• Title/Summary/Keyword: Noise Removal

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Digital Filter based on Expended Convolution Mask to Reconstruct Impulse Noise Image (임펄스 잡음 영상을 복원하기 위한 확장된 컨벌루션 마스크 기반의 디지털 필터)

  • Cheon, Bong-Won;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2022.05a
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    • pp.431-433
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    • 2022
  • With the development of IoT technology, various technologies such as artificial intelligence and automation are being grafted into industrial sites, and accordingly, the importance of data processing is increasing. Image denoising is one of the basic processes of image processing, and is used as a preprocessing step in many applications. Various studies have been conducted to remove noise, but various problems arise in the process of noise removal, such as image detail preservation, texture restoration, and special noise removal. In this paper, we propose a digital filter using an extended convolutional mask to preserve image detail during the impulse denoising process. The proposed algorithm uses an extended convolution mask as a filtering mask, and obtains the final output by switching the extension level according to the noise level. Simulation was conducted to evaluate the performance of the proposed algorithm, and the performance was analyzed compared to the existing method.

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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 Multiple Filters using Noise Density in Salt and Pepper Noise Environments (Salt and Pepper 잡음 환경에서 잡음 밀도를 이용한 다중 필터에 관한 연구)

  • Kwon, Se-Ik;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2016.05a
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    • pp.666-668
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    • 2016
  • Salt and pepper noise generally occurs due to errors in the transmission channel or sensors and it lowers the resolution of the image and causes visual errors. To remove this salt and pepper noise, SMF(standard median filter), which represents simple algorithm and excellent noise removal performance, is widely used. However preservation characteristics in the pitch areas of the image is rather lacking. Therefore to effectively restore images damaged by salt and pepper noise, the study suggested a multiple filter that applies filters differently according to size by applying noise density threshold value of local mask on noise signal, while preserving non-noise signal.

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Design of real time FIR filter for removal of noise in ECG (ECG 신호의 잡음 제거를 위한 실시간 FIR 필터의 설계)

  • 황선철;이경중;이명호
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.690-693
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    • 1987
  • Base-line wandering and 60Hz noise in ECG are removed by linear phase FIR filter. The important problem in FIR filtering is to reduce the number of impulse response coefficients. It can be reduced by symmetrical impulse response. The ripple is improved by window function .omega.(n). And the determination of filter accuracy is proposed by PRD(percent rms difference) algorithm.

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Noise removal in still images based on modified diffusion equation (개선된 확산방정식에 의한 정지영상의 CCD 잡음 제거)

  • 이석호;강문기;박규태
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 1997.11a
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    • pp.87-90
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    • 1997
  • 본 논문에서는 영상의 잡음(noise) 제거를 위한 새로운 diffusion모델을 제안한다. MOD모델 (mean curvature diffusion model)은 영상의 잡음 제거 때 유발되는 경계선의 blurring을 지양할 수 있는 장점이 있는 반면에 수렴상태(convergence state)를 갖지 못한 단점을 안고 있다. 본 논문에서는 MCD 모델에 min/max switch를 결합시킴으로써 MCD모델이 갖고 있던 문제점을 개선하였다. 제안하는 diffusion 모델은 scheme의 반복적인 적용에 대해서 실질적으로 그 결과가 더 이상 변동하지 않는 수렴상태(convergence state)를 가진 매우 안정적인 시스템이다.

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A Study on the Enhanced Filtering for the Removal of BEMF in BLDC Motors

  • Moon, Yu-Sung;Choi, Jae-Hyun;Kim, Jung-Won
    • Journal of IKEEE
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    • v.23 no.1
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    • pp.310-313
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    • 2019
  • This paper used the majority function to digitally filter back-electromotive force as an explanation of the Brushless DC MOTOR control algorithm. The cause and improvement of motor noise, which are operating in close proximity to high frequency sources, did not use conventional low pass filter and comparator elements. Also, they repeatedly output a noise-free BEMF signal for the input value of the majority detection filtering. These filtering steps can help reduce costs and minimize the area of a PCB by requiring relatively little hardware.

Efficient Detection of Small Unmanned Aerial Vehicles in Cluttered Environment (클러터 환경을 고려한 효과적 소형 무인기 탐지에 관한 연구)

  • Choi, Jae-Ho;Kang, Ki-Bong;Sun, Sun-Gu;Lee, Jung-Soo;Cho, Byung-Lae;Kim, Kyung-Tae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.5
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    • pp.389-398
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    • 2019
  • In this paper, we propose a method to detect small unmanned aerial vehicles(UAVs) flying in a real-world environment. Small UAV signals are frequently obscured by clutter signals because UAVs usually fly at low altitudes over urban or mountainous terrain. Therefore, to obtain a desirable detection performance, clutter signals must be considered in addition to noise, and thus, a performance analysis of each clutter removal technique is required. The proposed detection process uses clutter removal and pulse integration methods to suppress clutter and noise signals, and then detects small UAVs by utilizing a constant false alarm rate detector. After applying three clutter removal techniques, we analyzed the performance of each technique in detecting small UAVs. Based on experimental data acquired in a real-world outdoor environment, we found it was possible to derive a clutter removal method suitable for the detection of small UAVs.

Median Filter Applying Segmented Local Mask in Salt and Pepper Noise Environment (Salt and Pepper 잡음 환경에서 세분화된 국부마스크를 적용한 메디안 필터)

  • Hong, Sang-Woo;Kim, Nam-Ho
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.05a
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    • pp.922-924
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    • 2015
  • Recently, the image processing technologies using the public media such as the film, TV, camera and advertisement have been rapidly developed. However, the deterioration occurs with the image in the process of data processing, transmission and storage, and the typical cause of such deterioration is the salt and pepper noise. Typical filters to remove the salt and pepper noise include CWMF(center weighted median filter) and AMF(adaptive median filter) but such filters bring more or less insufficient characteristics of noise removal and visual error as the noise density gets higher. Thus, this paper proposed the median filter which applied the local mask segmented to 4 areas in order to remove the salt and pepper noise effectively and used PSNR(peak signal to noise ratio) as a criterion of judgment.

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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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