光学干涉图像处理中基于质量权值的离散余弦变换解包裹相位

为减少噪声对相位恢复过程的影响,快速得到正确的解包裹相位,提出了一种改进的相位解包裹方法——加权离散余弦变换解包裹算法。该方法把离散余弦变换和标识相位数据好坏的质量权值结合起来,兼有速度快和可靠度高的优势。为验证此算法,对模拟和实验得到的包裹相位图添加随机噪声和散粒噪声,同时采用加权与非加权离散余弦变换算法进行处理,所得到的解包裹结果与未加噪声的解包裹相位值进行比较,结果表明,通过加权离散余弦变换算法恢复的相位图比非加权离散余弦变换算法所恢复的相位图更接近于理想值,而且两种算法的运行速度基本相同,这证明提出的算法不仅保证了效率高的优点,而且所恢复的解包裹相位具有较好的噪声免疫能力和可靠度。

Quality Weight Based Discrete Cosine Transform Phase Unwrapping Algorithm in Optical Interferogram Processing

In order to obtain a correct phase unwrapping (PhU) result, as well as to alleviate the effect of noise, a phase unwrapping algorithmweighted discrete cosine transform (DCT) algorithm based on phase derivative variance quality weight is proposed. In testifying the validity of the proposed algorithm, the weighted and non-weighted discrete cosine transform algorithms are used to unwrap the simulated and experimental phase maps with artificial random and shot noise, respectively. The two results derived from the different ways are compared with the same unwrapping phase without artificial noise, respectively. It shows that the phase unwrapped by use of weighted discrete cosine transform method is closer to the ideal results. At the same time, the two algorithms are almost equal in computation time. All these prove that in recovering the true phase, our proposed method not only has high efficiency, but also keeps satisfactory noise robustness and reliability.