• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2403-2408
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• 2015

For image data the discrete cosine transform (DCT) has comparable energy compaction capability to Karhunen-Loeve transform (KLT) which is optimal. Hence DCT has been widely accepted in various image and video compression standard such as JPEG, MPEG-2, and MPEG-4. Recently some approximate DCT's have been reported, which can be computed much faster than the original DCT because their coefficients are either zero or the power of 2. Although the level of energy compaction is slightly degraded, the approximate DCT's can be utilized in real time implementation of image or visual compression applications. In this paper, an approximate 8-point DCT which contains 17 non-zero power-of-2 coefficients and high energy compaction capability comparable to DCT is proposed. Transform coding experiments with several images show that the proposed transform outperforms the published works.

• Journal of Broadcast Engineering
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• v.13 no.4
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• pp.489-500
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• 2008

We propose a novel high-definition content watermarking algorithm that is highly feasible in UCC (User Created Contents) environment. We begin by addressing an association between broadcasting content and UCC in a view of copyrights, then present watermark requirements by analyzing various UCC editing-effect. Also, we provide a brief review of previous watermarking techniques that are supposed to satisfy the requirements. Our proposed scheme inserts a invisible watermark into both DC and AC components on $8{\times}8$ block DCT domain and extracts them after synchronization using DC image. Experimental results show that our technique satisfies the requirements of invisibility and robustness to a variety of attacks such as rotation, scaling, cropping, and JPEG compression, etc. Note that the proposed scheme is highly resilient to UCC edit attacks that are combined by many different types of watermark attacks.

• Journal of Korean Society for Geospatial Information Science
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• v.18 no.1
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• pp.55-61
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• 2010

As digital images combined with various types of information became popular, the development of transmission format standard for effective application of imageries is demanded. The purpose of the format standard is to provide a universal format that facilitates the exchange of images and related information. In this paper, we found optimal requirements of imagery transmission format standard after reviewing current state of both military and commercial products and studying functions of various types of format standards including NITF (National Imagery Transmission Format). In addition, future research direction of the imagery transmission format standard that complies with current trend of high-resolution and mass storage imagery data is proposed.

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.191-195
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• 2011

The present study was conducted to examine the reactive oxygen species (ROS) generation levels in porcine parthenogenetic embryos. Porcine in vitro matured oocytes were activated by the combination of electric stimulus and 6-DMAP before in vitro culture. Porcine oocytes and parthenogenetic embryos were stained in 10 ${\mu}M$ dichlorohydrofluorescein diacetate (DCF) or 10 ${\mu}M$ hydroxyphenyl fluorescein (HPF) dye each for 30 min at $39^{\circ}C$. The fluorescent emissions from the samples were recoded as JPEG file and the intensity of fluorescence in oocytes and embryos were analyzed. $H_2O_2$ and $^{\cdot}OH$ radical levels of porcine oocytes were reduced immediately after electric stimulation. However, $H_2O_2$ and $^{\cdot}OH$ radical levels of parthenogenetic embryos were increased with time elapsed after electric stimulation from 0 h to 3 h and after DMAP culture. During in vitro culture, $H_2O_2$ and $^{\cdot}OH$ radical levels were gradually increased from the one-cell stage to the two- and four-cell stages. The result of the present study suggests that the ROS was not increased by electric pulse in porcine embryos. Rather than it seems to be associated with the stage of development and the culture condition.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.109-113
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• 2007

The COMS provides the LRIT/HRIT services to users. The COMS LRIT/HRIT broadcast service should satisfy the 15 minutes timeliness requirement. The requirement is important and critical enough to impact overall performance of the LHGS. HRIT image data is acquired from INRSM output receiving but LRIT image data is generated by sub-sampling HRIT image data in the LHGS. Specially, since LRIT is acquired from sub-sampled HRIT image data, LRIT processing spent more time. Besides, some of data loss for LRIT occurs since LRIT is compressed by lossy JPEG. Therefore, algorithm with the fastest processing speed and simplicity to be implemented should be selected to satisfy the requirement. Investigated sub-sampling algorithm for the LHGS were nearest neighbour algorithm, bilinear algorithm and bicubic algorithm. Nearest neighbour algorithm is selected for COMS LHGS considering the speed, simplicity and anti-aliasing corresponding to the guideline of user (KMA: Korea Meteorological Administration) to maintain the most cloud itself information in a view of meteorology. But the nearest neighbour algorithm is known as the worst performance. Therefore, it is studied in this paper that the selection of nearest neighbour algorithm for the LHGS is reasonable. First of all, characteristic of 3 sub-sampling algorithms is studied and compared. Then, several sub-sampling algorithm were applied to MTSAT-1R image data corresponding to COMS HRIT. Also, resized image was acquired from sub-sampled image with the identical sub-sampling algorithms applied to sub-sampling from HRIT to LRIT. And the difference between original image and resized image is compared. Besides, PSNR and MSE are calculated for each algorithm. This paper shows that it is appropriate to select nearest neighbour algorithm for COMS LHGS since sub-sampled image by nearest neighbour algorithm is little difference with that of other algorithms in quality performance from PSNR.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.4
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• pp.1248-1266
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• 2012

