• Proceedings of the IEEK Conference
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• summer
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• pp.128-132
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• 2004

In this paper, we propose a new image quality assessment scheme considering the human visual perception characteristics. A subjective quality assessment is obtained by the response of the receptive field in the primary visual cortex and a human's eye can't focus on all of the visual range in a moment. Take advantage of two facts above, we apply Gabor wavelet transform, which is well fit the receptive field in the cortex, to divided constant sized subblocks. Then a local distortion of the subblocks and a global distortion for the entire image are calculated in order. The proposed method has been evaluated using video test sequences provided by the Video Quality Experts Group (VQEG). The experimental results show that good correlation with human perception is obtained using the proposed metric, which is what we called GPSNR.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.433-438
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• 1999

The land use type of Korea is high-density. So, the image classification using coarse resolution satellite image may not provide land cover classification results as good as expected. The purpose of this paper is to compare the result of visual interpretation with that of digital image classification of 20 m resolution SPOT satellite image at Kwangju-eup, Kyunggi-do, Korea. Classes are forest, cultivated field, pasture, water and residential area, which are clearly discriminated in visual interpretation. Maximum likelihood classifier was used for digital image classification. Accuracy assessment was done by comparing each classification result with ground truth data obtained from field checking. The classification result from the visual interpretation presented an total accuracy 9.23 percent higher than that of the digital image classification. This proves the importance of visual interpretation for the area with high density land use like the study site in Korea.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.6
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• pp.84-96
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• 2008

This research investigated the landscape characteristics of the skyline and the cognitive characteristics of Mt. Mudeung (1,186m) from various viewpoints. Mt. Mudeung, the representative landscape of Gwangju City, has been recognized as a natural landmark and theme of paintings. By analyzing the perspective from 32 points with a digital terrain model, some landscape indices of the skyline were derived and the relationships are discussed. Assessment of the semantic differential scale with 21 adjective variables and representativeness to 15 landscape photographs of the mountain were accomplished. 1. Through regression analysis of the skyline indices, significant relationships were found between them the angle from the visual axis and number of skyline jumps, the vertical angle fluctuation and number of jumps per degree, the visual depth fluctuation and vertical angle fluctuation of skyline, and between the vertical angle mean and number of jumps per degree. Meaningful relations were found between the number of jumps of skyline to number of jumps per degree and the angle from visual axis to visual distance. However, in the representative assessment no difference was found on the angle from visual axis of viewpoints. On the other hand, it seemed to relate representativeness with visual clarity based on visual distance. 2. We found 4 factors "familiarity", "fluctuation of skylines", "openness", and "feeling of texture" in the results of factor analysis of semantic differential assessment. When considering the results of assessment for representativeness, adjective words for familiarity and openness seemed to have a close assessment. Specifically, the research showed that the landscape representation was highly assessed in a view which could be seen from the higher parts to the lower part of hills. This result indicates that the management of viewpoints which could get a scene from intermediate to distant, and locating a high elevation is important. 3. In the picturesque expression of Mt. Mudeung, various impressions from the different points, a skyline based on the top of Mt. Mudeung and a mono structure by overlapping hills were common characteristics. These common characteristics were also partially found through the analysis of topographical landscape indices and landscape images. Therefore, the viewpoints for the representative landscape management should be selected in natural or open spaces.

• Journal of the Korea institute for structural maintenance and inspection
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• v.2 no.2
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• pp.151-161
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• 1998

In this study, an attempt is made to apply the concept of fuzzy-bayesian theory to the integrity assessment of RC highway bridge, and uncertainty states are represented in terms of fuzzy sets which define several linguistic variables such as "very good", "good", "average", "poor", "very poor", etc. Especially, the concept of fuzzy conditional probability aids to derive a new reliability analysis which includes the subjective assessment of engineers without introducing any additional correction factors. The fuzzy concept are also used as reliability indexes for the condition assessment based on the proposed models, the proposed fuzzy theory-based approach with the results of visual inspection and extensive field load tests are applied to the integrity assessment of a new RC highway bridge, namely, Jichok bridge.

• Journal of the Korea Society of Computer and Information
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• v.23 no.4
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• pp.41-49
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• 2018

The purpose of this study is to investigate the effect of computer pointing game on the visual perception ability of children with severe intellectual disability. Based on a literature review, we developed a computer pointing game to improve visual perception ability, which consisted of three stages; catching a hamburger, catching a hamburger and a soda, and catching various foods. At each stage, different instructional models were applied by difficulty level of the contents. Experiments were performed among four children with severe intellectual disabilities for three weeks. They belonged to H public school in Kyeonggi, Korea. Their visual perceptions were quantitatively measured four times by utilizing the Korean Developmental Test of Visual Perception tool (K-DTVP-2). For qualitative evaluation, an observation assessment diary was written and analyzed. All four children at the fourth test showed better visual perception ability, compared with the ability at the first test. As a result of the analysis of the observation assessment, they were considered successful in their learning and ordinary life related to visual perception. It can be concluded that the computer pointing game may play a role in helping children with severe intellectual disabilities improve their visual perception ability.

