• Imaging Science in Dentistry
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• 제45권2호
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• pp.81-87
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• 2015

Purpose: Contrast, sharpness, enhancement, and density can be changed in digital systems. The important question is to what extent the changes in these variables affect the accuracy of caries detection. Materials and Methods: Forty eight extracted human posterior teeth with healthy or proximal caries surfaces were imaged using a photostimulable phosphor (PSP) sensor. All original images were processed using a six-step method: (1) applying "Sharpening 2" and "Noise Reduction" processing options to the original images; (2) applying the "Magnification 1:3" option to the image obtained in the first step; (3) enhancing the original images by using the "Diagonal/"option; (4) reviewing the changes brought about by the third step of image processing and then, applying "Magnification 1:3"; (5) applying "Sharpening UM" to the original images; and (6) analyzing the changes brought about by the fifth step of image processing, and finally, applying "Magnification 1:3." Three observers evaluated the images. The tooth sections were evaluated histologically as the gold standard. The diagnostic accuracy of the observers was compared using a chi-squared test. Results: The accuracy levels irrespective of the image processing method ranged from weak (18.8%) to intermediate (54.2%), but the highest accuracy was achieved at the sixth image processing step. The overall diagnostic accuracy level showed a statistically significant difference (p=0.0001). Conclusion: This study shows that the application of "Sharpening UM" along with the "Magnification 1:3" processing option improved the diagnostic accuracy and the observer agreement more effectively than the other processing procedures.

• 한국콘텐츠학회논문지
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• 제14권11호
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• pp.1-6
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• 2014

감성 인식은 기계가 작업을 자동적으로 판단하여 인간의 감성을 인식하도록 하는 것이다. 인간의 감성은 매우 주관적이므로 객관적인 측정이 불가능하다. 따라서 감성 인식의 목표는 가급적 많은 사람들이 공감하는 척도를 만드는 것이다. 영상에서의 감성 인식은 영상의 여러 가지 특징을 감성과 매칭하는 방법으로 구현된다. 본 논문에서는 고바야시의 영상 척도를 참고하여 의류 영상에서 색상 특징을 이용한 감성 인식 시스템을 제안한다. 제안 시스템은 영상 척도의 색상 정보를 데이터화하고, 입력 의류 영상에서 추출한 색상을 저장된 색상 데이터와 비교하여 가장 유사한 색상을 찾고, 이 색상과 연관된 감성을 출력한다. 제안된 시스템은 한 의류 영상에서 최대 3개까지 감성을 찾을 수 있다. 제안한 시스템의 성능을 평가하기 위하여 70명의 관찰자가 검사하였다. 그 결과에 따르면 제안한 시스템이 인식한 감성과 관찰자의 감성이 매우 유사하였다.

• 인지과학
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• 제14권4호
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• pp.9-19
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• 2003

Bonneh, Cooperman 과 sagi (2001)[1] 는 역치이상의 강도를 갖는 정지자극이 운동자극과 섞여서 제시될 때 정지자극이 의식에서 간헐적으로 소멸함을 보고하면서 이 현상을 MIB (motion-induced-blindness)라고 명명하였다. 본 연구에서는 흰색 점으로 구성된 회전하는 원통체와 함께 제시되는 녹색 정지 점들을 오른쪽 눈에 적색 필터를 착용하고 관찰할 경우에 녹색 정지 점들이 의식에서 간헐적으로 소멸함을 보여주었다. 본 연구에서 관찰되는 MIB 현상은 원통체가 회전할 때에 그리고 한 쪽 눈에 적색 필터를 착용할 때에만 나타난다. 또한 녹색 점의 명도대비와 원통체를 구성하는 흰색 점의 명도대비가 감소할수록 녹색 정지점이 의식에서 소멸하는 시간이 감소하였으며, 정지자극과 운동자극을 구성하는 점의 수가 감소할수록 정지자극이 의식에서 소멸하는 시간이 감소하였다. 흥미롭게도 정지자극과 운동자극의 상대적인 깊이가 정지자극이 소멸하는 시간에 영향을 미쳤다. 이러한 실험결과는 본 연구에서 보고하는 MIB 현상이 Bonneh 등이 보고한 MIB 현상과 구별되며, 양안경쟁으로는 이 현상이 설명할 수 없고, 시각 정보처리에서 후기단계의 정보처리가 이 현상에 관여함을 시사한다.

