基于小波去噪的T-ray图像复原

Image restoration in T-ray imaging based on wavelet de-noising

针对实时THz脉冲(T-ray)成像系统所成图像分辨率低、受1/f相关噪声干扰严重的特点,提出一种新的基于小波去噪的T-fay图像复原算法.对T-ray图像进行离散小坡变换后,先利用广义交叉确认估计出各个分辨率层的噪声阈值,然后对每个分辨率层的高频子带进行迭代去噪,最后对去噪后的T-ray图像采用Jasson-Van-Cittert算法进行复原处理以提高分辨率.实验结果表明,该方法在提高T-ray图像分辨率的同时,能显著地抑制THz成像系统的1/f相关噪声.创新之处在于以广义交叉确认作为T-ray图像中1/f噪声的估计方法,大幅度提高了图像信噪比(～5 dB),避免了噪声带来的复原算法中的不适定问题,达到较好的图像复原效果.

In order to improve the spatial resolution and reduce l/f noise of real-time THz pulses （T- ray） imaging system, a new method based on wavelet de-nosing and Jasson-Van-Cittert （JVC） image restoration algorithm was presented. After making wavelet transform to a T-ray image, generalized cross validation （GCV） was used to estimate the optimal threshold and de-noising was done in the high frequency sub-bands respectively. The JVC image restoration algorithm was applied to the de-noised T-ray image for resolution improving. Experimental results show that this method can suppress l/f noise successfully and improve the resolution of T-ray image significantly.