应用隧道探索算法提取莫尔条纹偏移量

Extracting MoiréFringe Deviation with Tunnel-exploring Algorithm

为了精确提取莫尔条纹偏移量,提出了隧道探索算法,并将其应用于实际莫尔条纹分析.使用双光栅产生莫尔条纹,抓拍多方向投影.应用数字图像处理技术,追踪分析实验莫尔条纹.首先,追踪各条纹的极大值分布,根据条纹极大值分布挖掘条纹隧道,调整挖掘宽度,即像素宽度,既实现隧道贯通,又不干预相邻条纹.然后,二值化莫尔图,噪声滤波,滤除条纹隧道壁上的噪声毛刺,使隧道壁趋于光滑.最后,根据两侧隧道壁的布局,探索条纹隧道走向,提取隧道走向数据,获得条纹偏移量.并进一步转换为偏折角,即光学计算机层析投影.应用非线性自适应迭代重建算法对偏折角进行迭代重建.结果发现,最高重建截面温度是492℃,额定电热器表面温度大约500℃,重建截面恰恰在电热器上表面上方,所以重建结果是有效的.

In order to accurately extract out Moirfi fringe deviations, the tunnel-exploring algorithm was proposed,and used to analyze Moire patterns. The Moir~ patterns were produced with double Ronchi gratings,and captured in many projecting directions. With the technology processing digital images, the experiment Moire patterns were tracked and further analyzed with a series of analyzing techniques. This series of processing algorithms are called tunnel-exploring algorithm here. The tunnel-exploring algorithm includes tracking maximums of fringes, excavating fringe tunnels, binarizing Moire patterns, filtering out noise,exploring fringe tunnels, extracting the track of tunnel extension, and so on. First, each of Moire fringes is tracked based on its column pixels＇ maximums. According to the maximums＇ distributions, the fringes are excavated into tunnels. Each trenched width, viz. the width of pixels, is adjusted to make the tunnel link up,hut not to interfere the adjacent fringes. Second, the Moire patterns with excavated tunnels are binarized and filtered. The fringe tunnels are smoothed out by filtering out the noise on both sides of each tunnel. Last,the fringe tunnels are explored based on the distributions of both sides of each tunnel, and the track of each tunnel extension are extracted out, then the fringest deviations are obtained. Therefore, by tunnel-exploring algorithm processing, the fringes＇ deviations were obtained. Then, they are used to reconstruct a section temperature distribution of the flow field using nonlinear auto-adjusting iterative reconstruction technique. As the result, the highest temperature reconstructed is 492℃. The rated surface temperature of the heater is about 500℃. The reconstructed section is just above the heater, so the reconstruction is considered reasonable.