Noise tolerance of a sub-pixel shift method for upsampling diffraction patterns in coherent X-ray diffraction imaging

In coherent X-ray diffraction imaging, speckles on a coherent diffraction pattern must be sampled at intervals sufficiently finer than the Nyquist interval, which imposes an upper limit on the sample size. To overcome the size limitation, a sub-pixel shift method for upsampling coherent diffraction patterns was proposed. This paper reports on the evaluation of the noise tolerance of the upsampling algorithm by a simulation. The quality of the images reconstructed from the upsampled diffraction pattern and pattern recorded by a detector with an equivalent pixel size was comparable when the optimum number of upsampling iterations is adopted.