• Current Optics and Photonics
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• v.2 no.2
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• pp.165-171
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• 2018

Fourier ptychographic microscopy (FPM) is a recently proposed computational imaging method that achieves both high resolution (HR) and wide field of view. In the FPM framework, a series of low-resolution (LR) images at different illumination angles is used for high-resolution image reconstruction. On the basis of previous research, image noise can significantly degrade the FPM reconstruction result. Since the captured LR images contain a lot of dark-field images with low signal-to-noise ratio, it is very important to apply a noise-reduction process to the FPM raw dataset. However, the thresholding method commonly used for the FPM data preprocessing cannot separate signals from background noise effectively. In this work, we propose an improved thresholding method that provides a reliable background-noise threshold for noise reduction. Experimental results show that the proposed method is more efficient and robust than the conventional thresholding method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.3
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• pp.757-770
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• 2022

Palmprint recognition has drawn increasingly attentions in the past decade due to its uniqueness and reliability. Traditional palmprint recognition methods usually use high-resolution images as the identification basis so that they can achieve relatively high precision. However, high-resolution images mean more computation cost in the recognition process, which usually cannot be guaranteed in mobile computing. Therefore, this paper proposes an improved low-resolution palmprint image recognition method based on residual networks. The main contributions include: 1) We introduce a channel attention mechanism to refactor the extracted feature maps, which can pay more attention to the informative feature maps and suppress the useless ones. 2) The ResStage group structure proposed by us divides the original residual block into three stages, and we stabilize the signal characteristics before each stage by means of BN normalization operation to enhance the feature channel. Comparison experiments are conducted on a public dataset provided by the Hong Kong Polytechnic University. Experimental results show that the proposed method achieve a rank-1 accuracy of 98.17% when tested on low-resolution images with the size of 12dpi, which outperforms all the compared methods obviously.

• Advances in aircraft and spacecraft science
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• v.10 no.1
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• pp.67-82
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• 2023

Linear array imaging sensors are widely used in remote sensing satellites. The final products of an imaging sensor can only be used when they are geometrically, radiometrically, and spectrally calibrated. Therefore, at the first stages of sensor design, a detailed calibration procedure must be carefully planned based on the accuracy requirements. In this paper, focusing on inherent optical distortion, a step-by-step procedure for laboratory geometric calibration of a typical push-broom satellite imaging sensor is simulated. The basis of this work is the simulation of a laboratory procedure in which a linear imager mounted on a rotary table captures images of a pin-hole pattern at different angles. By these images and their corresponding pinhole approximation, the correction function is extracted and applied to the raw images to give the corrected ones. The simulation results illustrate that using this approach, the nonlinear effects of distortion can be minimized and therefore the accuracy of the geometric position of this method on the image screen can be improved to better than the order of sub-pixel. On the other hand, the analyses can be used to proper laboratory facility selection based on the imaging sensor specifications and the accuracy.

• Journal of Korea Multimedia Society
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• v.15 no.2
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• pp.179-194
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• 2012

Digital image forgery is becoming a topic of great interest with regard to honesty in imaging. We can often see forged digital images in a variety of places, such as the internet, and magazines, and in images used in political ads, etc. These can reduce the reliability and factual basis of the information contained in image. Therefore, objectivity is needed to determine if the image is forged so as to prevent confusion in the viewing public. Most digital forgeries consist of image resizing, rotating including the following interpolations. To find evidence of interpolation in forged images, this paper proposes a new method for detecting digital image forgery using general interpolation factors analyzed through re-interpolation algorithm of the forged images in order to determine the differences in the patterns. Through the re-interpolation algorithm we could detect the forged region and filtering region used image retouching included to interpolation.

• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.526-534
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• 2010

This paper describes an algorithm which merges two HDR pictures taken under different exposure time to display on the LDR devices such as LCD or CRT. The proposed method does not generate the radiance map, but directly merges using the weights computed from the input images. The weights are firstly produced on the pixel basis, and then blended with a Gaussian function. This process prevents some possible sparkle noises caused by radical change of the weights and contributes to smooth connection between 2 image informations. The chrominance informations of the images are merged on the weighted averaging scheme using the deviations of RGB average and their differences. The algorithm is characterized by the feature that it represents well the unsaturated area of 2 original images and the connection of the image information is smooth. The proposed method uses only 2 input images and automatically tunes the whole internal process according to them, thus autonomous operation is possible when it is included in HDR cameras which use double shuttering scheme or double sensor cells.

• Imaging Science in Dentistry
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• v.30 no.4
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• pp.265-274
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• 2000

Purpose: The aims of the present study are to determine the optimum compression rate in terms of file size reduction and diagnostic quality of the images after compression and evaluate the transmission speed of original or each compressed image. Materials and Methods: The material consisted of 24 extracted human premolars and molars. The occlusal surfaces and proximal surfaces of the teeth had a clinical disease spectrum that ranged from sound to varying degrees of fissure discoloration and cavitation. The images from Digora system were exported in TIFF and the images from conventional intraoral film were scanned and digitalized in TIFF by Nikon SF-200 scanner (Nikon, Japan). And six compression factors were chosen and applied on the basis of the results from a pilot study. The total number of images to be assessed were 336. Three radiologists assessed the occlusal and proximal surfaces of the teeth with 5-rank scale. Finally diagnosed as either sound or carious lesion by one expert oral pathologist. And sensitivity, specificity and k value for diagnostic agreement was calculated. Also the area (Az) values under the ROC curve were calculated and paired t-test and oneway ANOVA test was performed. Thereafter, transmission time of the image files of the each compression level was compared with that of the original image files. Results: No significant difference was found between original and the corresponding images up to 7% (1 : 14) compression ratio for both the occlusal and proximal caries (p<0.05). JPEG3 (1 : 14) image files are transmitted fast more than 10 times, maintained diagnostic information in image, compared with original image files. Conclusion: 1 : 14 compressed image file may be used instead of the original image and reduce storage needs and transmission time.

