• 전기전자학회논문지
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• 제22권3호
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• pp.585-589
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• 2018

Consumer demand for high quality image/video services led to growing trend in image quality enhancement study. Therefore, recent years was a period of substantial progress in this research field. Through careful observation of the image quality after processing by image enhancement algorithms, we perceived that the dark region in the image usually suffered loss of contrast to a certain extent. In this paper, the low-light stretch preprocessing algorithm is, hence, proposed to resolve the aforementioned issue. The proposed approach is evaluated qualitatively and quantitatively against the well-known histogram equalization and Photoshop curve adjustment. The evaluation results validate the efficiency and superiority of the low-light stretch over the benchmarking methods. In addition, we also propose the 255MHz-capable hardware implementation to ease the process of incorporating low-light stretch into real-time imaging systems, such as aerial surveillance and monitoring with drones and driving aiding systems.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권12호
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• pp.4588-4603
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• 2014

In this paper, we present a high-quality image authentication scheme based on absolute moment block truncation coding. In the proposed scheme, we use the parity of the bitmap (BM) to generate the authentication code for each compressed image block. Data hiding is used to authenticate whether the content has been altered or not. For image authentication, we embed the authentication code to quantization levels of each image block compressed by absolute moment block truncation coding (AMBTC) which will be altered when the host image is manipulated. The embedding position is generated by a pseudo-random number generator for security concerned. Besides, to improve the detection ability we use a hierarchical structure to ensure the accuracy of tamper localization. A watermarked image can be precisely inspected whether it has been tampered intentionally or incautiously by checking the extracted watermark. Experimental results demonstrated that the proposed scheme achieved high-quality embedded images and good detection accuracy, with stable performance and high expansibility. Performance comparisons with other block-based data hiding schemes are provided to demonstrate the superiority of the proposed scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권10호
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• pp.3406-3418
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• 2022

Reversible data hiding is an algorithm that has ability to extract the secret data and to restore the marked image to its original version after data extracting. However, some previous schemes offered the low image quality of marked images. To solve this shortcoming, a new reversible data hiding scheme based on pixel value ordering and edge detection mechanism is proposed. In our proposed scheme, the edge image is constructed to divide all pixels into the smooth regions and rough regions. Then, the pixels in the smooth regions are separated into non overlapping blocks. Then, by taking advantages of the high correlation of current pixels and their adjacent pixels in the smooth regions, PVO algorithm is applied for embedding secret data to maintain the minimum distortion. The experimental results showed that our proposed scheme obtained the larger embedding capacity. Moreover, the greater image quality of marked images are achieved by the proposed scheme than that other previous schemes while the high EC is embedded.

• 한국정보과학회논문지:소프트웨어및응용
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• 제34권3호
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• pp.275-302
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• 2007

본 논문은 고품질 텍스트 압축 기능을 지원하는 우수한 정지영상 압축 시스템을 제안한다. 영상에서 텍스트 부분을 분리하여 압축을 수행함으로서 고품질의 텍스트 압축 기능을 지원한다. 시스템은 코드블록 단위로 적응 이진 산술부호화를 수행하여 48:1 이상의 높은 정지영상 압축률을 보여주고 있다. 코드블록은 비트평면을 구성하는 비트들을 서브블록 단위로 파악하여 산술부호에 적합한 코드블록을 구성한 것이다. 산술부호기는 구성된 코드블록을 문맥을 기반으로 압축한다. 시스템의 입력 모드는 분할(Segmentation) 모드와 ROI(Region Of Interest) 모드로 구성된다. 분할 모드는 입력 영상을 텍스트 부분과 배경 영상 부분으로 분할하여 입력할 수 있게 한다. ROI 모드는 입력 영상을 관심 영역과 그 밖의 영역으로 구분하여 입력할 수 있게 한다. 현재 시스템이 나타내는 텍스트 압축 기능과 높은 압축률은 다른 JPEG2000 시스템들과 충분히 비교할 수 있는 수준이다. 시스템은 그 밖에 그레이 코딩을 수행하여 압축률을 향상시킨다.

