数字全息显微测量中相位畸变的矫正方法

针对微尺寸(1 mm)透射型物体的数字全息显微测量中存在的相位畸变问题,提出一种相位矫正方法,通过改进预放大离轴菲涅耳数字全息记录光路以及全息图的卷积再现算法,消除了相位分布的一次畸变和二次畸变.使用该方法测量USAF1951分辨率板,成功矫正了其再现像的相位畸变,并得到了横向尺寸0.25 mm区域的清晰相位分布三维重建图.该方法的优点在于通过对记录光路和再现算法的改进,矫正相位畸变,直接得到正确的再现像相位,简化了相位补偿计算的步骤,很大程度地降低了相位重建过程的复杂程度,有利于对物体进行实时探测和快速重建.

Correction method of phase distortion in digital holographic microscopy detection

In order to solve the problem of phase distortion in the micro size (1 mm) transmitting objects measurement based on digital holographic microscopy, a new correction method was proposed. By improving the pre-amplification off-axis Fresnel digital holographic recording system and convolution reconstruction algorithm, the phase distortion including both one-fold and two-fold had been corrected. In the experiment, the phase distortion of USAF1951 resolution board was corrected, and the 3D image of phase distribution of part of the board with size of 0.25 mm was clearly reconstructed. The advantage of this method is eliminating the phase distortion by improved both the hologram recording system and the reconstruction algorithm, which greatly reduced the complicate degree of phase reconstruction process because of cutting the step of phase compensation, and contributes to the on-line detection and fast reconstruction of objects.