• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1823-1825
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• 2005

In this paper, we propose the system that can monitor and control the camera in the remote place using the PDA. The server PC attached to the PLC(Programmable Logic Controller) acquires the current status(On/Off) of the devices through the RS-232 serial communications. Also, the moving image frames captured from the wireless camera is compressed in the JPEG format and is stored in the server. The PDA, which is connected to the server through wireless internet, receives the data about the status of the devices and controls the devices according to the circumstances of them. Also, it can receive the images from the server simultaneously. So, we can monitor and control the specified area in the remote place using the PDA through the wireless communication.

• Journal of Korea Multimedia Society
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• v.25 no.5
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• pp.676-684
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• 2022

As realistic media are widespread in various image processing areas, image or video compression is one of the key technologies to enable real-time applications with limited network bandwidth. Generally, image or video compression cause the unnecessary compression artifacts, such as blocking artifacts and ringing effects. In this study, we propose a Deep Residual Channel-attention Network, so called DRCAN, which consists of an input layer, a feature extractor and an output layer. Experimental results showed that the proposed DRCAN can reduced the total memory size and the inference time by as low as 47% and 59%, respectively. In addition, DRCAN can achieve a better peak signal-to-noise ratio and structural similarity index measure for compressed images compared to the previous methods.

• Journal of Information Processing Systems
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• v.19 no.2
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• pp.232-239
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• 2023

Aiming at the poor compression quality of traditional image compression coding (ICC) algorithm, a multi-description ICC algorithm based on depth learning is put forward in this study. In this study, first an image compression algorithm was designed based on multi-description coding theory. Image compression samples were collected, and the measurement matrix was calculated. Then, it processed the multi-description ICC sample set by using the convolutional self-coding neural system in depth learning. Compressing the wavelet coefficients after coding and synthesizing the multi-description image band sparse matrix obtained the multi-description ICC sequence. Averaging the multi-description image coding data in accordance with the effective single point's position could finally realize the compression coding of multi-description images. According to experimental results, the designed algorithm consumes less time for image compression, and exhibits better image compression quality and better image reconstruction effect.

• Journal of radiological science and technology
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• v.28 no.4
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• pp.293-299
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• 2005

In the present investigation, we analyzed the data of 1,318 patients (2,636 images) who underwent mammographic examinations and obtained the distribution of the patient age and compressed breast thickness. We measured also average glandular doses (AGD) as function of compressed breast thickness. In order to obtain the values of AGD, we measured half value layer (HVL) and tube output (mR/mAs) for each kVp and target/filter combination. Entrance surface air kerma (ESAK) was calculated from the tube output as measured for each voltage used under clinical conditions and from the tube loading (mAs). AGD per exposure were calculated by multiplying the ESAK values by the conversion factors tabulated by Dance. We obtained in this study the following conclusions. The mean value of compressed breast thickness for cranio-caudal (CC) view was 35.8mm and that for medio-lateral oblique (MLO) view was 43.3 mm. The mean value of AGD for CC view was 1.55 mGy and that for MLO view was 1.70 mGy. The AGD for MLO view was 0.15 mGy (10%) higher than that for CC view because the thickness for MLO view was on average 4.8 mm higher than that for CC view. The values of AGD increased with increasing compressed brest thickness. The increased AGD value was on average 0.34 mGy per 10 mm in the thickness ranges $10{\sim}80\;mm$, therefore differences between the AGD values of each thickness were relative large. Thus, it is considered to need limited doses for mammography with the upper end of exposure range at several different compressed brest thickness.

• Journal of Korea Multimedia Society
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• v.8 no.8
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• pp.1069-1079
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• 2005

Though there have been many methods to detect features in spatial domain, in the case of a compressed image it has to be decoded, processed and encoded again. Alternatively, we can manipulate a compressed image directly in the Discrete Cosine Transform (DCT) domain that has been used for compressing videos or images in the standards like MPEG and JPEG. In our previous work we proposed a model-based discontinuity evaluation technique in the DCT domain that had problems in the rotated or non-ideal discontinuities. In this paper, we propose a fuzzy filtering technique that consists of height fuzzification, direction fuzzification, and forty filtering of discontinuities. The enhancement achieved by the fuzzy tittering includes the linking, thinning, and smoothing of discontinuities in the DCT domain. Although the detected discontinuities are rough in a low-resolution image for the size (8${\times}$8 pixels) of the DCT block, experimental results show that this technique is fast and stable to enhance the qualify of discontinuities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.206-212
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• 2006

