Evaluation in spatial resolution of denoised image in Fresnel transform imaging technique by zero-filling

Abstract

There is an image reconstruction method applying the Fourier transform after a quadratic phase modulations in the Fresnel transform imaging technique. If the outside of the view data area of Fourier space is filled up with the zero data previous to the reconstruction of images in the Fresnel transform method, the spectrum of noise is diffused into the area by the quadratic phase modulation and the image information becomes distribution that concentrates locally. When the signal is returned to the Fresnel transform signal space before interpolation by a series of opposite direction processing after the noise is eliminated by the threshold filtering etc. in the zero filled space, a reconstructed image with little deteriorated spatial resolution and has an excellent SNR improvement characteristic can be obtained using usual Fresnel transform image reconstruction technique. In the study, the deterioration extent of the spatial resolution of a reconstructed image by the proposed method was examined, and the comparison examination with the processing image by Wiener filtering was done.