• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.475-476
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• 2018

In this paper, we propose a method to measure the number of biofouling attached to underwater structures. This method measures the number of biofouling based on digital images captured in underwater. The number of biofouling was measured after correcting the image quality of underwater images for accurate population counting. In order to measure the number of biofouling, Maxima value in the image was found.

• The Journal of the Korea Contents Association
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• v.18 no.2
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• pp.178-187
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• 2018

This study aimed to develop a model of the program for automation measuring the preference of the portraits based on the relationship between the image quality factors and the preferences in the portraits for manufacturers aiming at high utilization of the users. in order to proceed with the evaluation, the image quality measurement was divided into objective and subjective items, and the evaluation was done through image processing and statistical methods. the image quality measurement items can be divided into objective evaluation items and subjective evaluation items. RSC Contrast, Dynamic Range and Noise were selected for the objective evaluation items, and the numerical values were statistically analyzed and evaluated through the program. Exposure, Color Tone, composition of person, position of person, and out of focus were selected for subjective evaluation items and evaluated by image processing method. By applying objective and subjective assessment items, the results were very accurate, with the results obtained by the developed program and the results of the actual visual inspection. but since the currently developed program can be evalua ted only after facial recognition of the person, future research will need to develop a program that can evaluate all kinds of portraits.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2008.11a
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• pp.69-72
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• 2008

본 논문에서는 PSNR 이 다른 어떤 척도보다도 화질의 평가에 있어서 중요하다는 전제하에 비쥬얼리듬 (VR) 정보를 이용하여 원본영상이 가용하지 않은 일반 시청자들의 STB 재생영상으로부터 PSNR 을 추정하는 방법을 제안하였다. VR 로부터 추정한 PSNR 값이 매 프레임 별로 2 차원 재생영상으로부터 구한 PSNR 과 같지는 않으나 시청자들이 평균적으로 어느 정도의 화질로 시청하고 있는지 비교적 정확하게 모니터링이 가능하다. 제안된 방법은 감소기준법(RR) 영상품질 측정방법으로 사용될 수 있다. STB 은 단순히 재생영상으로부터 VR 정보만 추출해서 서버로 전송하는 역할만 수행하면 되고, 나머지 연산은 품질관리 서버에서 수행하므로 자원이 부족한 STB 의 부담을 경감하면서도 효율적으로 품질을 모니터링할 수 있는 장점이 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.16-19
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• 2013

화이트 밸런스를 유지해야 하는 이유는 입력 이미지의 컬러 밸런스와 동질의 화질 유지를 위하거나, 혹은 이미지를 개선할 때 화질 균일 성을 유지하기 위함이다. 그러나 기존 컬러 개선 방식들은 화이트 밸런스 보존에 관계없이 컬러 개선이 이루어지기 때문에 컬러 개선 전과 후의 화이트 밸런스가 다르게 나타난다. 이 논문에서는 색 순응 변환을 이용하여 화이트 밸런스를 보존하면서 자연스러운 컬러 이미지 개선 및 컬러 측정 알고리즘을 제안한다. 그 결과는 제안된 알고리즘은 Color Naturalness Index 와 Color Colorful Index 라고 풀리는 객관적 방법뿐만 아니라 주관적인 방법 에서도 개선됨을 확인하였다. 알고리즘의 복잡도는 낮으므로 현실 어플리케이션에서도 유용하게 이용될 것이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.109-112
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• 2003

본 논문은 비트 플레인의 위치에 따라 정보 삽입량에 대한 주관적이고 고정적인 임계치가 아니라 비트 플레인의 가중치를 고려하여 각 영상의 비트 플레인별 적응적인 임계값에 따라 최대 정보량을 삽입하고 추출하는 알고리즘을 연구하였다. 다양한 이미지를 대강으로 고정 임계값을 적용하는 기존의 방법과 영상의 특징에 따라 비트 플레인별 임계값이 적응적으로 산출되는 제안한 방법에 대해서 최대용량을 측정하고, 같은 양의 정보를 삽입한 후 화질을 비교 분석하였다. 그 결과 기존의 방법보다 용량면이나 화질면에서 나은 결과를 얻을 수 있었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.155-157
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• 2020

