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

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5A
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• pp.618-633
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• 2000

In this paper, a Gaussian interpolation filter and cubic interpolation filter are presented to do more accurate channel estimation compared to the conventional linear interpolation filter for COFDM systems. In addition to an interpolation filter, a low pass filter using FFT and IFFT is also presented to reduce the noisy components of a channel estimate obtained by an interpolation filter. Channel estimates after low-pass filtering combined with interpolation filters can lower the error floor compared to the use of only interpolation filters. Computer simulation demonstrates that the presented channel estimation methods exhibit an improved performance compared to the conventional linear interpolation filter for COFDM systems in time-varying multipath fading channel and0.1 ~ 0.2 dB of Eb/No difference at BER=10-4 when the perfect channel estimation is compared.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.2
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• pp.253-258
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• 2012

A computationally efficient interpolation filter with a low-distortion performance is a key component to utilize the naturally-sampled pulse width modulation (NPWM) in a digital domain. To realize the efficient interpolation filter, we propose a novel design based on the recently-proposed modified Farrow filter. The proposed filter shows a better pass-band distortion performance maintaining similar degree of complexity compared with the conventional Lagrange interpolation filter. We achieve the maximum distortion deviation of 10-3 dB to 20-kHz audible frequency range and distortion reduction of 1/6 times compared with the Lagrange interpolation filter.

• Journal of Broadcast Engineering
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• v.16 no.3
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• pp.501-509
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• 2011

In this paper, we propose an edge profile adaptive bi-directional diffusion interpolation method which consists of shock filter and level set. In recent years many interpolation methods have been proposed but all methods have some degrees of artifacts such as blurring and jaggies. To solve these problems, we adaptively apply shock filter and level set method where shock filter enhances edge along the normal direction and level set method removes jaggies artifact along the tangent direction. After the initial interpolation, weights of shock filter and level set are locally adjusted according to the edge profile. By adaptive coupling shock filter with level set method, the proposed method can remove jaggies artifact and enhance the edge. Experimental results show that the average PSNR and MSSIM of our method are increased, and contour smoothness and edge sharpness are also improved.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.93-96
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• 2000

This paper has been proposed an audio DAC structure composed of FIRs and IIR filters as digital interpolation filter to integrate the off-chip analog low-pass filter on-a-chip. The passband ripple(< 0.41${\times}$fs), passband attenuation(at 0.41${\times}$fs) and stopband attenuation(> 0.59${\times}$fs) of the Δ$\Sigma$ modulator output using the proposed digital interpolation filter had ${\pm}$ 0.001 ［㏈］, -0.0025［㏈］ and -75［㏈］, respectively. Also the inband group delay was 30.07/fs［s］ and the error of group delay was 0.1672%. Also, the attenuation of stopband has been increased -20［㏈］ approximately at 65［㎑］, out-of-band. Therefore the RC products of analog low-pass filter on chip have been decreased compared with the conventional digital interpolation filter structure.

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

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.8A
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• pp.771-778
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• 2002

We investigate the design of an interpolation filter of a MF-TDMA demodulator which is applied to DVB-RCS. If sampling is not synchronized to the data symbols, timing adjustment in digital receiver must be performed by interpolation. It is impossible that conventional sinc interpolation filter coefficients are actually extended to infinity. We propose a Kaiser window interpolation filter and a sinc interpolation filter using th Kaiser window. Simulation results show that the performance improvement is realized by employing the proposed interpolation filter.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.119-124
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• 2011

Interpolation filters are widely used in many communication and multimedia applications. Polynomial interpolation computes the coefficients of the polynomial according to the input information to obtain the interpolated value. Recently, FIR interpolation method using supplementary filters was proposed to improve the performances of polynomial interpolation methods. In this paper, by combining a weighting factor approach with the supplementary filter method, we propose a weighted interpolation method which can be efficiently used to compute the maximum or minimum values of a given curve using only a restricted number of sample values. With application to the interpolation of normal distribution curves used in XRF systems, it is shown that the proposed approach exhibits improved performances compared with conventional interpolation methods.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.274-279
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• 2009

H.264 suggests applying a 2-D 6-tap wiener filter to realize the interpolation for half-pixel positions, followed by a bilinear interpolation to get the data of quarter-pixels precision. This method is comparatively simpler; however, it only considers the affection of 4-connection neighborhood ignoring the influence that comes from the changing rate between respective neighborhoods. As a result, it has the characteristics of a Low-pass filter under the risk of losing high-frequency weights. The Cubic interpolation uses the gray-values within the larger regions of points to be sampled for interpolation. Nevertheless, the cubic interpolation is more complicated and computational. We give a deep analysis on the features while applying both bilinear and cubic interpolation in H.264 presenting a proper selection of interpolation algorithm with respect to specific distribution of gray-value in a certain grand block. The experiments point out that load far motion searching and interpolation are reduced when promoting the precision of interpolation simultaneously.

• Journal of Broadcast Engineering
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• v.16 no.4
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• pp.624-634
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• 2011

Recently, the JCT-VC is developing the next generation video coding standard that is called HEVC. HEVC has adopted many coding technologies increasing coding efficiency. For chroma interpolation, DCT-based interpolation filter showing better performance than the linear filter in H.264/AVC was adopted in HEVC. In this paper, a combined filter that utilizes the FIR filter and the linear filter in H.264/AVC is proposed to increase coding efficiency. When the proposed method is compared with DCT-based interpolation filter, the experimental results for various sequences show that the average BD-rate improvements on chroma U and V components are 0.9% and 1.1%, respectively, in the high efficiency case of random access structure, those on U and V components are 1.1% and 1.1%, respectively, in the low complexity case of random access structure, those on U and V components are 0.9% and 1.4%, respectively, in the high efficiency case of low delay structure, and those on U and V components are 1.8% and 1.8%, respectively, in the low complexity case of low delay structure.