十六步相移技术在弹痕条纹图分析中的应用

Sixteen-step Phase Shifting Technique in Bullet Trail Fringe Image Analysis

在三维弹痕测量系统中,为了获取较高的测量精度,为此本文提出一种采用十六步相移技术的条纹图处理算法。首先分析了物体三维形貌相位分布获取原理,然后对采集到的弹痕图像进行自适应维纳滤波,去除一部分系统噪声,再利用小波变换对原始图像进行3层sym4小波分解去噪,本系统在小波软阈值分析法的基础上,加入了3层的小波系数分解,同时结合十六步相移法进行相位主值的计算。实验结果表明,弹痕条纹图的位相值曲线更加平滑,原始图像条纹图位相高度偏差的最大值为1.631μm,在经过十六步相移技术处理后,位相主值最大偏差值仅为0.8674μm,对本系统的精度提高奠定了基础。

In 3D bullet trail measurement system, in order to obtain high measurement accuracy, a sixteen-step phase-shifting technique fringe image processing algorithms is presented. First, the principle of phase distribution and achievement in 3D morphology is analyzed. And then, adaptive Wiener filter is used to remove partial noise in collected bullet trail images and sym4 wavelet decomposition is used to process the original image by three-layer to remove system noise. The proposed system introduces three-layer decomposition of the wavelet coefficients based on soft threshold to calculate phase combined with sixteen-step phase-shifting technique. The results show that the phase curve of bullet fringe is smoother, the maximum height deviation of original fringe image is 1.631 μm, and the deviation is 0.867 4 μm by sixteen-step phase-shifting, which improves the system accuracy.