• Title/Summary/Keyword: median filters

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Comparison of Filter Selection for Compressed Sensing (압축센싱을 위한 필터선택 비교)

  • Pham, Phuong Minh;Shim, Hiuk Jae;Jeon, Byeungwoo
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2012.11a
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    • pp.188-190
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    • 2012
  • Compressed Sensing (CS) has been developed for several years. Among many CS algorithms for image, the Block-based Compressed Sensing with Smoothed Projected Landweber (BCS-SPL) demonstrates its excellent performance in low-complexity and near-optimal reconstruction. Several noise filtering algorithms of image reconstruction have been introduced such as the Wiener or the median filters, etc. In general, each filter has its own advantages and disadvantages depending on specific coding scheme. In this paper, we show that reconstruction performance can be varied according to the choice of filter. When a sub-rate value is changed, different filter causes different effect as well. Concerning the sub-rate, an inner filter can be chosen to improve the reconstructed image quality.

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Image Processing for Mixed Noise Removal (복합 잡음 제거를 위한 영상처리)

  • Lee, Kyung-Hyo;Kim, Nam-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.12
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    • pp.2701-2706
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    • 2009
  • There are Impulse noise and AWGN in a general image processing. Various methods have been proposed to remove these noises. Well-known filters are Mean, Min-max and Median filter and these show different characteristics depending on the noises. When Impulse noise and AWGN are in superposition environment, single filter doesn't remove noises well. Therefore in this paper, we suggested a switching filter using a probability of noise to restore images in this environment. And we compared a filter with conventional method through simulations.

A Study on Enhancing Ship`s Radar Detecting Efficiency by Wavelet and Morphology Median Filter (Wavelet과 Morphology Median 필터를 이용한 선박용 Radar 탐지 효율 향상을 위한 연구)

  • Jeong, Gi-Ryong
    • Journal of Navigation and Port Research
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    • v.26 no.1
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    • pp.28-34
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    • 2002
  • Irregular reflected signals on a sea surface make clutters to a ship's radar image. Clutters are similar to Gaussian white noises which are very harmful for detecting objecting at sea by a ship's radar. To remove the clutter effects, many papers show the algorithms by antenna, filters, and so on. This paper shows a new algorithm which uwes Wavelet and Morphology median filter conceps for removing clutter and enhancing image in order to detect well a distressed of being rescued ship in a rough weather condition at sea.

Adaptive Switching Median Filter for Impulse Noise Removal Based on Support Vector Machines

  • Lee, Dae-Geun;Park, Min-Jae;Kim, Jeong-Ok;Kim, Do-Yoon;Kim, Dong-Wook;Lim, Dong-Hoon
    • Communications for Statistical Applications and Methods
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    • v.18 no.6
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    • pp.871-886
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    • 2011
  • This paper proposes a powerful SVM-ASM filter, the adaptive switching median(ASM) filter based on support vector machines(SVMs), to effectively reduce impulse noise in corrupted images while preserving image details and features. The proposed SVM-ASM filter is composed of two stages: SVM impulse detection and ASM filtering. SVM impulse detection determines whether the pixels are corrupted by noise or not according to an optimal discrimination function. ASM filtering implements the image filtering with a variable window size to effectively remove the noisy pixels determined by the SVM impulse detection. Experimental results show that the SVM-ASM filter performs significantly better than many other existing filters for denoising impulse noise even in highly corrupted images with regard to noise suppression and detail preservation. The SVM-ASM filter is also extremely robust with respect to various test images and various percentages of image noise.

A Study on the Modified Adaptive Median Filter for Removing Salt and Pepper Noise (Salt and Pepper 잡음 제거를 위한 변형된 적응 메디안 필터에 관한 연구)

  • Hong, Sang-Woo;Hwang, Yeong-Yeun;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.903-905
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    • 2015
  • The need for digital devices is increasing in the digital age. In general, noise in images occurs during the process of compression, recognition and processing due to many reasons. Some of the filters used to remove salt and pepper noise include SMF, CWMF and AMF. In areas where the noise density is high, the removal of noise is undermined. This paper suggests an adjusted median filter algorithm that preserves the non-noise pixels while transforming the noise pixels to more effectively remove salt and pepper noise.