• Journal of the Korean Society of Costume
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• v.64 no.3
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• pp.126-141
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• 2014

The purpose of this study is to analyze the specific mimesis types of common character costumes in MMORPGs, which have stories that are very similar in structure to ancient myths and fantasy novels. As the subject of the research I have selected "Diablo 3" created by the American video game developer, Blizzard Entertainment Images of 5 characters, for both genders - Barbarian, Witch Doctor, Monk, Demon hunter, Wizard - were compiled for a total of 10 images, and these images were compared to popular archetypes in mythology, religion and literature. analyzed them separately according to the mimesis type. For this study, Articles and books containing the Aesthetics, Mimesis and Digital culture were researched in order to study the costume features and the Mimesis types and compare them to the costumes in the MMORPG. Firstly, the character Barbarian is a successor of the barbarian character of the previous product. The outfit worn by the game figure is based on the common images expressed in the movie . The makers created an analogous-imitation mimesis by replicating the image in an exaggerated and grand form. Second, the character Witch Doctor derived its motif from the Voodoo cult, and was expressed in analogous-imitation mimesis, using the very shades and patterns used in real life. Third, the character Monk, blending the image of a priest in Eastern Europe and images of its oriental counterparts, was expressed in transposition-diversion mimesis. Fourth, the Demon Hunter took the source of its inspiration from the image of a Witch hunter in the medieval times. The game character has a sharper sleeker figure than its model, and uses more acute shapes and darker gloomier colors expressed in an analogous-imitation mimesis. Finally, the character Magician took a formless character and expressed it in transposition-diversion mimesis taking as its basis some fantasy novels.

• The Journal of the Korea Contents Association
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• v.12 no.1
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• pp.112-124
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• 2012

The remarkable development of digital technologies and the success of 3D stereoscopic films have led to started drawing attention to stereoscopic images. The stereoscopic images have not become a passing fad in the present time unlike in the past, but have constantly showed their potentials. Unfortunately, the domestic stereoscopic images market is faced with difficulties, such as lack of the capital strength and of insufficient production infrastructure, and the production of 3D from 2D. As a result, it is not easy to produce creative stereoscopic animation contents. Therefore, in Korea, more efforts should be made in accumulating a plenty of data on production techniques. In order to make film production reflecting stereoscopy and effective stereoscopic implementation, which are necessary to produce high-quality stereoscopic contents, this thesis gave an explanation about a production technique studied on the basis of 3D graphic. Stereoscopic images are definitely one of the most promising image contents in the 21st digital contents industry. For the reason, in order to produce stereoscopic animation contents with high quality, fundamental studies on the stereoscopic images should be performed in a constant and cautions way.

• The KIPS Transactions:PartB
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• v.15B no.3
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• pp.205-210
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• 2008

A new approach is proposed for restoration of corrupted regions and segmentation in natural text images. The challenge is to fill in the corrupted regions on the basis of color feature analysis by second order symmetric stick tensor. It is show how feature analysis can benefit from analyzing features using tensor voting with chromatic and achromatic components. The proposed method is applied to text images corrupted by manifold types of various noises. Firstly, we decompose an image into chromatic and achromatic components to analyze images. Secondly, selected feature vectors are analyzed by second-order symmetric stick tensor. And tensors are redefined by voting information with neighbor voters, while restore the corrupted regions. Lastly, mode estimation and segmentation are performed by adaptive mean shift and separated clustering method respectively. This approach is automatically done, thereby allowing to easily fill-in corrupted regions containing completely different structures and surrounding backgrounds. Applications of proposed method include the restoration of damaged text images; removal of superimposed noises or streaks. We so can see that proposed approach is efficient and robust in terms of restoring and segmenting text images corrupted.

• Journal of Science of Art and Design
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• v.4
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• pp.123-146
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• 2002

[ $\lceil$ ]The Life of Pigeons$\rfloor$ consists of seven different canvases without a leading image It contains fragments of disassociated ordinary subjects from a capitalistic and consuming society. In this respect, the text itself attains multiple meanings throughout with inner disharmony, disassociation and relationships of differences. The divided seven images look as if they are connected as one and are connected events that are happening at the same time and in similar places. A liberal interpretation of this work is given to viewers when the seven canvases have both relations and gaps at the same time. $\lceil$The Life of Pigeons$\rfloor$ attempts the viewer's disruption through its middle stratum of meaning structure, which is a device for viewers to rearrange and deeply analyze the seven images. As a result, the artist allows the viewers to get lost in self-contradiction. A fundamental formal structure adopting post-modernism and abandoning modernism is what we can detect with detailed analysis of the work. For instance, changing surface style appears by dividing or putting images in obliquely, furthermore it clearly shows that the main subject is divided in form such as the subject's division into seven spaces. There are three major characteristics. First, the form of the images is divided and composed through oblique and overlapped images. Second, the main content of the subject tends to be scattered. Third, the subjects are interpreted in multiple meanings due to their allegory and symbolism. The inquiry of $\lceil$The Life of Pigeons$\rfloor$ proves that it takes a post artistic spirituality as its basis and its subjects are divided by the differences and surrounding relationships.