基于能量的DSPI相位图正余弦降噪

摘要

针对数字散斑干涉(Digital Speckle Pattern Interferometry,DSPI)测量中散斑噪声干扰会导致相位提取困难、测量灵敏度降低的问题,提出基于能量的DSPI相位图正余弦滤波法,克服传统滤波方法不具有自适应性的不足,提高了相位图质量.该方法根据正交小波包能量估算DSPI相位图中的噪声能量;对相位图分别进行正余弦变换,采用均值法平滑处理;利用噪声能量设定滤波阈值,实现相位图有效滤波,文中将噪声能量与正余弦滤波结合可以自适应地进行降噪处理,利用能量控制图像滤波效果.仿真和实验结果表明,基于能量的正余弦滤波法较传统方法可以减少50% 的循环次数.证明了本文提出的方法能够有效地对数字散斑干涉相位图进行滤波,提高信噪比.%The speckle noise in digital speckle pattern interferometry(DSPI)results in difficulty in phase extraction and decreases measurement sensitivity.A denoising method using sine-cosine filte-ring and signal energy was proposed to smooth phase maps of DSPI.It exceeded traditional sine-cosine denoising method in adaptively and phase map quality.In the method,noise energy of DSPI phase map was estimated by energy of orthogonal wavelet packet.The phase map was transformed by sine-cosine method and was smoothed by average filtering.The phase map was finally denoised efficiently after the noise threshold was set by the noise energy.The combination of noise energy and sine-cosine filtering reduced noise adaptively.The image filtering effect was controlled by the noise energy.Emu-lational and experimental results both show that the proposed method can reduce the number of cycles by 50% compared to conventional methods.T he proposed method can also filter the DSPI phase maps effectively and improve the noise ratio.