中文说明： 结合PCA的尺度不变特征变换(SIFT)算法，计算十字叉丝的在不同距离的衍射图像,采用了小波去噪的思想，信号处理中的旋转不变子空间法，实现串口的数据采集，LDPC码的完整的编译码。
English Description：
Combined with the SIFT algorithm of PCA, the diffractive images of cross wires at different distances are calculated. The idea of wavelet de-noising and rotation invariant subspace method in signal processing are adopted to realize the data acquisition of serial port and complete encoding and decoding of LDPC code.