用灰度值改进双曝光测量物体微小形变的方法

Improvement method of measuring object deformation by using double-exposure with gray-level

数字全息是用数字的方式记录和处理全息图像,通常在使用双曝光法测量物体微小形变时,对于形变量接近入射波长一半的情况一般使用相移的方法,这种方法需要拍摄多幅全息图。为了简化过程,提出将灰度值和双曝光方法相结合测量物体的微小形变。该方法通过画出条纹图的灰度曲线,判断条纹级数,计算出物体形变量;只需拍摄两幅全息图。通过理论分析和实验验证,取得了满意的结果。结果表明,该方法在一定的范围内是可行的。

The usual method for recording and processing hologram images is digital holography, which is also suitable for douhle-exposure to measuring object deformation. However, the deformation near half of the optical wavelength is based on phaseshift method, and it needs more than three hologram images. In order to simplify the method, the double-exposure with gray-level was extended to measure deformation. By using the gray-level, with the image of gray-level distributions, the fringe numbers can be calculated and then the out-of-plane displacement was obtained. This method only needs take two images. Through theoretical analysis and experimentation, the result is satisfactory, which show this method works well in a certain extent.