1. An image denoising method, comprising the steps of: sequentially selecting a pixel in an image as a current pixel, wherein the pixels around the current pixel are defined as neighborhood pixels; dynamically determining a current search block enclosing the current pixel and a strength parameter and determining a comparison block for each of the pixels in the current search block, wherein the comparison block encloses the each pixel; transforming the comparison block for each of the pixels in the current search block to a frequency domain to form a frequency-domain comparison block; determining a current frequency basis for the frequency-domain comparison blocks; obtaining a similarity between each of the neighborhood pixels and the current pixel in the current search block according to the current frequency basis; determining a weighting for each of the neighborhood pixels related to the current pixel according to the strength parameter, the similarity and a distance between each of neighborhood pixels and the current pixel in the current search block; and weighted averaging each of the neighborhood pixels and the current pixel in the current search block according to the weighting to obtain a reconstruction value of the current pixel.