疑树木,然后和留在地面的基部伐桩进行比对,确认可疑树木为被盗树木。为了辅助公安机关判断可疑木材是否为被盗木材,需要精确测量被盗木材的基部伐桩和可疑木材的截面大小等特征。首先对留在地面的基部伐桩进行拍照,并对找到的可疑木材截面进行拍照,然后比对2个截面的相似性,从而判断可疑木材是否属于被盗木材。由于被盗木材一般数量庞大,摄像机拍照存在畸变,拍照的姿态、角度和焦距以及环境光照都对成像有具体影响,因此,提出采用矩形棋盘格和最小二乘透视变换的方法,将所有的棋盘格角点作为控制点,并根据透视变换的直线特征不变性,构建了一种基于Hough变换的控制点排序方法。该方法能够将不同角度、不同姿态拍摄的图像变换到鸟瞰图像,并缩放到原始尺寸,从而进行测量。对于不同角度、不同姿态、不同焦距、不同光照条件下的图像,本研究提出的透视变换方法均可以把特征棋盘格及棋盘格后面的伐桩图像校正到图像的中间位置,得到伐桩的鸟瞰图,精确地复原伐桩的原貌。对校正后的图像采用MATLAB的imtool工具进行测量,测量结果表明,该方法测量误差最大为2.45%,能满足公安机关对可疑木材是否为被盗木材的辅助判断需求。
In the case of wood theft, it is necessary to find the suspected trees that have been stolen firstly, and then compare them with the base stumps left on the ground to confirm that the suspected trees are stolen trees. In order to assist the public security organ in judging whether the suspected log is stolen, it is necessary to accurately measure the characteristics of the base stump of the stolen log and the section size of the suspected log. In this study, a new me-thod is proposed to assist the public security organ in judging whether the section of the suspicious log is consistent with the left stump. In this method, some photos are taken after a checkerboard is fixed on the cutting pile at the base. Then, the same checkerboard is fixed on the suspicious log section found, and photos are taken. Due to the difference of shooting angle, distance, and posture, it is difficult to directly compare the similarity of two images. Therefore, all the intersections of the checkerboard are taken as the control points, the least squares perspective transformations are performed on the two photos. They are transformed to the perspective of the aerial view, and the similarity of the two sections is compared, so as to determine whether the suspicious log belongs to the stolen log. Therefore, this study proposes a method of rectangular checkerboard and least squares perspective transformation, discusses all corners of the checkerboard as control points, and recommends a control point sorting method based on the Hough transformation according to the in-variance of the line features of perspective transformation. This method can transform the images taken from different angles and different postures into the aerial view and reduce them to the original size for the measurement. For images under different angles, different postures, different focal lengths and different lighting conditions, the perspective transformation method proposed in this study can correct the stump image to the middle of the image, obtain the aerial view o
作者
崔世林
田斐
CUI Shilin;TIAN Fei(Intelligent Manufacturing College,Nanyang Institute of Science and Technology,Nanyang 473004,China)
出处
《林业工程学报》
CSCD
北大核心
2023年第2期151-158,共8页
Journal of Forestry Engineering
基金
河南省重点科技攻关项目(172102210414)。
关键词
矩形棋盘格
最小二乘透视变换
HOUGH变换
控制点排序
原木测量
伐桩图像
rectangular checkerboard
least square perspective transformation
Hough transform
sorting of control points
stump measurement
cutting pile image
