现有金属激光沉积成形工件是根据几何模型按照设定扫描路径层层叠加而成, 工件易发生变形开裂问题, 其根本原因在于工件局部温度梯度过大和局部应力集中, 对成形过程温度进行实时检测并实现动态扫描路径规划是解决该问题的主要途径, 本文提出了激光沉积成形层面红外图像的温度分区轮廓提取方法。首先采用红外热像仪构建沉积层面温度实时采集系统, 提出了基于像素范围与测量距离匹配的层面红外图像几何坐标快速计算和转换方法;然后采用阈值法对层面温度数据进行分区划分, 并采用基于边缘检测法提取温度分区轮廓;进而解析了分区轮廓出现断环的根本原因在于噪音点存在, 提出了基于断环起终点距离判断的温度分区轮廓闭合连接方法, 为分区动态路径规划和分区扫描顺序优化提供依据。

In the current Laser Deposition Shaping (LDS), a work piece was formed according to the planned scan path from its digital CAD model which is base on layer upon layer accumulated principle, both the local great temperature gradient and the stress concentration in the work piece are the essential reasons of deformation and cracking. The dynamic scan path planning which is base on the real-time sensing of the LDS layer temperature is the major way to solve these problems, a kind of temperature subarea contour extraction method of LDS layer infrared picture is presented. A temperature acquisition system of the forming layer is built by infrared thermal imager, it presents a rapid geometric transformation and coordinate conversion method for layer infrared picture according to the match of temperature subarea pixels and measure distance, temperature subareas are divided from layer temperature dates base of the threshold method, extract the temperature subarea contour through edge connection and contour tracing method, The essential reason of break point contour is the existence of the noise pixel, a connect method for break point contour is presented base on judging the distance between the initial and end points of break point contour. It will provide evidences for dynamic path planning and subarea scanning sequence optimizing.