• 한국정보처리학회논문지
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• 제7권11호
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• pp.3592-3602
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• 2000

영상 처리는 크게 영상에 내재된 특성값을 얻어내는 영상분석과, 동일한 성질의 영상을 분류하는 영상분류의 두단계로 이루어진다. 본 논문에서는 텍스쳐에 내재된 일반적인 속성인 거침과 부드러움의 특성 추출을 통해서 영상에 포함된 다양한 텍스쳐를 자동적으로 인식하고 분류하는 방법을 제안한다. 특성추출은 텍스쳐 영상이 지닌 그레이 레벨의 공간적인 의존성을 이용한 통계적 분석에 기반한 것으로 모멘트와 동차성의 조합을 통해서 일반적인 텍스쳐의 속성을 검출하기 때문에 텍스쳐의 구조형태에 크게 영향을 받지 않는 이점을 가지고 있다. 거친 텍스쳐일수록 강하게 반응하는 모멘트와 부드러운 텍스쳐일수록 강하게 반응하는 동차성의 차를 이용하기 때문에 보다 뚜렷한 텍스쳐 분할이 가능하다. 제안한 시스템의 성능 평가를 위해서 다양한 텍스쳐 영상에 제안한 방법을 적용하고, 성공적인 결과를 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.5058-5072
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• 2015

Quaternions have been commonly employed in color image processing, but when the existing pure quaternion representation for color images is used in perceptual hashing, it would degrade the robustness performance since it is sensitive to image manipulations. To improve the robustness in color image perceptual hashing, in this paper a full quaternion representation for color images is proposed by introducing the local image luminance variances. Based on this new representation, a novel Full Quaternion Discrete Cosine Transform (FQDCT)-based hashing is proposed, in which the Quaternion Discrete Cosine Transform (QDCT) is applied to the pseudo-randomly selected regions of the novel full quaternion image to construct two feature matrices. A new hash value in binary is generated from these two matrices. Our experimental results have validated the robustness improvement brought by the proposed full quaternion representation and demonstrated that better performance can be achieved in the proposed FQDCT-based hashing than that in other notable quaternion-based hashing schemes in terms of robustness and discriminability.

• Journal of the Korean Wood Science and Technology
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• 제33권5호통권133호
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• pp.21-28
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• 2005

For the proper conservation of wooden cultural properties, non-destructive evaluation (NDE) method, which can be used to quantitatively evaluate the internal state of wood members, are needed. In this study, an ultrasonic CT system composed of portable devices was attempted, and the capacity of this system was verified by reconstructing the CT images for two phantoms and two artificially defected specimens. Results from this study showed that the sizes of detected defects were enlarged and the shapes were distorted on the CT images. Also, the positions were shifted somewhat toward the surface of specimen, which is regarded due to the anisotropic property of wood. Compared to the filtered back-projection method, SIRT (simultaneous iterative reconstruction technique) method was determined to be more efficient as the algorithm of image reconstruction for wood. A new ultrasonic CT system is thought to be used as a NDE method for wood. However wood characteristics and wave diffraction within wood made it difficult to accurately evaluate the size, shape and position of defects. To improve the quality of CT image of wood, more research including the relationship between wood and ultrasound is needed, and wood properties should be taken into consideration on the image reconstruction algorithm.

• Journal of the Korean Wood Science and Technology
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• 제33권5호통권133호
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• pp.29-37
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• 2005

A previous study verified that the SIRT (simultaneous iterative reconstruction technique) method is more efficient than the back-projection method as a CT algorithm for wood. However, it was expected that the determination of the initial model function of the SIRT method would influence the quality of CT image. Therefore, in this study, we intended to develop a technique that could be used to determine an adequate initial model function. For this purpose, we proposed several techniques, and for each technique we examined the effects of the initial model function on the average errors and the CT image at each iteration. Through this study, it was shown that the average error was decreased and the image quality was improved using the proposed techniques. This tendency was most pronounced when the back-projection method was used to determine the initial model function. From the results of this study, we drew the following conclusions: 1) The initial model function of the SIRT method should be determined with careful attention, and 2) the back-projection method efficiently determines the initial model function of the SIRT method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.176-180
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• 2001

In this paper, we have studies the images have been reconstructed by using combination of images which has been acquired by the variation of operating frequency. When inner images has been reconstructed, inner image has been superposition by surface state effect. In this case, image enhancement the phase object and enhance the contrast of inner image. In the result of the specimen for the round defect with 2mm diameter, for the types of the depth are 1.5mm, 2mm, 2.5mm, and 3mm, it has been show that the shape of defect has better than before this processing and phase contrast grow large twice. And we have constructed the acoustic microscope by using quadrature detector that is able simultaneously to acquired the amplitude and phase of the reflected signal. Father more we have studied the reconstruction method of the amplitude and phase images and the enhancement method of the defect images' contrast.

• 비파괴검사학회지
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• 제30권2호
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• pp.98-103
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• 2010

본 논문은 공업플랜트의 이상 발생을 작업자의 위험 부담없이 확인 및 유지보수가 용이하게 하기 위한 CCD와 열화상 이미지 처리기법에 관한 것이다. 넓은 영역의 상태 확인을 위해 카메라 대수에 상관없이 하나의 이미지로 확인을 위한 panorama 알고리즘 기법을 개발하였다. 열화상의 영상처리를 용이하도록 영상간 이미지 융합기술을 개발하였다. 실시간으로 빠른 이미지 처리를 위하여 최초 이미지를 융합하고, 이 때의 매칭 데이타를 저장하여 이후로 영상 융합시 매칭포인트와 매칭위치 검색은 생략을 하여 시간을 절약할 수 있었다.

