Statistical Ratio Rank Ordered Differences Filter for SeaWiFS Impulse Noise Removal

Abstract

Due to the 10-bit design of SEAWIFS instrument and the signal transmission, many SEAWIFS satellite images are expected to have lower digitization noise and corrupted impulse noise. In this paper, we first analyze the characteristics of impulse noise and propose a new rank-ordered filter based on the difference of sequence for mean/standard, which is named as Statistical Ratio Rank Ordered Differences (SRROD) filter. Second, we describe the impulse noise detection and removal algorithm in detail. Compared with the median filter and other existing filters, the SRROD filter could effectively remove impulse noises while preserving other valid pixels without, or only with minor, modification. Through adjusting the lower and upper threshold values, different filter performance could be achieved. We also discuss the blind parameters optimization for non-recursive implementation. Based on the assessment of the distribution map of performance estimator � according to different lower and upper threshold pairs, a nearly optimal threshold could be obtained. Finally, some concluding remarks are also presented in this paper.