{"title":"Image denoising in the presence of non-Gaussian, power-law noise","authors":"Jianbo Gao, Qian Chen, Erik Blasch","doi":"10.1109/NAECON.2012.6531037","DOIUrl":"https://doi.org/10.1109/NAECON.2012.6531037","url":null,"abstract":"In image processing, noise is usually modeled as white Gaussian noise to represent general sensor and environmental clutter, and many effective methods have been developed to remove Gaussian noise. We show here that in many situations, such as Terahertz (ThZ) images or under-water images distorted by wavy surface, noise may be highly non-Gaussian, and even heavy-tailed with power-law distributions. We perceive that such noise may be ubiquitous, such as in images obtained by radar, LIDAR, satellite, and electro-optical visual cameras, in unsteady environments. We show that such noise cannot be effectively reduced by even the best method (block-matching 3D transformation, BM3D) for removing Gaussian noise. A fundamental issue arises of how to develop a proper framework to aptly deal with such non-Gaussian noise. We propose a viable new approach using power-law analysis, and evaluate its effectiveness using well-known images in computer vision community. We show that the new approach, which we call thresholding-median filtering and BM3D (TM-BM3D), works effective on all known types of noise, Gaussian, salt and pepper, and power-law noise.","PeriodicalId":352567,"journal":{"name":"2012 IEEE National Aerospace and Electronics Conference (NAECON)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123483333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Broadband THz filters for THz sensing devices","authors":"V. Sanphuang, N. Nahar, J. Volakis","doi":"10.1109/naecon.2012.6531017","DOIUrl":"https://doi.org/10.1109/naecon.2012.6531017","url":null,"abstract":"We propose a broadband filter using multi-layered frequency selective surfaces (FSS) for terahertz (THz) sensing devices. These types of filter windows are required to be placed in front of THz sensors to increase signal-to-noise ratio and reduce sensor sensitivity to mid IR and visible light. The FSS filter is simulated using polyethylene dielectric layers with fan shaped metal slots. Simulations show excellent flat band-pass response and a sharp out-of-band frequency response in 1–3 THz frequency range, centered at 1.95 THz. The −3 dB bandwidth achieved from this design is 1 THz (1.5THz–2.5THz).","PeriodicalId":352567,"journal":{"name":"2012 IEEE National Aerospace and Electronics Conference (NAECON)","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116366410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}