High Density Noise Removal by Cascading Algorithms

An advanced non-linear cascading filter algorithm for the removal of high density salt and pepper noise from the digital images is proposed. The proposed method consists of two stages. The first stage Decision base Median Filter (DMF) acts as the preliminary noise removal algorithm. The second stage is either Modified Decision Base Partial Trimmed Global Mean Filter (MDBPTGMF) or Modified Decision Based Unsymmetric Trimmed Median Filter (MDBUTMF) which is used to remove the remaining noise and enhance the image quality. The DMF algorithm performs well at low noise density but it fails to remove the noise at medium and high level. The MDBPTGMF and MDUTMF have excellent performance at low, medium and high noise density but these reduce the image quality and blur the image at high noise level. So the basic idea behind this paper is to combine the advantages of the filters used in both the stages to remove the Salt and Pepper noise and enhance the image quality at all the noise density level. The proposed method is tested against different gray scale images and it gives better Mean Absolute Error (MAE), Peak Signal to Noise Ratio (PSNR) and Image Enhancement Factor (IEF) than the Adaptive Median Filter (AMF), Decision Base Unsymmetric Trimmed Median Filter (DBUTMF), Modified Decision Base Unsymmetric Trimmed Median Filter (MDBUTMF) and Decision Base Partial Trimmed Global Mean Filter (DBPTGMF).Comment: 6 pages, 6 figure

A late neolithic expansion of Y chromosomal haplogroup O2a1-M95 from east to west

The origin and dispersal of Y-Chromosomal haplogroup O2a1-M95, distributed across the Austro Asiatic speaking belt of East and South Asia, are yet to be fully understood. Various studies have suggested either an East Indian or Southeast Asian origin of O2a1-M95. We addressed the issue of antiquity and dispersal of O2a1-M95 by sampling 8748 men from India, Laos, and China and compared them to 3307 samples from other intervening regions taken from the literature. Analyses of haplogroup frequency and Y-STR data on a total 2413 O2a1-M95 chromosomes revealed that the Laos samples possessed the highest frequencies of O2a1-M95 (74% with >0.5) and its ancestral haplogroups (O2*-P31, O*-M175) as well as a higher proportion of samples with 14STR-median haplotype (17 samples in 14 populations), deep coalescence time (5.7 ± 0.3 Kya) and consorted O2a1-M95 expansion evidenced from STR evolution. All these suggested Laos to carry a deep antiquity of O2a1-M95 among the study regions. A serial decrease in expansion time from east to west: 5.7 ± 0.3 Kya in Laos, 5.2 ± 0.6 in Northeast India, and 4.3 ± 0.2 in East India, suggested a late Neolithic east to west spread of the lineage O2a1-M95 from Laos