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Statistical algorithm and application for the noise variance estimation (영상 잡음의 분산 추정에 관한 통계적 알고리즘 및 응용)

  • Kim, Yeong-Hwa;Nam, Ji-Ho
    • Journal of the Korean Data and Information Science Society
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    • v.20 no.5
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    • pp.869-878
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    • 2009
  • Image restoration techniques such as noise reduction and contrast enhancement have been researched for enhancing a contaminated image by the noise. An image degraded by additive random noise can be enhanced by noise reduction. Sigma filtering is one of the most widely used method to reduce the noise. In this paper, we propose a new sigma filter algorithm based on noise variance estimation which effectively enhances the degraded image by noise. Specifically, the Bartlett test is used to measure the degree of noise with respect to the degree of image feature. Simulation results are also given to show the performance of the proposed algorithm.

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Adaptive Noise Reduction Algorithm for Image Based on Block Approach (블럭 방법에 근거한 영상의 적응적 잡음제거 알고리즘)

  • Kim, Yeong-Hwa
    • Communications for Statistical Applications and Methods
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    • v.19 no.2
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    • pp.225-235
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    • 2012
  • Noise reduction is an important issue in the field of image processing because image noise worsens the quality of the input image. The basic difficulty is that the noise and the signal are not easy to distinguish. Simple moothing is one of the most basic and important procedures to remove the noise, however, it does not consider the level of noise. This method effectively reduces the noise but the feature area is simultaneously blurred. This paper considers the block approach to detect noise and image features of the input image so that noise reduction could be adaptively applied. Simulation results show that the proposed algorithm improves the overall quality of the image by removing the noise according to the noise level.

Estimation of the Noise Variance in Image and Noise Reduction (영상에 포함된 잡음의 분산 추정과 잡음제거)

  • Kim, Yeong-Hwa;Nam, Ji-Ho
    • The Korean Journal of Applied Statistics
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    • v.24 no.5
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    • pp.905-914
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    • 2011
  • In the field of image processing, the removal noise contamination from the original image is essential. However, due to various reasons, the occurrence of the noise is practically impossible to prevent completely. Thus, the reduction of the noise contained in images remains important. In this study, we estimate the level of noise variance based on the measurement of the relative strength of the noise, and we propose a noise reduction algorithm that uses a sigma filter. As a result, the proposed statistical noise reduction methodology provides significantly improved results over the usual sigma filtering regardless of the level of the noise variance.

Noise reduction by sigma filter applying orientations of feature in image (영상에 포함된 특징의 방향성을 적용한 시그마 필터의 잡음제거)

  • Kim, Yeong-Hwa;Park, Youngho
    • Journal of the Korean Data and Information Science Society
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    • v.24 no.6
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    • pp.1127-1139
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    • 2013
  • In the realization of obtained image by various visual equipments, the addition of noise to the original image is a common phenomenon and the occurrence of the noise is practically impossible to prevent completely. Thus, the noise detection and reduction is an important foundational purpose. In this study, we detect the orientation about feature of images and estimate the level of noise variance based on the measurement of the relative proportion of the noise. Also, we apply the estimated level of noise to the sigma filter on noise reduction algorithm. And using the orientation about feature of images by weighted value, we propose the effective algorithm to eliminate noise. As a result, the proposed statistical noise reduction methodology provides significantly improved results over the usual sigma filtering and regardless of the estimated level of the noise variance.

Image Noise Reduction Filter Based on Robust Regression Model (로버스트 회귀모형에 근거한 영상 잡음 제거 필터)

  • Kim, Yeong-Hwa;Park, Youngho
    • The Korean Journal of Applied Statistics
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    • v.28 no.5
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    • pp.991-1001
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    • 2015
  • Digital images acquired by digital devices are used in many fields. Applying statistical methods to the processing of images will increase speed and efficiency. Methods to remove noise and image quality have been researched as a basic operation of image processing. This paper proposes a novel reduction method that considers the direction and magnitude of the edge to remove image noise effectively using statistical methods. The proposed method estimates the brightness of pixels relative to pixels in the same direction based on a robust regression model. An estimate of pixel brightness is obtained by weighting the magnitude of the edge that improves the performance of the average filter. As a result of the simulation study, the proposed method retains pixels that are well-characterized and confirms that noise reduction performance is improved over conventional methods.