Many image and video compression algorithms work by splitting the input image into blocks and producing variable-length coded bits for each block data. If variable-length coded data are transmitted consecutively, then the resulting coder is highly sensitive to channel errors. Therefore, most image and video techniques for providing some protection to the stream against channel errors usually involve adding a controlled amount of redundancy back into the stream. Such redundancy might take the form of resynchronization markers, which enable the decoder to restart the decoding process from the known state, in the event of transmission errors. The Error Resilient Entropy Code (EREC) is a well known method which can regain synchronization without any redundant information to convert from variable-length code to fixed-length code. This paper proposes an enhancement to EREC, which greatly improves its transmission ability for the compressed image quality without any redundant bits in the event of errors. The simulation result shows that the both objective and subjective quality of transmitted image is enhanced compared with the existing EREC at the same BER(Bit Error Rate).

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.1
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• pp.84-89
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• 2019

JPEG is a most widely used standard image compression technology. This research introduces the JPEG image compression algorithm and describes each step in the compression and decompression. Image compression is the application of data compression on digital images. The DCT (discrete cosine transform) is a technique for converting a time domain to a frequency domain. First, the image is divided into 8 by 8 pixel blocks. Second, working from top to bottom left to right, the DCT is applied to each block. Third, each block is compressed through quantization. Fourth, the matrix of compressed blocks that make up the image is stored in a greatly reduced amount of space. Finally if desired, the image is reconstructed through decompression, a process using IDCT (inverse discrete cosine transform). The purpose of this research is to review all the processes of image compression / decompression using the discrete cosine transform method.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.5
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• pp.327-334
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• 2009

The tiled-display system provides a high resolution display which can be used in different applications in co-working area. The systems used in the co-working field usually save the user logs, and these log information not only makes the maintenance of the tiled-display system easier, but also can be used to check the progress of the co-working. There are three main steps in the proposed tiled display log recorder. The first step is to capture the screen shots of the tiles and send them for merging. The second step is to merge the captured tile images to form a single screen shot of the tiled-display. The final step is to encode the merged tile images to make a compressed video stream. This video stream could be stored for the logs of co-working or be streamed to remote users. Since there could be differences in capturing time of tile images, the quality of merged tiled-display could be degraded. This paper proposes a time stamp-based metric to evaluate the quality of the video stream, and a merging algorithm that could upgrade the quality of the video stream with respect to the proposed quality metrics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2586-2594
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• 2009

A digital watermarking technique used as a protection and certifying mechanism of copyrighted creations including music, still images, and videos in terms of finding any loss in data, reproduction and pursuit. This study suggests using a selected geometric invariant point through the whole processing procedure of an image and inserting and extracting based on the invariant point so that it will be robust in a geometric transformation attack. The introduced algorithm here is based on a watershed splitting method in order to make medical images strong against RST(Rotation Scale, Translation) transformation and other processing. It also helps to maintain the watermark in images that are compressed and stored for a period of time. This algorithm also proved that is has robustness against not only JPEG compression attack, but also RST attack and filtering attack.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.435-449
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• 2023

The state-of-the-art video-based point cloud compression(V-PCC) has a high efficiency of compressing 3D point cloud by projecting points onto 2D images. These images are then padded and compressed by High-Efficiency Video Coding(HEVC). Pixels in padded 2D images are classified into three groups including origin pixels, padded pixels and unoccupied pixels. Origin pixels are generated from projection of 3D point cloud. Padded pixels and unoccupied pixels are generated by copying values from origin pixels during image padding. For padded pixels, they are reconstructed to 3D space during geometry reconstruction as well as origin pixels. For unoccupied pixels, they are not reconstructed. The rate distortion optimization(RDO) used in HEVC is mainly aimed at keeping the balance between video distortion and video bitrates. However, traditional RDO is unreliable for padded pixels and unoccupied pixels, which leads to significant waste of bits in geometry reconstruction. In this paper, we propose a new RDO scheme which takes 3D-Distortion into account instead of traditional video distortion for padded pixels and unoccupied pixels. Firstly, these pixels are classified based on the occupancy map. Secondly, different strategies are applied to these pixels to calculate their 3D-Distortions. Finally, the obtained 3D-Distortions replace the sum square error(SSE) during the full RDO process in intra prediction and inter prediction. The proposed method is applied to geometry frames. Experimental results show that the proposed algorithm achieves an average of 31.41% and 6.14% bitrate saving for D1 metric in Random Access setting and All Intra setting on geometry videos compared with V-PCC anchor.