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A Study on Repeated Processing using the Modified Median Filter in a High-Density Salt and Pepper Noise Environments (고밀도 Salt and Pepper 잡음 환경에서 반복처리를 이용한 변형된 메디안 필터에 관한 연구)

  • Hong, Sang-Woo;Gwon, Se-Ik;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.312-314
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    • 2015
  • With progress in information technology, demand for imaging devices such as display devices is increasing. But noise occurs due to various reasons during the process of acquiring, transmitting or processing the image data. Filters used to remove salt and pepper noise include SMF, CWMF and AWMF. In areas where the noise density is high, the removal of noise is undermined. This paper suggests an adjusted median filter algorithm that transforms the noise pixels to more effectively remove salt and pepper noise.

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A Study on Modified Median Filter Algorithm for Degraded Image of Impulse Noise (임펄스 잡음에 훼손된 영상을 위한 변형된 메디안 필터 알고리즘에 관한 연구)

  • Hong, Sang-Woo;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2014.05a
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    • pp.798-800
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    • 2014
  • In recent years, according to the improvement of Digital image technology have been recently developed most of communication technology from multimedia communication service as well as image data transmission. But In the process of storing and transmitting noise is still generated in noise and the image degrades rapidly quality of a lot of image impulse noise. To eliminate this noise, SMF, CWMF, SWMF etc. The filters have been proposed to interfere with the noise characteristics of the filter are somewhat sufficient. Therefore, in this paper, in order to remove impulse noise is proposed a modified median filter. And impulse noise removal algorithms to confirm the existed PSNR(peak signal to noise ratio) from using conventional methods were compared.

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An Impulse Noise-Robust Wiener Filter

  • Park, Soon-Young
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1992.06a
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    • pp.33-36
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    • 1992
  • In this paper we propose the impulse noise-robust Wiener filter based on a combination of Wiener and modified trimmed mean(MTM) filters. The robust Wiener filter uses the trimming operation of the MTM filter to replace the outliers with the median within the window and the new set of samples which can be considered as the random process with same mean are inputted into the following Wiener filter. We show that the robust Wiener filter is effective in frequency selective filtering of nonstationary signals while preserving signal edges with the rejection of impulse noise.

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Performance Comparison of Some Image Restoration Filter for Various Noises (각종 잡음에 대한 영상복원 필터들의 성능 비교)

  • 김남철;정성환
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.3
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    • pp.493-503
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    • 1987
  • Performances of some image restoration filters are compared and evaluated on SNR gain and subjective test. Test images used here are the GIRL and PLANT images corrupted by Gaussian, uniform, BSC, and impulse noise, respectively. Experimental results show that the scalar DCT-Wiener filter among them is comparatively superior to others in Gaussian and uniform noise. On the other hand, the median filter is much better than others in BSC and impulse noise.

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Swell Noise Attenuation Using a Cascade of F-X Filter and Median Filter (F-X 필터와 중앙값 필터를 연속적으로 사용한 파랑잡음 제거)

  • Kim, Sookwan;Hong, Jong Kuk
    • Geophysics and Geophysical Exploration
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    • v.15 no.4
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    • pp.199-208
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    • 2012
  • High-amplitude swell noises (HASN) are very difficult to eliminate from the marine seismic data. In this paper, we applied F-X filter and median filter in order to suppress HASN. Test data have been acquired on the northern offshore of the South Shetland Islands in December, 2010. Parts of data have been contaminated by HASN caused by bad weather during the cruise. We applied F-X filter and median filter to test data with HASN. After F-X filtering, most of non-coherent noises and small-amplitude swell noises are eliminated effectively but HASN are still remained significantly. With median filter, HASN was suppressed better than F-X filter, however some of non-coherent noises are still remains. We applied a cascade of two filters and results show HASN and non-coherent noises are suppressed effectively. After the cascade of two filtering, it is possible to define reflection layers clearly on the velocity spectrum and to produce better stacked section with a good signal-to-noise ratio.