• Journal of Korea Society of Industrial Information Systems
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• v.20 no.5
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• pp.53-60
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• 2015

In this paper, the DCT based lossless image compression system which selects a limited number of DCT coefficients is proposed for the Lenna, Camerman, and Baboon image. The number of DCT coefficients to obtain a suitable image quality for the reconstructed image is computed by simulation. The image size of $256{\times}256$ are used in the experiment. The PSNR values for the reconstructed image by selecting limited number of DCT coefficients are found. It is shown that the minimun number of the coefficients for Lenna, Cameramen Baby and Babbo image to obtain PSNR=30 are N=16, 32, 37, 55, respectively. The result can provide the guideline of the importance of the DCT coefficient toward the compression for the tested image of the Lena, Cameraman, and Baboon.

• ETRI Journal
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• v.39 no.5
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• pp.683-694
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• 2017

Several studies have focused on multimedia transmission over wireless sensor networks (WSNs). In this paper, we propose a comprehensive and robust model to transmit images over cognitive radio WSNs (CRWSNs). We estimate the spectrum sensing frequency and evaluate its impact on the peak signal-to-noise ratio (PSNR). To enhance the PSNR, we attempt to maximize the number of pixels delivered to the receiver. To increase the probability of successful image transmission within the maximum allowed time, we minimize the average number of packets remaining in the send buffer. We use both single- and multi-channel transmissions by focusing on critical transmission events, namely hand-off (HO), No-HO, and timeout events. We deploy our advanced updating method, the dynamic parameter updating procedure, to guarantee the dynamic adaptation of model parameters to the events. In addition, we introduce our ranking method, named minimum remaining packet best channel selection, to enable us to rank and select the best channel to improve the system performance. Finally, we show the capability of our proposed image scrambling and filtering approach to achieve noticeable PSNR improvement.

• Journal of the Korea Society of Computer and Information
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• v.18 no.2
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• pp.49-57
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• 2013

To improve the quality of magnified image, two schemes were proposed. The one is used to estimate simple convex surface and simple concave surface using the information of adjacent pixel values, and the other scheme is used to produce magnified image using the characteristics of simple convex surface and simple concave surface. The magnified image using the proposed scheme is more similar to real image than the magnified image using the previous schemes. The PSNR values of the magnified images using the proposed scheme are greater than those of the magnified images using the previous interpolation schemes.

• Journal of information and communication convergence engineering
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• v.10 no.3
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• pp.315-320
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• 2012

In H.264/AVC, the first frame of a group of pictures (GOP) is encoded in intra mode which generates a large number of bits. The number of bits for the I-frame affects the qualities of the following frames of a GOP since they are encoded using the bits remaining among the bits allocated to the GOP. In addition, the first frame is used for the inter mode encoding of the following frames. Thus, the initial quantization parameter (QP) affects the following frames as well as the first frame. In this paper, an adaptive peak signal to noise ratio (PSNR)-based initial QP determination algorithm is presented. In the proposed algorithm, a novel linear model is established based on the observation of the relation between the initial QPs and PSNRs of frames. Using the linear model and PSNR results of the encoded GOPs, the proposed algorithm accurately estimates the optimal initial QP which maximizes the PSNR of the current GOP. It is shown by experimental results that the proposed algorithm predicts the optimal initial QP accurately and thus achieves better PSNR performance than that of the existing algorithm.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.392-397
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• 2000

An Interlaced 2D field images compression technique by Discrete Wavelet Transform is proposed. The result has a good image resolution and compression rate, PSNR, and reduces processing time of compression. PSNR depends on the exponential function corresponding to 2 power N has higher 30% than DCT. And It is easier to process the inter-frame and fast to work a second with each parallel field processing, and more be able to approximate a frame on the field.

• Journal of Broadcast Engineering
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• v.10 no.2
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• pp.149-155
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• 2005

We have proposed an objective evaluation method using ESNR as the measure of approximation by the visual model, which coincides with MOS, a subjective evaluation method. For two-value images, we have used five kinds of modulation methods: 1) ordered dither, 2) least mean error, 3) pulse density low division, 4) simple two-value, and 5) random dither methods. The purpose of this paper is to investigate the validity of ESNR, by comparing the proposed method together with the existing representative methods such as PSNR and WSNR, with the subjective method MOS. The results of a series of experiments show that the ranking by MOS coincides with ESNR, though does not coincides with PSNR and WSNR.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.11a
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• pp.222-225
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• 2002

The watermarking on medical images with wavelet packet is presented. The wavelet packet produces the enhancing the resolution from low to high band that minimize the loss on the band. The result on experiment is that PSNR is 0.1dB on image quality and PSNR is 28dB on the durability in compressed ratio 60% over. This proposal allows an enhancing and robust image to stand and oppose the distortion and modification by intention.

• Convergence Security Journal
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• v.2 no.1
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• pp.35-47
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• 2002

In this paper, we will provide an overview of the motion picture watermarking techniques. We will see previously proposed algorithms such as compressed domain watermarking, non-compressed domain watermarking and algorithms for realtime applications etc. We will see test results for signature embedding in motion picture. By spread spectrum method, we embed a signature in each frames. The quality of watermarked motion picture is measured by PSNR(peak signal to noise ratio) about several strengths of watermark. In watermark detection the sign of the correlation sum is the estimated embedded signature bits. We will see different mean PSNR with visual shape of the detected signature.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.147-154
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• 2020

In this study, four types of composite added filtration (aluminum, nickel, copper, and zinc) were combined for each thickness to evaluate dose reduction and optimal images due to X-ray attenuation. To evaluate dose and image quality. X-ray generators, Dose Area Product(DAP) and ICY programs with RQR9 standard quality were used. In the image quality evaluation element (PSNR, RMSE, SSIM), only images with PSNR value of 30 dB or more were analyzed. As a result, the best combination in dose evaluation was 3 mmAl + 0.6 mmNi (0.16µGy㎡), and the best filter in image quality evaluation was 0.9 mmAl (PSNR 34.24dB, RMSE 79.52, SSIM 0.24). In this study, the dose aspect and the image quality aspect are mentioned, So it is considered that further studies on patient's exposure dose and optimal image will be needed in the future.

• Journal of Korea Multimedia Society
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• v.15 no.4
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• pp.526-539
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• 2012

This paper proposes a high capacity data hiding method using high frequence secret data indexing algorithm. Many novel data hiding methods based on LSB and PVD methods were presented to enlarge hiding capacity and provide an imperceptible quality. In this paper, first, calculating data iteration frequency of the secret message and make up the high frequency data index matrix (HFDT) using high frequence data's location information. Next, HFDT uses to that data hiding process on the cover image and recovering process on the stego image. The experimental results demonstrate the efficiency of the proposed high frequency secret data indexing method. For the data hiding method, experiments are conducted for four cases: 2 pattern secret data (2PD), 4 pattern secret data (4PD), 8 pattern secret data (8PD) and higher pattern secret data (HPD). When comparing the proposed method with other data hiding methods, for the HPD case, the results show that the proposed method has a good PSNR and more capacity, and for the other case, the results show that the proposed method has a higher PSNR and larger capacity.