为了实现对热轧钢板的在线厚度测量，建立了自动激光测厚系统。对该系统所采用的机械设计、光路设计、基于MATLAB的图像算法等进行了研究。首先使用激光器将激光倾斜投射到待测钢板的侧面上，并在激光器前方设置一块挡板，挡住水平方向上的部分光线。接着使用工业摄像机将被测板上的激光光斑成像于CCD靶面上。然后根据CCD上挡板所成像的位置计算出钢板的离焦量。最后根据CCD上钢板侧面所成像高和钢板的离焦量与待测板厚的几何关系，计算出钢板的厚度。结果表明,钢板厚度为8mm~120mm时，系统测量精度为0.32mm，低于测量系统要求的±0.5mm；测量系统受高温辐射影响较小。能够满足工业生产线上热轧钢板自动厚度测量的稳定性好、精度高、受外界干扰小等要求。

In order to measure the thickness of the hot-rolled steel plate on line, an automatic laser gauging system was established, and its mechanical design and optical design, image algorithm based on MATLAB were investigated. Firstly,the laser beam was inclined to project onto the side of the plate,and a baffle is setted to block the part of light at horizon.Secondly, the laser spot on the tested plate is imaged to CCD target surface in an industrial video camera.Then the defocusing amount is calulated based on the the CCD images.Finally,according to the geometric relationship between actual thickness of the plate to be measured and the imaging height of the plate flank in the CCD and the defocusingamount, the thickness of the steel plate is calculated. Experimental results indicate that the precision of the system is 0.32mm, smaller than the measurement system requirements ±0.5mm when the plate thickness between 8mm and 120mm. This measuring system has less influence induced by high temperature radiation.It can satisfy the system requirements of stabilization,higher precision and rapidity,as well as little interference.