This paper presents a multilevel reversible data hiding method based on histogram shifting which can recover the original image losslessly after the hidden data has been extracted from the stego-image. The method of prediction is adopted in our proposed scheme and prediction errors are produced to explore the similarity of neighboring pixels. In this article, we propose two different predictors to generate the prediction errors, where the prediction is carried out using the center prediction method and the JPEG-LS median edge predictor (MED) to exploit the correlation among the neighboring pixels. Instead of the original image, these prediction errors are used to hide the secret information. Moreover, we also present an improved method to search for peak and zero pairs and also talk about the analogy of the same to improve the histogram shifting method for huge embedding capacity and high peak signal-to-noise ratio (PSNR). In the one-level hiding, our method keeps image qualities larger than 53 dB and the ratio of embedding capacity has 0.43 bpp (bit per pixel). Besides, the concept with multiple layer embedding procedure is applied for obtaining high capacity, and the performance is demonstrated in the experimental results. From our experimental results and analytical reasoning, it shows that the proposed scheme has higher PSNR and high data embedding capacity than that of other reversible data hiding methods presented in the literature.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.2
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• pp.97-103
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• 2010

In this paper, we propose a new digital watermarking technique. The main idea of the proposed algorithm relies on the assumption that any real number can be expressed as a summation of the exponential form with base of 2 and if only consider the first few summations some numbers can be expressed in the same form. Therefore, we can be sure that some amount of changes does not affect the first few summations. The algorithm decomposes a host image in wavelet domain and intensity of the significant wavelet coefficient is expressed in exponential form with base of 2. Multiple barcode watermarks are then embedded by modifying the parity of the exponent. The proposed scheme is semi-blind and also offers either objective or subjective deteew su as well. From extracted watermarks, more accurate watermark is obtained by merging technique as a final watermark. As a simulation result, the proposed algorithm could resist most cases of salt and pepper noise, Gaussian noise and JPEG compression.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.11C
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• pp.1118-1122
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• 2003

In this paper, we propose a new invisible digital watermarking scheme based on wavelet transform using singular value decomposition. Embedding process is started by decomposing the lowest frequency band image with 3${\times}$3 block among which we define the watermark block chosen by a key set; entropy and condition number of the block. A watermark is embedded in the singular values of each watermark blocks. This provides a robust watermarking in lowest possible time-frequency domain. To detect the watermark, we are locally modeling an attack as 3${\times}$3 matrices on the watermark blocks. Combining with the SVD and the attack matrices, we estimate watermark set corresponding to the watermark blocks. In each watermark block, we determine an optimal watermark which is justified by the T-testing. A numerical experiment shows that the proposed watermarking scheme efficiently detects the watermarks from several JPEG attacks.

• Journal of Internet Computing and Services
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• v.2 no.4
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• pp.101-109
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• 2001

In recent year, the use of digital picture information and general picture information has been increased, However, numerous copyright infringement and pirate copy of picture information through Internet and CD-ROM happen very often, As a result, several methods of watermarking have been presented to solve and verify distortion of the original data, In addition, watermark data have been suggested to resolve the vastness of the original data, Watermarking methods are often used to protect the right of ownership of a copyright, However, these Watermarking methods have brought the obscurity of recognition caused by the complexity of verification procedure and the increase of magnitude computation occurrence, This paper mainly mentions about the local optimization of scaling parameter, the maximization of hiding of Watermark information and maximization of watermark information in case of restoration that determine the amount of inserted information which is used for preventing distortion and transformation of the original data caused by insertion and hiding of Watermark information on compounding Autostereogram into JPEG picture information.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.343-350
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• 2005

During the design of a successful digital watermarking systems, Pseudo-Noise(PN) sequences are widely used to modulate information bits into watermark signals. In this method, the number of bits that can be hidden within a small image by means of frequency domain watermarking is limited. In this paper, we show the possibility of introducing chaotic sequences into digital watermarking systems as potential substitutes to commonly used PN-sequences. And we propose a method that transforms the text to chaotic sequence. In our current implementation, we show how the sample text is expressed by an implied unit data(watermark) and the implied unit data is regenerated into the original left. Because we use this implied data as watermark for information hiding, we can insert much more watermark compared with previous method.