• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.135-143
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• 1990

In this paper, a new motion detection method using an order-statistic filter is proposed to improve the image quality when the QT subsampling structure is used for reduction of bandwidth of high-resolution TV signals. This new method is applicable to the MUSE system of HDTV and various schemes using the multiple subasmpling with frame-offset for the reduction of bandwidth in highresolution TV signals.

• Investigative Magnetic Resonance Imaging
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• v.23 no.1
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• pp.1-16
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• 2019

Dynamic contrast enhanced (DCE) magnetic resonance (MR) imaging plays an important role in non-invasive detection and characterization of primary and metastatic lesions in the liver. Recently, efforts have been made to improve spatial and temporal resolution of DCE liver MRI for arterial phase imaging. Review of recent publications related to arterial phase imaging of the liver indicates that there exist primarily two approaches: breath-hold and free-breathing. For breath-hold imaging, acquiring multiple arterial phase images in a breath-hold is the preferred approach over conventional single-phase imaging. For free-breathing imaging, a combination of three-dimensional (3D) stack-of-stars golden-angle sampling and compressed sensing parallel imaging reconstruction is one of emerging techniques. Self-gating can be used to decrease respiratory motion artifact. This article introduces recent MRI technologies relevant to hepatic arterial phase imaging, including differential subsampling with Cartesian ordering (DISCO), golden-angle radial sparse parallel (GRASP), and X-D GRASP. This article also describes techniques related to dynamic 3D image reconstruction of the liver from golden-angle stack-of-stars data.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.6
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• pp.127-136
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• 2010

In multi-view video, illumination disharmony between neighboring views can occur on account of different location of each camera and imperfect camera calibration, and so on. Such discrepancy can be the cause of the performance decrease of multi-view video coding by mismatch of inter-view prediction which refer to the pictures obtained from the neighboring views at the same time. In this paper, we propose an efficient histogram-based prefiltering algorithm to compensate mismatches between the luminance and chrominance components in multi-view video for improving its coding efficiency. To compensate illumination variation efficiently, all camera frames of a multi-view sequence are adjusted to a predefined reference through the histogram matching. A Cosited filter that is used for chroma subsampling in many video encoding schemes is applied to each color component prior to histogram matching to improve its performance. The histogram matching is carried out in the RGB color space after color space converting from YCbCr color space. The effective color conversion skill that has respect to direction of edge and range of pixel value in an image is employed in the process. Experimental results show that the compression ratio for the proposed algorithm is improved comparing with other methods.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.10
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• pp.21-31
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• 1994

This paper describes the multichannel combined R2MFC/DTMF/CCT reciver which provides a signaling service functions for call processing control in digital switching system. Using the TMS320C25 DSP chip, we have implemented multi-function receriver shich processes 8 channels of R2MFC, DTMF, and CCT signals simultaneously. In order to increase the channel multiplicity of the combined receiver. R2MFC and CCT receiver were employed by discrete Fourier transform(DFT) method using Goertzel algorithm, and DTMFreceiver was employ by infinite impulse reponse(IIR) filtering method using 4KHz subsampling technique. The combined receiver has 4 function modes for each channel such as R2MFC, DTMF, CCT, and Idle modes. The function mode of each channel may be selected at any time by single-chip micro-controller(.mu.C). Hence, the number of channels assigned for each function mode can be adjusted dynamically according to the signaling traffic variations. From the experimental test results using the test-bed, it has been proved that the combined receiver statisfies all receiver satisfies all receiver specifications, and provides good channel multiplicity and performance, Therefore, it may give a great improvement than existing receiver in cost, reliability, availability, and serviceability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.9
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• pp.1239-1247
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• 1993

Mathematical morphology based on the set theory has been applied to various areas in image processing. In this study, we propose a new pyramid structure for binary images based on the morphological operations. We use a specific class of structuring elements to shrink or expand images, and prove that the whole operations are separable to construct the pyramid. Through a simulation study, we show that the pyramid can be used as a progressive image coding.