• Journal of the Ergonomics Society of Korea
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• v.20 no.1
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• pp.31-43
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• 2001

The present study the feasibility of the new subjective assessment devise; Real-Time Subjective Assessment Digitizer (RTSAD). The subjects were instructed to evaluate their sensibility during the presentation of the positive and the negative visual stimuli using RTSAD. After the presentation of each of the stimulus, a questionnaire was used for comparing the results with those from RTSAD. It was argued that the biggest utility of the RTSAD is the capability of measuring and figuring out the trends of the subjective assessment in real time. The results from the questionnaires unlike the results from RTSAD, reflects only the averaged human sensibility for the entire time of the presentation of the stimulus.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.12
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• pp.1589-1598
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• 1999

Conventional MSE or PSNR based methods for objective picture quality assessment of moving picture coder are not well correlated with subjective human evaluation. In recent years, the design of better objective quality assessment has attracted much intention and several picture quality metrics based on the properties of Human Visual System has been proposed. This paper proposes new metric which is appropriate for objective picture quality assessment of block based moving picture coder by considering frequency sensitivity, inter-intra channel masking and several distortion artifacts caused by block based coding. The experimental results show that the proposed method is good correlated with subjective assessment.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.5
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• pp.255-265
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• 2013

3DTV is expected to be a promising next-generation broadcasting service. On the other hand, the visual discomfort/fatigue problems caused by viewing 3D videos have become an important issue. This paper proposes a perceptual quality assessment metric for a stereoscopic video (SV-PQAM). To model the SV-PQAM, this paper presents the following features: temporal variance, disparity variation in intra-frames, disparity variation in inter-frames and disparity distribution of frame boundary areas, which affect the human perception of depth and visual discomfort for stereoscopic views. The four features were combined into the SV-PQAM, which then becomes a no-reference stereoscopic video quality perception model, as an objective quality assessment metric. The proposed SV-PQAM does not require a depth map but instead uses the disparity information by a simple estimation. The model parameters were estimated based on linear regression from the mean score opinion values obtained from the subjective perception quality assessments. The experimental results showed that the proposed SV-PQAM exhibits high consistency with subjective perception quality assessment results in terms of the Pearson correlation coefficient value of 0.808, and the prediction performance exhibited good consistency with a zero outlier ratio value.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.4
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• pp.1-13
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• 1999

Previous research for visual assessment of streetscape employed static simulation methods to represent future landscape. However, streetscape is experienced sequentially, and thus dynamic simulations can be more effective. This study tried to adopt computer animation in the evaluation of streetscape, and examined its effects and possibilities. Three development scenarios for the redevelopment districts of Sokong-Ro and Banpo-Ro in Seoul were designed, and simulations were produced by three methods-photo-retouching, computer still image, and animation. A preference questionnaire was asked to 69 university students, and the effects of simulation methods on visual preference were examined. In addition, the frames of the animation were reclassed to identify the visibility of physical elements. The relationships between the visibility and visual preference were analyzed. The results showed that visual preference can be explained by three factors-Amenity, Tidiness, and Variousness-that account for 62.4% of the total variance, and the Amenity showed the highest proportion: 36.0%. Among the three simulation methods, animation showed the largest difference in preference for the most important factor(Amenity), and yielded the highest correlation between visibility of physical elements and Amenity. This result demonstrated that dynamic simulations can provide more accurate observation of visual changes, especially because the simulated landscape is experienced sequentially. The results also revealed that the sequential change in the visibility of physical elements can be examined easily and precisely by animation. This benefit of animation enables analysts to identify the points where the landscape varies the most, and thus visual preference should be evaluated.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.4
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• pp.205-213
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• 2001

The condition assessment of bridges is one of the important procedures in the safety evaluation of the structures. The current inspection guideline is rather ambiguous and vague so that the inspection results based on the existing guidelines are highly subjective and varing from person to person and even day to day for a given person. It is therefore, necessary to improve the current inspection criteria in order to provide consistent results in safety assessment. To circumvent possible inconsistencies in inspection and rating of bridge components, the revised criteria have been proposed in this study. The proposed guideline and criteria may be efficiently used for the realistic and consistent assessment of bridge structures.