直接解调成像的快速算法

直接解调方法(Direct Demodulate Method, DD)中运用的最多的迭代方法是Richardson-Lucy (RL)迭代. RL迭代的公式可以改写成矩阵形式, 其中包含了主要计算量的两次矩阵乘法在点扩展函数满足平移不变性的情况下可以写成卷积的形式, 而卷积可以使用快速傅里叶变换(Fast Fourier Transform, FFT)做快速计算. 详细介绍了上述过程, 并将该方法应用到了硬X射线调制望远镜(Hard X-ray Modulate Telescope,HXMT)的DD成像中, 通过理论的和模拟的计算对比了优化前后DD方法对计算资源的开销.

Accelerated Direct Demodulation Imaging Method

The most popular iteration method used in Direct Demodulation Method(DD)is Richardson- Lucy(RL)Iteration.The formula of RL iteration can be rewritten in matrix form.There are two matrix multiplications which contain the main computation cost.They can be transformed into convolution if the system is shift-invariant.As is well known,convolution can be computed by Fast Fourier Transform much faster than computed directly.This paper introduces the details of the above procedure,which is called accelerated direct demodulation method(ADD),and applies the procedure to image restorations of Hard X-ray Modulation Telescope data.This paper also compares the computation cost between the original DD and ADD.