NAME: bpass PURPOSE: Implements a real-space bandpass filter which suppress pixel noise and long-wavelength image variations while retaining information of a characteristic size. CATEGORY: Image Processing CALLING SEQUENCE

cntrd: calculates the centroid of bright spots to sub-pixel accuracy. Inspired by Grier & Crocker s feature for IDL, but greatly simplified and optimized for matlab INPUTS: im: image to process, particle should be bright spots on dark

通过对随机信号的处理，将其转换为带限信号，再将其通过不同阶数的带通滤波器，得到滤波后的信号。(By processing the random signal, it can be transformed to band limited signal, and then pass the bandpass filter with different orders to get the filtered signal.)