X射线编码三维成像重叠噪声的抑制

Reduplicate noise reduction of 3 D X ray coded imaging

Ｘ 射线编码三维成像系统中，减少观察层上的重叠噪声是提高图像信噪比的有效方法。该文描述了一种新的解码方法，该方法通过对编码图像在频域进行梳状滤波并在空间重建，可以获得较低重叠噪声的观察层图像。理论分析表明： 所获得的观察层图像的重叠噪声残余能量小于１／ｍ （ｍ为编码图像的数量）。实验中对采用相关解码法和频域梳状滤波法所获得的层析图像进行了比较。结果表明： 采用频域梳状滤波法所获得图像的信噪比要高于采用相关解码法所获得图像的信噪比，与理论分析相符。

In a three dimensional X ray coded imaging system, it is effective method to reduce the reduplicate noise of a certain layer image for enhancing the signal noise rate. This paper describes a new decode method which reduces the reduplicate noise of coded images and reconstructs tomography with a comb shaped filter in frequency spectrum. Using this mehtod, a certain layer image that has less reduplicate noise can be obtained. Theoretical analysis apperars that energy of reduplicate noise is reduced to less than 1/ m (m is the number of coded images) in the certain layer image. Comparing the correlation decode method with this new method for a certain layer image obtained in experiments, it is proved that the signal noise rate of image obtained with latter method is higher than one with former method in accordance with theroretical analysis.