高温下数字图像相关散斑最优成像探究

为了测量材料在高温甚至超高温下的力学性能,采用数字图像相关方法,并研究其在高温下的最优成像。采取不同的散斑制作方法,同时加入不同颜色的高温漆,在不同的温度节点,外加不同光源及相应的滤波片,采集并观察图像是否具有良好的对比度。普通的单色光源在800℃以后会逐渐失效,无法获取图像,而紫外光在1 200℃时依然可以获取较好的图像,且直接利用试件本身颜色作为底色效果更佳。采用紫外光照明可以实现DIC在高温环境下的测量。同时利用黑色或者蓝色散斑直接喷涂在试件上有着最佳的对比度,要优于常规的散斑制作方法。

Optimal imaging of digital image correlation speckle under high temperature

In order to measure the mechanical properties of materials at high temperatures or even at ultra-high temperatures, digital image correlation methods are used and their optimal imaging at high temperatures is studied. Different speckle production methods are adopted and high temperature paints of different colors are added. At different temperature nodes, different light sources and corresponding filters are added to collect and observe whether the image has a good contrast. The ordinary monochromatic light source will gradually fail after 800℃, and the image cannot be obtained. The ultraviolet light can still obtain a better image at 1 200℃, and the color of the test piece itself is better as the background color. UV light illumination can be used to measure DIC in high temperature environment. At the same time, the use of black or blue speckle directly sprayed on the test piece has the best contrast, which is superior to the conventional speckle making method.