• 한국가정과학회지
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• 제8권1호
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• pp.5-18
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• 2005

The purposes of this study were to identify brand image and advertising image perception maps of domestic make-up products. A self-administered questionnaire was used for data collection. KYST, CORAN and SPSS PC(Ver. 12.0) were used for data analysis. The results were as follows: 1. Brand images of Etude, Isa Knox, and Laneige were perceived as unique, stimulative, high quality, elegant, modern, and sophisticated. Brand image of Cathycat was perceived highly in high quality, elegant, modern, and sophisticated, but low in unique and stimulative. Brand image of Lac Vert was perceived high in unique and stimulative, but low in high quality, elegant, modern, and sophisticated. Brand images of Hercyna and Vov were the lowest. 2. Advertisement images of Etude was perceived as modern, sophisticated, familiar, and unique, but Lac Vert was perceived adversely, Advertising images of Laneigne and Isa Knox were high in modern, sophisticated and familiar, but low in uniqueness. And advertising images of Hercyna, Cathycat, and Vov were perceived as modern, sophisticated, and familiar.

• Journal of Information Processing Systems
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• 제10권2호
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• pp.256-270
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• 2014

A new morphed steganographic algorithm is proposed in this paper. Image security is a challenging problem these days. Steganography is a method of hiding secret data in cover media. The Least Significant Bit is a standard Steganographic method that has some limitations. The limitations are less capacity to hide data, poor stego image quality, and imperceptibility. The proposed algorithm focuses on these limitations. The morphing concept is being used for image steganography to overcome these limitations. The PSNR and standard deviation are considered as a measure to improve stego image quality and morphed image selection, respectively. The stego keys are generated during the morphed steganographic embedding and extracting process. Stego keys are used to embed and extract the secret image. The experimental results, which are based on hiding capacity and PSNR, are presented in this paper. Our research contributes towards creating an improved steganographic method using image morphing. The experimental result indicates that the proposed algorithm achieves an increase in hiding capacity, stego image quality, and imperceptibility. The experimental results were compared with state of the art steganographic methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권1호
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• pp.395-413
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• 2016

Image authentication is a technique aiming at protecting the integrity of digital images. Reversible image authentication has attracted much attention of researcher because it allows to authenticate tampered regions in the image and to reconstruct the stego image to its original version losslessly. In this paper, we propose a new, reversible image authentication scheme based on adaptive prediction error expansion (PEE) technique. In the proposed scheme, each image block is classified into smooth or complex regions. Then, according to the characteristic of each block, the authentication code is embedded adaptively to achieve high performance of tamper detection. The experimental results demonstrated that the proposed scheme achieves good quality of stego images. In addition, the proposed scheme has ability to reconstruct the stego image to its original version, if no modification is performed on it. Also demonstrated in the experimental results, the proposed scheme provides higher accuracy of tamper detection than state-of-the-art schemes.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제27권1호
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• pp.56-74
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• 2023

In order to obtain practical and high-quality satellite images containing high-frequency components, a large aperture optical system is required, which has a limitation in that it greatly increases the payload weight. As an attempt to overcome the problem, many multi-aperture optical systems have been proposed, but in many cases, these optical systems do not include high-frequency components in all directions, and making such an high-quality image is an ill-posed problem. In this paper, we use deep learning to overcome the limitation. A deep learning model receives low-quality images as input, estimates the Point Spread Function, PSF, and combines them to output a single high-quality image. We model images obtained from three rectangular apertures arranged in a regular polygon shape. We also propose the Modulation Transfer Function Loss, MTF Loss, which can capture the high-frequency components of the images. We present qualitative and quantitative results obtained through experiments.

• 한국멀티미디어학회논문지
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• 제17권10호
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• pp.1205-1212
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• 2014

In this paper, we propose a high-quality stitching method of 3D multiple dental CT images. First, a weighted function is generated using the difference of two distance functions that calculate a distance from the nearest edge of an overlapped region to each position. And a blending ratio propagation function for two gradient vectors is parameterized by the difference and magnitude of gradient vectors that is also applied by the weighted function. When the blending ratio is propagated, an improved region growing scheme is proposed to decide the next position and calculate the blending intensity. The proposed method produces a high-quality stitching image. Our method removes the seam artifact caused by the mean intensity difference between images and vignetting effect. And it removes double edges caused by local misalignment. Experimental results showed that the proposed method produced high-quality stitching images for ten patients. Our stitching method could be usefully applied into the stitching of 3D or 2D multiple images.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.628-630
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• 2003

Synthetic Aperture Radar(SAR) is an active microwave instrument that performs high-resolution observation under almost all weather condition. Research and algorithms have been proposed to process radar signal and to increase the quality of SAR products. In fact, many complicated steps are involved in order to generate a SAR image product. The purpose of this paper is to derive quality assessment procedures and define important test parameters in each procedure inside a SAR processor. Thus those test parameter values indicate the quality of SAR image products and verify the processor's performance. Moreover, required procedures to correct and handle errors which are indicated during the assessment are also presented.