1. A noise suppression method for a digital image, utilizing an adjacent area of a target pixel in the digital image to conduct a denoising process on the target pixel, the noise suppression method comprising: performing a feature-weighted processing procedure to convert each original pixel in the digital image into a feature-weighted pixel, so as to output a feature-weighted image; according to a position of the target pixel in the digital image, selecting a feature-weighted pixel from a corresponding position in the feature-weighted image as a reference pixel, wherein the target pixel is an arbitrary pixel among all the original pixels of the digital image; performing a similarity computing procedure to generate similarities of the reference pixel relative to the feature-weighted pixels other than the reference pixel; according to the similarities of the reference pixel relative to the other feature-weighted pixels, selecting a feature-weighted pixel for compensation from the other feature-weighted pixels; and performing a pixel compensating procedure to compensate an image feature of the target pixel based on the corresponding similarity according to the original pixel where the feature-weighted pixel for compensation is located.