The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Tomas Tichý - One of the best experts on this subject based on the ideXlab platform.
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a Smoothing Filter based on fuzzy transform
Fuzzy Sets and Systems, 2011Co-Authors: Michal Holcapek, Tomas TichýAbstract:This paper is devoted to the Smoothing of discrete functions using the fuzzy transform introduced by Perfilieva. We generalize a Smoothing Filter based on the fuzzy transform recently proposed by us to obtain a better control on the smoothed functions. For this purpose, a generalization of the concept of fuzzy partition is suggested and the Smoothing Filter is defined as a combination of the direct discrete fuzzy transform and a slightly modified inverse continuous fuzzy transform. An approximation behavior, total variation of smoothed functions and statistical properties including the description of the white noise reduction and the asymptotic expression of bias and variance are investigated and discussed. The proposed Filter is compared with the Nadaraya-Watson estimator and the results are illustrated assuming financial data.
Rena Lee - One of the best experts on this subject based on the ideXlab platform.
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su e i 62 a new metal artifact reduction algorithm using edge preserving Smoothing Filter
Medical Physics, 2013Co-Authors: Jeongtae Kim, H Nam, Rena LeeAbstract:Purpose: Metallic materials such as tooth supplement or surgical clip lead to metal artifacts on the X‐ray computed tomographic (CT) image. In this study, we have developed a new metal artifact reduction algorithm. To improve the image quality from metal artifacted data, our algorithm uses edge preserving interpolation method with BM3D Smoothing algorithm. For evaluation, we used both real human dental data with metal artifacts and metal implemented phantom. Methods: Real metal artifacted data was obtained at Ewha womans university Mokdong hospital. Metal implemented phantom containing air, water, teflon, metalis made to evaluate the performance of the proposed algorithm. With obtained projection data, metal part is extracted from the back‐projection image. Once the metal location and size is obtained, all corrupted non‐metal part is recovered using edge preserving wavelet interpolation. With interpolated data, reconstruct image with Filtered back‐projection. Apply BM3D to smooth the reconstructed image with edge preserving. BM3D is a state‐of‐art Smoothing algorithm, which uses block information to get the similarity of the image. Replace the metal data from the smoothed image and continue doing this forward‐and backward projection iteratively. Our algorithm is based on the iterative reconstruction algorithm combined with the wavelet based interpolation with edge preserving Smoothing Filter. Results: We compared the proposed algorithm with Filtered back‐projection and iterative reconstruction algorithm with bilinear interpolation and Gaussian Smoothing Filter. For the evaluation, we used visual comparison, and quantitative comparison using student t‐test. For the real data, there is no exact solution. Thus only visual comparison can be applied. For the phantom data, we did the quantitative error comparison as well as visual comparison. The proposed algorithm outperformed results in both real and phantom data. Conclusion: We have developed a new CT reconstruction algorithm for metal artifact reduction and demonstrated its superiority compared with other algorithms.
David K Han - One of the best experts on this subject based on the ideXlab platform.
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single image haze removal with wls based edge preserving Smoothing Filter
International Conference on Acoustics Speech and Signal Processing, 2013Co-Authors: Dubok Park, David K HanAbstract:Images captured under hazy conditions have low contrast and poor color. This is primarily due to air-light which degrades image quality according to the transmission map. The approach to enhance these hazy images we introduce here is based on the `Dark-Channel Prior' method with image refinement by the `Weighted Least Square' based edge-preserving Smoothing. Local contrast is further enhanced by multi-scale tone manipulation. The proposed method improves the contrast, color and detail for the entire image domain effectively. In the experiment, we compare the proposed method with conventional methods to validate performance.
David Watling - One of the best experts on this subject based on the ideXlab platform.
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a general stochastic process for day to day dynamic traffic assignment formulation asymptotic behaviour and stability analysis
Transportation Research Part B-methodological, 2016Co-Authors: Giulio Erberto Cantarella, David WatlingAbstract:This paper presents a general modelling approach to day-to-day dynamic assignment to a congested network through discrete-time stochastic and deterministic process models including an explicit modelling of users’ habit as a part of route choice behaviour, through an exponential Smoothing Filter, and of their memory of network conditions on past days, through a moving average or an exponentially Smoothing Filter. An asymptotic analysis of the mean process is carried out to provide a better insight. Results of such analyses are also used for deriving conditions, about values of the system parameters, assuring that the mean process is dissipative and/or converges to some kind of attractor. Numerical small examples are also provided in order to illustrate the theoretical results obtained.
Jong Beom Ra - One of the best experts on this subject based on the ideXlab platform.
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a deblocking Filter with two separate modes in block based video coding
IEEE Transactions on Circuits and Systems for Video Technology, 1999Co-Authors: Jaeyoun Yi, Jong Beom RaAbstract:This paper presents a method to remove blocking artifacts in low bit-rate block-based video coding. The proposed algorithm has two separate Filtering modes, which are selected by pixel behavior around the block boundary. In each mode, proper one-dimensional Filtering operations are performed across the block boundary along the horizontal and vertical directions, respectively. In the first mode, corresponding to flat regions, a strong Filter is applied inside the block as well as on the block boundary because the flat regions are more sensitive to the human visual system (HVS) and the artifacts propagated from the previous frame due to motion compensation are distributed inside the block. In the second mode, corresponding to other regions, a sophisticated Smoothing Filter which is based on the frequency information around block boundaries, is used to reduce blocking artifacts adaptively without introducing undesired blur. Even though the proposed deblocking Filter is quite simple, it improves both subjective and objective image quality for various image features.