Abstract: In view of the correction error problem which is caused by some factors such as dithering, the authors presented a new optical tilt correction method based on grating projection. The method was based on the analysis of each pixel of the data array in a sequence of fringe patterns having multiple frequencies, and setup model for pixel coordinates and pixel-slope. Then skew angles of fringes were calculated by trigonometry with the relationship between tilt angle and pixel-slope. At last, tilt correction was realized. The experimental results show that, the algorithm is capable of accurately detecting angle within the range [-90°,90°],accuracy is 99%. Compared with other algorithms such as Hough transform, the proposed algorithm improves precision and accuracy significantly.

Key words: grating projection, tilt correction, Hough transform, least square method, pixel slope

摘要： 针对现有校正算法因抖动等因素存在的校正误差问题，提出了一种基于光栅投影的倾斜校正算法。通过分析连续频率变化的条纹图像序列，构建像素点位置与像素斜率的转换模型；然后利用光栅图像倾斜角度与像素斜率变化关系，使用三角法计算出倾斜角；最后实现倾斜校正。实验结果表明，该算法可有效检测出［-90°,90°］范围内的倾斜角度，准确率为99%。与现有的Hough变换等倾斜校正算法相比，所提算法检测精确度、准确率明显提高。

关键词: 光栅投影, 倾斜校正, Hough变换, 最小二乘法, 像素斜率