Li Zuoyong, Tang Kezong, Hu Jinmei, Lin Yaming. Directional weighted mean filter for image with salt & pepper noise[J]. Journal of Image and Graphics, 2013, 18(11): 1407-1415. DOI: 10.11834/jig.20131103.
Salt & pepper noise is one of the key factors causing image contamination. Its removal is a research hotspot in image denoising. Directional weighted median filters face some issues when seeking restored gray levels of noise pixels
such as non-exclusion of noise neighbors' disturbance
inaccurate estimation for direction and incomplete depiction of local gray level characteristic. To alleviate the issues
a directional weighted mean filter is proposed. The proposed algorithm first detects noise pixels by using directional gray level differences and extreme judgment
then adaptively takes the weighted gray level mean of recursive or non-recursive filtering window as restored gray levels of noise pixels according to noise density estimation of local window. Simulation results show that
as compared with two existing directional weighted median filters
PSNR values of the proposed algorithm is usually increased by 23 dB and 56 dB
with a more obvious increment for high noise density. In addition
running speed is increased nearly 10 and 30 times.