본 논문은 딥러닝 기반의 중첩 블록 단위 이미지 압축 방법에 대하여 제안한다. 이미지를 블록 단위로 나누어 압축을 진행하며, 그 과정에서 생길 수 있는 블록화 현상을 제거하기 위해 블록의 주변부를 압축에 이용한다. 이로 인한 추가적인 부하를 제거하기 위해 복호화에 필요한 부하 영역을 제거한 뒤, 복호화기에서 특징맵들을 병합하여, 제거한 영역에 대해 주변 블록의 정보를 사용하여 복호화를 진행한다. 압축을 진행하고자 하는 이미지의 크기에 따라 급격하게 증가하는 요구 메모리를 이미지의 크기에 상관 없이 고정된 작은 메모리로 이미지 압축을 진행할 수 있다는 장점이 있다. 실험 결과로써 4K 이미지를 통해서 복원된 화질과 메모리의 사용량을 측정한 결과, 동일한 화질을 유지함과 동시에, 기존 방법대비 약 500배 적은 메모리 사용량을 보인다.

• The Journal of Society for e-Business Studies
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• v.15 no.3
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• pp.63-83
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• 2010

IPTV(Internet Protocol Television) is an innovation technology to lead the new media age. Internet protocol television (IPTV) is a next generation television converged with the Internet which are delivered portal services such as information search, games, movies, home shopping and banking. Generally, service quality affects to adopt or use these technologies. Quality of experience (QoE) is more issue to be considered than service quality because of the technological restriction and limitation that IPTV is accessed by the Internet. The QoE is defined as the cognitive and experienced quality measured with users through an experiment and is conceptually related to service quality. The objective of this paper is to suggest a methodology to measure the QoE of IPTV using a user testing. We find significant factors affecting QoE of IPTV through an exploratory study and measure QoE scores. We found the nine factors of graphics, picture, accuracy, access method, quality of contents, usability, security, and performance important for QoE. The QoE scores of picture, graphics, and quality of contents gained over the average score, but the overall score for IPTV service providers was not high and the QoE needs to be improved.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.49 no.4
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• pp.32-39
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• 2012

This paper develops a robust image enhancement method by adjusting image signal energy according to the direction and the variation of image signal in DCT domain. To accomplish this, we measure the gradient of image signal directly in DCT domain and then adjust frequency components involved in sharpness, local contrast and global contrast using the direction and the magnitude of the measured gradient The experiment showed that the proposed method produces the best quality of an image without causing blocking, ringing artifacts and boosting noise.

• Journal of the Korean Society of Radiology
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• v.8 no.4
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• pp.147-153
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• 2014

We tried to assessment about characteristics of image through quantitative evaluation method and qualitative evaluation method in Full Field Digital Mammography. It satisfied an approval standard of ten score regardless of compression ratio measuring detection score after compressing and appling an algorithm of JPEG2000 orJPEG compression targeting ACR accreditation phantom. Also, it was apparent that when we selected and compressed the image of real fine lesion and measured a change of diagnosis ability magnifing over 50 percent after compressing over 20:1 ratio, it had a strong influence on diagnosis ability. We realized that the difference between the original image according to compression ratio measuring a quantitative evaluation which is PSNR,RMSE,MAE and SSIM was relatively allowable.

• Journal of Broadcast Engineering
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• v.21 no.2
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• pp.157-168
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• 2016

In image processing and computer vision fields, mean squared error (MSE) has popularly been used as an objective metric in image quality optimization problems due to its desirable mathematical properties such as metricability, differentiability and convexity. However, as known that MSE is not highly correlated with perceived visual quality, much effort has been made to develop new image quality assessment (IQA) metrics having both the desirable mathematical properties aforementioned and high prediction performances for subjective visual quality scores. Although recent IQA metrics having the desirable mathematical properties have shown to give some promising results in prediction performance for visual quality scores, they also have high computation complexities. In order to alleviate this problem, we propose a new fast IQA metric using a simple Laplace operator. Since the Laplace operator used in our IQA metric can not only effectively mimic operations of receptive fields in retina for luminance stimulus but also be simply computed, our IQA metric can yield both very fast processing speed and high prediction performance. In order to verify the effectiveness of the proposed IQA metric, our method is compared to some state-of-the-art IQA metrics. The experimental results showed that the proposed IQA metric has the fastest running speed compared the IQA methods except MSE under comparison. Moreover, our IQA metric achieves the best prediction performance for subjective image quality scores among the state-of-the-art IQA metrics under test.