Analysis of Image Denoising using Wavelet Coefficient and Adaptive Subband Thresholding Technique
Image denoising is a common procedure in digital image processing aiming at the removal of noise which may corrupt an image during its acquisition or transmission while sustaining its quality. A statistical model is proposed depending on the magnitude of wavelet coefficients and noise variance for each coefficient is estimated based on the subband it belongs to using Maximum Likelihood (ML) estimator or a Maximum a Posterior (MAP) estimator. An adaptive thresholding is proposed which is applied to each subband coefficient except the low pass or approximation subband. This is done by fixing the optimum thresholding value depending on the decomposition level. The proposed method describes a new method for suppression of noise in image by fusing the wavelet denoising technique with optimized thresholding function to which a multiplying factor (#945;) is included to make the threshold value dependent on decomposition level. Due to this, the proposed technique yields significantly superior image quality by preserving the edges, producing a better PSNR value. The efficiency is proved on comparing with Bayes shrink (BS), Modified Bayes Shrink (MBS) and Normal Shrink (NS) for different noise level.
Keywords: Image denoising, decomposition level, wavelet coefficients, optimum thresholding
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ABOUT THE AUTHORS
S.Kalavathy
Mrs.S.Kalavathy is the Professor in Mathematics of the Science and Humanities Department in R.M.D.Engineering College. She Passed B.Sc. Mathematics from Madras University in 1983. She passed M.Sc. in Applied Mathematics from Anna University Guindy in the year 1985. Also she had received her M.Phil, degree in Mathematics from Bharathidasan University in the year 1986. At present she is persuing her Ph.D. degree from Dr. M.G.R Educational and Research Institute- University, Maduravoyal, Chennai in the field of Image processing. She is in teaching profession for the past 24 years. She handled almost all engineering mathematics subjects for various discipline in UG and PG courses MBA/MCA. She is a life member of ISTE. She published 2 papers in International Journals and presented papers in refereed national & International Conferences. She is an author of 4 books namely Operations Research with C language, Numerical Methods, Laplace transform and Differential equations, Engineering Mathematics – I.
R.M.Suresh
Dr.R.M.Suresh Passed B.E., CSE from Bharathidasan University in 1989. He passed M.Tech in Computer Engineering from Mysore University in 1992 and completed PhD in Computer science and Engineering in the year 2001. He is in teaching profession for the past 19 years. He has served as a lecturer in CSE Department of Manonmaniam Sundaranar University for a decade and serving RMK group of institution for the past seven years He is also currently serving as Associate Dean (R & D) and Vice Principal of this College. He published 10 papers in International journals and presented 85 papers in refereed national & International Conferences. He had written a book in Tamil “C – Programming” supported by Tamil Nadu Govt. Also conducted 5 summer/winter schools, more than 20 conferences / workshops. He is currently guiding 12 PhD scholars and guided more than 24 M.Phil scholars, 26 M.E., Thesis. He is a member of IEEE, CSI, ISTE, INFITT, IASTE etc.
S.Kalavathy
Mrs.S.Kalavathy is the Professor in Mathematics of the Science and Humanities Department in R.M.D.Engineering College. She Passed B.Sc. Mathematics from Madras University in 1983. She passed M.Sc. in Applied Mathematics from Anna University Guindy in the year 1985. Also she had received her M.Phil, degree in Mathematics from Bharathidasan University in the year 1986. At present she is persuing her Ph.D. degree from Dr. M.G.R Educational and Research Institute- University, Maduravoyal, Chennai in the field of Image processing. She is in teaching profession for the past 24 years. She handled almost all engineering mathematics subjects for various discipline in UG and PG courses MBA/MCA. She is a life member of ISTE. She published 2 papers in International Journals and presented papers in refereed national & International Conferences. She is an author of 4 books namely Operations Research with C language, Numerical Methods, Laplace transform and Differential equations, Engineering Mathematics – I.
R.M.Suresh
Dr.R.M.Suresh Passed B.E., CSE from Bharathidasan University in 1989. He passed M.Tech in Computer Engineering from Mysore University in 1992 and completed PhD in Computer science and Engineering in the year 2001. He is in teaching profession for the past 19 years. He has served as a lecturer in CSE Department of Manonmaniam Sundaranar University for a decade and serving RMK group of institution for the past seven years He is also currently serving as Associate Dean (R & D) and Vice Principal of this College. He published 10 papers in International journals and presented 85 papers in refereed national & International Conferences. He had written a book in Tamil “C – Programming” supported by Tamil Nadu Govt. Also conducted 5 summer/winter schools, more than 20 conferences / workshops. He is currently guiding 12 PhD scholars and guided more than 24 M.Phil scholars, 26 M.E., Thesis. He is a member of IEEE, CSI, ISTE, INFITT, IASTE etc.
