• 반도체디스플레이기술학회지
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• 제9권4호
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• pp.57-61
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• 2010

The wavelet transform was adopted as the transform for JPEG2000. However, wavelet has weakness about smoothness along the contours and limited directional information. So we use to other transform, called contourlet transform in compression. Objective quality assessment methods currently used Peak signal to noise Ratio(PSNR). But that is not very well matched to perceived visual quality. So new image quality assessment is required. In this paper, we propose a new method for image compression based on the contourlet transform, which has been recently introduced. In addition we evaluated compression image quality using PSNR and SSIM. Finally contourlet transform has a good result about images with smooth contours and SSIM is good method for image evaluation compared to PSNR.

• Journal of Information Processing Systems
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• 제16권6호
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• pp.1479-1494
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• 2020

As an important part of image processing, image demosaicking has been widely researched. It is especially necessary to propose an efficient interpolation algorithm with good visual quality and performance. To improve the limitations of residual interpolation (RI), based on RI algorithm, minimalized-Laplacian RI (MLRI), and iterative RI (IRI), this paper focuses on adaptive RI (ARI) and proposes an improved ARI (IARI) algorithm which obtains more distinct R, G, and B colors in the images. The proposed scheme fully considers the brightness information and edge information of the image. Since the ARI algorithm is not completely adaptive, IARI algorithm executes ARI algorithm twice on R and B components according to the directional difference, which surely achieves an adaptive algorithm for all color components. Experimental results show that the improved method has better performance than other four existing methods both in subjective assessment and objective assessment, especially in the complex edge area and color brightness recovery.

• ETRI Journal
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• 제44권1호
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• pp.94-104
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• 2022

Because of its convenience and compatibility with various image processing techniques, digital image representation of holograms is generally used in digital holography, and thus, quality assessment of digital holograms is an essential issue. This study proposes a new objective quality metric for digital phase hologram image processing. The proposed metric is based on a newly defined phase distortion created by taking the 2π periodicity of phase information into account. The experimental results show that the proposed metric correlates with reconstruction image quality better than the existing metric under random distortions and also works well with JPEG 2000 compression. It is expected to be broadly used in phase image processing and compression applications including phase holograms.

• Journal of Welding and Joining
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• 제27권2호
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• pp.51-56
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• 2009

Film based radiography imaging technique has been applied to the non-destructive test in medical, aircraft, and power industries contributing to the development of the industries. However, the complex process for imaging and analysis has increasingly demanded the reformation of the radiography test. A digital radiography imaging technologies has been com out from the demand. This study was mainly focused on the assessment on the accuracy for the each image from digital radiography test and film radiography test was proven to crate a better image in sensitivity than film radiography test. In the IQI(Image quality indicator) transmission test, one or two more line can be seen in digital image than in film image. When applying to the boiler tube weld, film image is detectable to the 1.0mm depth flaw; and digital image to the 0.5mm depth flaw. As a result of this study, digital radiography technology is determined to enhance the image quality, compared to film radiography technologies

• 한국측량학회:학술대회논문집
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• 한국측량학회 2004년도 춘계학술발표회논문집
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• pp.259-262
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• 2004

There is the case to make the image map by using color aerial photo, DEM gives the accuracy of the Ortho image. Therefore We evaluate the accuracy by digital photogrammetric system after generating the DEM of Color Aerial Image.

• 한국콘텐츠학회논문지
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• 제16권8호
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• pp.592-600
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• 2016

AAPM CT 성능 평가용 표준 팬텀을 이용한 특수의료장비 품질관리 검사 시, 평가자의 주관적인 평가로 인한 오류를 최소화 하고자 전산화된 평가 프로그램을 이용하여 유용성을 평가하고자 한다. 평가 팬텀으로 AAPM CT Performance Phantom을 사용하였고, 기본 촬영 조건은 품질관리검사와 동일하며, 평가프로그램으로 IMAGE J를 사용하였다. 정량적인 평가로 CT 감약계수와 노이즈측정, 균일도측정, 슬라이스 두께 측정, 대조도 분해능 측정, 공간 분해능 측정의 팬텀 영상을 평가프로그램을 이용하여 영상처리를 한 후 자동추출 된 결과로 평가 하였으며, CT 감약계수, 노이즈, 균일도 측정은 영상처리를 한 영상의 표준편차가 작아 더 균일하다고 평가하였고, 슬라이스 두께 측정은 팬텀영상의 측정값과의 비율 차로 인해 평가에 어려움이 있었다. 대조도 분해능은 원통형의 지름을 6회 측정하여 지름의 평균값과 표준편차를 구해 원의 형태를 평가하였으며, 공간 분해능은 합격기준을 포함하는 원의 그룹을 자동 추출한 결과 원의 개수를 모두 추출한 결과로 나타났다. 정성적인 평가로 원본영상과 영상 처리한 영상을 육안적으로 비교 평가 하였는데 영상처리 된 영상이 우수한 결과를 나타내었다. 위의 결과 등을 바탕으로 평가자의 주관적인 판단의 오류를 최소화하기 위해서는 정량적인 평가와 정성적인 평가가 함께 이루어져야 하고 전산화된 평가프로그램을 활용한다면 보다 더 효율적인 평가가 이루어 질 것이라고 사료된다.

