相位测量偏折术中基于亚像素相移的噪声抑制算法

Noise Reduction Based on Sub-Pixel Phase-Shift Algorithm in Phase Measuring Deflectometry

由于在相位测量偏折术中一般采用数字投影设备或者数字显示设备,相移间隔为若干像素,最小相移量为单个像素,因此对噪声的抑制也是有限的,为此提出一种基于亚像素相移的噪声抑制算法,通过正弦条纹灰度的连续变化来实现亚像素相移,从而增加相移帧数。并采用N-Bucket算法,解决了相移帧数增加后的计算量问题。计算机模拟及实验均表明,该方法可以有效地抑制噪声影响,提高测量精度。为实际应用中合理地选择相移算法提供了理论依据。

Normally, the digital devices such as computer-controlled screen and digital projector are always used in PMD system. Therefore there is a minimum interval of phase shift namely one-pixel phase-shift. The phase shift number is not infinite, and then the noise reduction is not good. In this paper, an algorithm named sub-pixel phase-shift technique is introduced into the PMD system. The results of numerical simulation and experiments have confirmed its ability of reducing the noise efficiently and improving the measurement precision.