• 한국컴퓨터정보학회논문지
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• 제24권1호
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• pp.85-92
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• 2019

In this paper, we propose a efficient feature point extraction method that can solve the problem of performance degradation by introducing a preprocessing process when extracting feature points by utilizing the characteristics of 360-degree realistic media. 360-degree realistic media is composed of images produced by two or more cameras and this image combining process is accomplished by extracting feature points at the edges of each image and combining them into one image if they cover the same area. In this production process, however, the stitching process where images are combined into one piece can lead to the distortion of non-seamlessness. Since the realistic media of 4K-class image has higher resolution than that of a general image, the feature point extraction and matching process takes much more time than general media cases.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.6611-6617
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• 2015

본 연구는 수작업으로 제작된 metal coping과 CAD/CAM(Computer Aided Design/Computer Aided Manufacturing)으로 제작된 지르코니아 coping을 제작하여 변연과 내면 적합도를 비교 분석하고자 하였다. 모형은 우레탄 모형재를 사용하여 knife, chamfer변연 두 종류의 지대치를 제작하였다. 수작업과 CAD/CAM으로 제작된 보철물의 변연 적합도를 실리콘 리플리카 테크닉방법을 사용하여 측정하였다. 적합도 측정은 현미경의 CCD카메라로 캡쳐하였다. 이때 지대치와 보철물의 거리는 이미지분석 소프트웨어에서 거리 조정이 된 상태에서 실시하였다. 측정부위는 marginal opening을 MO, marginal gap을 MG, internal gap을 IG, Axial gap을 AG, occlusal gap을 OG로 하였다. 제작법과 변연 형태에 따른 비교분석을 위해 이원배치분산분석을 실시하였으며 서로 다른 평균값들의 비교 분석을 위해서 일원배치분산분석과 Scheffe's 사후 검정을 실시하였다. 그 결과 CAD/CAM의 OG와 knife 변연의 MO을 제외하고는 < $120{\mu}m$ 적합도를 나타냈다. CAD/CAM으로 제작된 coping은 chamfer 변연 MO에서 높은 적합도를 보였으나 MG에서는 knife변연이 chamfer변연 보다 더 좋은 적합도를 보였다. AG의 내면 적합도는 가장 좋은 값을 나타내었다(< $38{\mu}m$).

• Journal of the Korean Wood Science and Technology
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• 제38권6호
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• pp.498-506
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• 2010

국산 침엽수재를 고부가가치의 구조부재로 활용하기 위해서는 국내 기준에 적합한 등급구분 체계가 갖춰져야 한다. 김 등(2009a, b)의 연구에서는 목재의 생산 및 유통규모가 작은 국내 현실에서 제재목 등급구분의 자동화 및 기계화를 목적으로 화상처리시스템을 개발하였다. 본 연구에서는 이전 연구에서 개발한 화상처리시스템의 핵심 기술 중 하나인 화상입력시스템의 성능을 향상시키기 위하여 최적 화상병합 조건을 구명하고자 하였다. 연구 결과 국산 낙엽송 $180{\time}120$ mm 부재의 화상을 병합하는 데 있어서 획득된 화상의 green채널 정보를 병합 에 이용하는 것이 가장 높은 병합정확성을 얻을 수 있었다. 입력된 화상의 전처리 과정으로 Y-derivative Sharr's kernel 필터를 적용함으로써 화상병합 성능을 향상시킬 수 있었으나, 카메라 보정에 의한 효과는 미미 하였다. 또한 화상병합을 위한 최적 템플릿 크기는 폭 30 pixel ${\time}$ 높이 150 pixel로 확인되었다. 이상의 조건을 적용하였을 때, 병합된 화상의 길이오차는 평균 3.1 mm, 연산시간은 평균 9.7초로 나타났다.

• 동아시아식생활학회지
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• 제23권2호
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• pp.141-152
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• 2013

This study investigated the effects of image on the preference and intake frequency of 19 vegetables. A total of 359 usable surveys were collected using a convenient sampling method. The subjects included females (51.8%), university students (50.7%), home residents (66.9%) and subject's spending 20,000~40,000 won on meals/week (41.5%) and eat out 2~3 times/week (29.5%). The intake frequency of vegetables was 2~3 times per month. The healthy image of all vegetables was good overall and the average preference was 3.78 (out of 5 on the Likert). Tomatoes had the healthiest image, onions the highest preference, and Korean cabbage the highest intake frequency. For males, the vegetable with the healthiest image was sesame leaf, while the healthiest foods for females were broccoli and tomatoes. Elementary students had a healthier image of cucumber, bean sprouts, radish, sesame leaf, lettuce, radish leaf, and cabbage than university students and adults. Home residents had a healthier image of cabbage and burdock than other types of residents. Subject that st over 20,000 won per week on meals had a higher image of most vegetables. In terms of preference, males liked Korean cabbage, green pumpkin, balloon flower roots, radish leaf, and lotus root, but female liked tomatoes. In addition, elementary students, home residents, and subjects who eat out less often tended to prefer vegetables. In terms of intake, there was a high frequency of intake for all vegetables in adults. Home residents specifically had a higher intake of cucumber, carrot, bean sprouts, spinach, green pumpkin, balloon flower roots, lettuce, radish leaf, broccoli, burdock, lotus root, and tomato. Overall, the healthy image of vegetables had a positive influence on their preference and intake frequency. Therefore, to encourage the intake of vegetables, direct or indirect variables should be examined.