• Journal of Information Processing Systems
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• 제12권4호
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• pp.631-643
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• 2016

Due to the block-based discrete cosine transform (BDCT), JPEG compressed images usually exhibit blocking artifacts. When the bit rates are very low, blocking artifacts will seriously affect the image's visual quality. A bilateral filter has the features for edge-preserving when it smooths images, so we propose an adaptive-weighted bilateral filter based on the features. In this paper, an image-deblocking scheme using this kind of adaptive-weighted bilateral filter is proposed to remove and reduce blocking artifacts. Two parameters of the proposed adaptive-weighted bilateral filter are adaptive-weighted so that it can avoid over-blurring unsmooth regions while eliminating blocking artifacts in smooth regions. This is achieved in two aspects: by using local entropy to control the level of filtering of each single pixel point within the image, and by using an improved blind image quality assessment (BIQA) to control the strength of filtering different images whose blocking artifacts are different. It is proved by our experimental results that our proposed image-deblocking scheme provides good performance on eliminating blocking artifacts and can avoid the over-blurring of unsmooth regions.

• 환경영향평가
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• 제8권1호
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• pp.61-70
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• 1999

The purpose of this study is to understand an appreciation and a perceptive structure of "keijeok" image by Semantic Differential Technique and Factor Analysis. The data used in this study was obtained by the questionnaire survey carried out in Pusan metropolitan city. 15 adjective pairs in the survey were evaluated by the Semantic Differential scales graded 7 ranges from 1(very good) to 7(very bad). A total of 452 samples were collected by the survey and analyzed for this study. The results are as follows; First, 15 variables comprehended to "keijeok" image were estimated as a positive conception(LT 4.0). What's more, residents may perceive "keijeok" image as intangible and aesthetic aspect such as "fresh", "pleasant", "clean". Second, the result of factor analysis shows that factor I which express the major conceptual meaning of "keijeok" image tends to have intangible or aesthetic adjective pairs rather than concrete, whereas factor II which has the weaker meaning compared with factor I may represent a functional aspect of "keijeok" image. It can explain that the perceptive structure of "keijeok" image may be largely influenced by subjective sense, then added or concreted with objective conception or environmental situation. The results can be considered as an important matter which should be reflected at the stage of environmental planning for people's amiable and desirable place.

• 한국실내디자인학회논문집
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• 제13권5호
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• pp.190-197
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• 2004

A kindergarten requires an approach to meet the nature and sense of children who is main users. This study selected 33 private kindergartens which were located within a housing site development zone in Gwangju since the 1990's, had single use, and was constructed in the last five years. Also the image assessment according to types of color scheme was made. Then the factors which affected preference by type were analyzed and the basic of color scheme in a kindergarten classroom was provided. The following results were obtained. First, types of color scheme in a classroom included identity 12.1%, similarity 51.5%, and novelty 36.4% in harmony, but no contrast and achromatic color, Secondly, the assessment of preference according to each type was mostly positive. The highest preference was found in similarity harmony of warm color(e.g. YR, Y) and bright, clear, nice, and strong images were high in assessment. The lowest preference was found in identity harmony of cold color(e.g. GY). This color system had no clear image assessment, except manly or strong. In particular, warm color showed higher preference than cold color in similarity, novelty, and identity harmony. Thirdly, the factors affecting the preference of color scheme in a classroom most were ‘stable - unstable’, ‘clean - dirty’, ‘bright - dark’, ‘nice - not nice’, and ‘vital - dull’.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권7호
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• pp.2938-2956
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• 2020

Objective image quality assessment (IQA) models have been developed by effective features to imitate the characteristics of human visual system (HVS). Actually, HVS is extremely sensitive to color degradation and complex texture changes. In this paper, we firstly reveal that many existing full reference image quality assessment (FR-IQA) methods can hardly measure the image quality with contrast and masking texture changes. To solve this problem, considering texture masking effect, we proposed a novel FR-IQA method, called Texture and Color Quality Index (TCQI). The proposed method considers both in the masking effect texture and color visual perceptual threshold, which adopts three kinds of features to reflect masking texture, color difference and structural information. Furthermore, random forest (RF) is used to address the drawbacks of existing pooling technologies. Compared with other traditional learning-based tools (support vector regression and neural network), RF can achieve the better prediction performance. Experiments conducted on five large-scale databases demonstrate that our approach is highly consistent with subjective perception, outperforms twelve the state-of-the-art IQA models in terms of prediction accuracy and keeps a moderate computational complexity. The cross database validation also validates our approach achieves the ability to maintain high robustness.