• The Korean Journal of Malacology
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• v.17 no.2
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• pp.95-104
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• 2001

To determine optimal conditions for measurement of the clearance rate in feeding experiment of an intertidal bivalve Glauconome chinensis, effects of starvation, extent of mixing at subsampling, and initial prey concentration were assessed. Experiments were conducted separately for each condition with different treatments. Two-way ANOVAs showed that there were significant differences in clearance rates among different starvation periods (p<0.001), extents of mixing (p = 0.005), and prey concentrations (p < 0.001). Starvation for 1 or 2 days gave rise to 2 to 3-fold increase in the clearance rate. After starvation for 5 days, the clearance rate decreased seriously, implying loss of physiological status. It is suggested that animals should be fed during acclimation. The differences of the clearance rates between gentle and vigorous mixings were significant, but the differences were smaller than that among different incubation times. It was found that vigorous mixing is not necessary. The effect of initial prey concentration was great. However, optimal prey concentration could not be determined at any fixed value. Experiments with multiple concentrations of algal prey are recommended. Optimal incubation time for measurement of the clearance rate of G. chinensis was determined to be 2-4 hours.

• ETRI Journal
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• v.31 no.6
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• pp.784-794
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• 2009

We present a full HD (1080p) H.264/AVC High Profile hardware encoder based on fast motion estimation (ME). Most processing cycles are occupied with ME and use external memory access to fetch samples, which degrades the performance of the encoder. A novel approach to fast ME which uses shared multibank memory can solve these problems. The proposed pixel subsampling ME algorithm is suitable for fast motion vector searches for high-quality resolution images. The proposed algorithm achieves an 87.5% reduction of computational complexity compared with the full search algorithm in the JM reference software, while sustaining the video quality without any conspicuous PSNR loss. The usage amount of shared multibank memory between the coarse ME and fine ME blocks is 93.6%, which saves external memory access cycles and speeds up ME. It is feasible to perform the algorithm at a 270 MHz clock speed for 30 frame/s real-time full HD encoding. Its total gate count is 872k, and internal SRAM size is 41.8 kB.

• ETRI Journal
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• v.42 no.2
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• pp.258-271
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• 2020

A correlation exists between luminance samples and chrominance samples of a color image. It is beneficial to exploit such interchannel redundancy for color image compression. We propose an algorithm that predicts chrominance components Cb and Cr from the luminance component Y. The prediction model is trained by supervised learning with Laplacian-regularized least squares to minimize the total prediction error. Kernel principal component analysis mapping, which reduces computational complexity, is implemented on the same point set at both the encoder and decoder to ensure that predictions are identical at both the ends without signaling extra location information. In addition, chrominance subsampling and entropy coding for model parameters are adopted to further reduce the bit rate. Finally, luminance information and model parameters are stored for image reconstruction. Experimental results show the performance superiority of the proposed algorithm over its predecessor and JPEG, and even over JPEG-XR. The compensation version with the chrominance difference of the proposed algorithm performs close to and even better than JPEG2000 in some cases.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.5
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• pp.789-795
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• 2002

Color image is formed of combination of three color channels. Therefore its architecture is very complicated and it requires complicated image Processing for effective image segmentation. In this paper. we propose architecture of universalized Color Morphological Pyramids(CMP) which is able to give effective image segmentation. Image Pyramid architecture is a successive Image sequence whose area ratio $2^{\int}({\int}=1,2,....,N)$ after filtering and subsampling of input image. In this technique, noise removed by sequential filtering and resolution is degraded by downsampling using CMP in various color spaces. After that, new level images are constructed that apply formula using distance of neighbor vectors in close level images and segments its image. The feasibility of proposed method is examined by comparing with the results obtained from the existing method.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2204-2212
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• 2022

Recently, the demand for alpha imaging detectors for quantifying the distributions of alpha particles has increased in various fields. This study aims to reconstruct a high-resolution image from an alpha imaging detector by applying a super-spatial resolution method combined with the maximum-likelihood expectation maximization (MLEM) algorithm. To perform the super-spatial resolution method, several images are acquired while slightly moving the detector to predefined positions. Then, a forward model for imaging is established by the system matrix containing the mechanical shifts, subsampling, and measured point-spread function of the imaging system. Using the measured images and system matrix, the MLEM algorithm is implemented, which converges towards a high-resolution image. We evaluated the performance of the proposed method through the Monte Carlo simulations and phantom experiments. The results showed that the super-spatial resolution method was successfully applied to the alpha imaging detector. The spatial resolution of the resultant image was improved by approximately 12% using four images. Overall, the study's outcomes demonstrate the feasibility of the super-spatial resolution method for the alpha imaging detector. Possible applications of the proposed method include high-resolution imaging for alpha particles of in vitro sliced tissue and pre-clinical biologic assessments for targeted alpha therapy.