• 한국전산유체공학회:학술대회논문집
• /
• 2007.10a
• /
• pp.209-213
• /
• 2007

This paper presents the high order conservative interpolation methods. This method has been successfully implemented into a cell-centered finite volume methods code. Results using high order and maintaining conservation interpolation method are more accurate compared to bilinear interpolation.

• 한국전산유체공학회:학술대회논문집
• /
• 2011.05a
• /
• pp.261-265
• /
• 2011

An adaptive wavelet transformation method with high order accuracy is proposed to allow efficient and accurate flow computations. While maintaining the original numerical accuracy of a conventional solver, the scheme offers efficient numerical procedure by using only adapted dataset. The main algorithm includes 3rd order wavelet decomposition and thresholding procedure. After the wavelet transformation, 3rd order of spatial and temporal accurate high order interpolation schemes are executed only at the points of the adapted dataset. For the other points, high order of interpolation method is utilized for residual evaluation. This high order interpolation scheme with high order adaptive wavelet transformation was applied to unsteady Euler flow computations. Through these processes, both computational efficiency and numerical accuracy are validated even in case of high order accurate unsteady flow computations.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.9
• /
• pp.1276-1282
• /
• 2013

This paper presents a demosaicking method based on high-order interpolation with parameters. Demosaicking is an essential process in capturing color images through a single sensor-array. Thus, a lot of methods including the Hamilton-Adams(HA) method has been studied in this literature. However, the image quality depends on various factors such as contrast and correlation in color space; existing algorithms depend on test images in use. Consequently, a new test image set was suggested to develop demosaicking algorithms properly. According to previous studies, the HA method shows high performances with the new test data set. In this paper, we improve the HA method using high-order interpolation with parameters. Also, we provide an analysis and formulations for the proposed method. To evaluate our method, we compare our method with the existing methods both objectively and subjectively. The experimental results indicate that the proposed method is superior to the existing methods.

• Proceedings of the IEEK Conference
• /
• 2000.06d
• /
• pp.171-173
• /
• 2000

In this paper, we present a new interpolation method for the color filter away(CFA). In order to capture color images. typical input devices use a single chip CCD imaging sensor with color filter array. As a result, the single chip CCD does not provide sufficient color resolutions since it arranges different color filters sequentially on a single CCD, resulting in aliasing noise and loss of resolution. In order to reconstruct high quality color images, we propose to use the interpolation algorithm using high order B-splines. Experiments show promising results.

• Proceedings of the IEEK Conference
• /
• 2000.06d
• /
• pp.242-245
• /
• 2000

In this paper, we present a color interpolation technique based on artificial neural networks for a single-chip CCD (charge-coupled device) camera with a Bayer color filter array (CFA). Single-chip digital cameras use a color filter array and an interpolation method in order to regenerate high quality color images from sparsely sampled images. We applied 3-layer feedforward neural networks in order to interpolate missing pixel from surrounding pixels. And we compared the proposed method with conventional interpolation methods such as the proposed interpolation algorithm based on neural networks provides a better performance than the conventional interpolation algorithms.

• Journal of Korea Multimedia Society
• /
• v.17 no.12
• /
• pp.1393-1401
• /
• 2014

This paper presents an adaptive image interpolation method using a pixel-based neighbor embedding which is modified from the patch-based neighbor embedding of contemporary super resolution algorithms. Conventional interpolation methods for high resolution detect at least 16-directional edges in order to remove zig-zaging effects and selectively choose the interpolation strategy according to the direction and value of edge. Thus, they require much computation and high complexity. In order to develop a simple interpolation method preserving edge's directional shape, the proposed algorithm adopts the simplest Haar wavelet and suggests a new pixel-based embedding scheme. First, the low-quality image but high resolution, magnified into 1 octave above, is acquired using an adaptive 8-directional interpolation based on the high frequency coefficients of the wavelet transform. Thereafter, the pixel embedding process updates a high resolution pixel of the magnified image with the weighted sum of the best matched pixel value, which is searched at its low resolution image. As the results, the proposed scheme is simple and removes zig-zaging effects without any additional process.

• Journal of Korea Multimedia Society
• /
• v.20 no.10
• /
• pp.1655-1661
• /
• 2017

A high-speed directional interpolation algorithm based on the pattern of a $2{\times}2$ pixel block is proposed in this paper. The basic concept of the proposed algorithm is started from UDWT(un-decimated discrete wavelet transform), but there are no transform operations. In order to detect the direction of the edge, 4-pixel differences of two pairs in the $2{\times}2$ block are compared. The $2{\times}2$ block patterns are grouped into total 8 classes, and thereafter the directional interpolation is executed according to the type of the pattern. Since the calculation of the proposed algorithm is very simple and needs a few additions on integer data type, the computation time is almost same as that of bilinear interpolation algorithm. However, experimental results show that the output quality of the proposed one is better than those of the conventional interpolation ones in the objective quality and the computation time.

• Proceedings of the IEEK Conference
• /
• 1999.11a
• /
• pp.780-783
• /
• 1999

This paper gives channel estimation of W-CDMA reverse link using 2-point second-order algorithm over Rayleigh fading channels. The proposed algorithm is compared with the existing interpolation algorithms, i.e., WMSA, linear and second-order Gaussian interpolation, by obtaining HER performance through computer simulations. The BER performance of 2-point second-order interpolation is superior to other algorithms in fading channels. The proposed algorithm also has relatively-simple structure and similar processing delay in comparison to the existing algorithm, Therefore, this algorithm is more suitable for high speed mobile communication environments.

• Communications of the Korean Mathematical Society
• /
• v.22 no.3
• /
• pp.475-485
• /
• 2007

We construct high-degree interpolation rules using not only pointwise values of a function but also of its derivatives up to the p-th order at equally spaced nodes on a closed and bounded interval of interest by introducing a linear functional from which we produce systems of linear equations. The linear systems will lead to a conclusion that the rules are uniquely determined for the nodes. An example is provided to compare the rules with the classical interpolating polynomials.

• Proceedings of the SAREK Conference
• /
• 2007.11a
• /
• pp.29-33
• /
• 2007

In order to protect the environment from the refrigerant pollution, the $CO_2$ may be regarded as one of the most attractive alternative refrigerants for an automotive air-conditioning system. Control methods for a $CO_2$ system should be different because of $CO_2$'s unique properties as a refrigerant. Especially, the high-side pressure of a $CO_2$ system should be controlled for the effective operation of the system. In this study, the high-side pressure setpoint algorithm was developed by using a neural network and a Lagrange interpolation method. These methods were compared. Simulation results showed that a Lagrange interpolation method was more effective than a neural network in the respect of its easiness of programming and shorter execution time.