• Radiation Oncology Journal
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• 제32권1호
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• pp.43-47
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• 2014

Purpose: The degree of radiation-induced lung fibrosis (RILF) can be measured quantitatively by fibrosis volume (VF) on chest computed tomography (CT) scan. The purpose of this study was to investigate the interobserver and intraobserver variability in CT-based measurement of VF. Materials and Methods: We selected 10 non-small cell lung cancer patients developed with RILF after postoperative radiation therapy (PORT) and delineated VF on the follow-up chest CT scanned at more than 6 months after radiotherapy. Three radiation oncologists independently delineated VF to investigate the interobserver variability. Three times of delineation of VF was performed by two radiation oncologists for the analysis of intraobserver variability. We analysed the concordance index (CI) and inter/intra-class correlation coefficient (ICC). Results: The median CI was 0.61 (range, 0.44 to 0.68) for interobserver variability and the median CIs for intraobserver variability were 0.69 (range, 0.65 to 0.79) and 0.61(range, 0.55 to 0.65) by two observers. The ICC for interobserver variability was 0.974 (p < 0.001) and ICCs for intraobserver variability were 0.996 (p < 0.001) and 0.991 (p < 0.001), respectively. Conclusion: CT-based measurement of VF with patients who received PORT was a highly consistent and reproducible quantitative method between and within observers.

• Imaging Science in Dentistry
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• 제45권1호
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• pp.23-29
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• 2015

Purpose: This study aimed to assess the reliability of measurements performed on three-dimensional (3D) virtual models of maxillary defects obtained using cone-beam computed tomography (CBCT) and 3D optical scanning. Materials and Methods: Mechanical cavities simulating maxillary defects were prepared on the hard palate of nine cadavers. Images were obtained using a CBCT unit at three different fields-of-views (FOVs) and voxel sizes: 1) $60{\times}60mm$ FOV, $0.125mm^3$ ($FOV_{60}$); 2) $80{\times}80mm$ FOV, $0.160mm^3$ ($FOV_{80}$); and 3) $100{\times}100mm$ FOV, $0.250mm^3$ ($FOV_{100}$). Superimposition of the images was performed using software called VRMesh Design. Automated volume measurements were conducted, and differences between surfaces were demonstrated. Silicon impressions obtained from the defects were also scanned with a 3D optical scanner. Virtual models obtained using VRMesh Design were compared with impressions obtained by scanning silicon models. Gold standard volumes of the impression models were then compared with CBCT and 3D scanner measurements. Further, the general linear model was used, and the significance was set to p=0.05. Results: A comparison of the results obtained by the observers and methods revealed the p values to be smaller than 0.05, suggesting that the measurement variations were caused by both methods and observers along with the different cadaver specimens used. Further, the 3D scanner measurements were closer to the gold standard measurements when compared to the CBCT measurements. Conclusion: In the assessment of artificially created maxillary defects, the 3D scanner measurements were more accurate than the CBCT measurements.

• 디지털융복합연구
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• 제13권4호
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• pp.357-368
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• 2015

사람들은 항상 사건들과 접하고 그것을 지각하며 산다. 우리는 이러한 광학 흐름의 결과로 볼 수 있는 사건들을 어렵지 않게 인지한다. 문제는 사람들이 어떻게 이러한 사건들을 인지하며 광학 흐름 중 어떠한 정보가 우리로 하여금 이러한 사건들을 인지하게 만드는 지이다. 운동이론학자들은 인간은 이러한 사건들을 생산함과 동시에 지각하기 때문에 말소리 지각이나 생물학적 운동과 같은 사건들을 지각하는 것에 특별한 감각을 가지고 있다고 주장해왔다. 하지만, 직접지각 접근법 연구자들은 말소리 지각이나 생물학적 운동은 어떠한 다른 사건들을 지각하는 것과 다르지 않다고 제안했다. 이 논문의 목적은 사건지각에 관한 운동이론과 직접지각 접근법의 관점에 대해 설명하고 운동이론을 비판함으로써 이 두 이론을 비교하는 것이다. 점차 발전하고 있는 로봇공학과의 융합에 있어서 이러한 인간의 기본적인 사건 지각 능력을 먼저 이해하는 것이 중요하다.

• 한국실내디자인학회논문집
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• 제24권2호
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• pp.32-41
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• 2015

We live in the era of unlimited design competition. As the importance of design is increasing in all areas including marketing, each country does its best effort on design development. However, the preparation on protecting interior design rights by intellectual property laws(IPLs) has not been enough even though they occupy an important place in the design field. It is not quite easy to make a judgement on the similarity between two images having a single common factor because the factors which are composed of interior design have complicated interactive relations between them. From the IPLs point of view, designs with the similar overall appearance are decided to be similar. Objective evaluation criteria not only for designers but also for design examiners and judges are required in order to protect interior design by the IPLs. The objective of this study is the analysis of the possibility that a computer algorithm method can be useful to decide the similarity of interior design images. According to this study, it is realized that the Img2 which is one of content-based image retrieval computer programs can be utilized to measure the degree of the similarity. The simulation results of three descriptors(CEDD, FCTH, JCD) in the Img2 showed the high degree of similar patterns compared with the results of perceptual judgment by observers. In particular, it was verified that the Img2 has high availability on interior design images with a high score of similarity below 60 which are perceptually judged by observers.

• 인지과학
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• 제18권3호
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• pp.285-303
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• 2007

특정 위치에 주의를 주게 되면, 그 위치에 있는 사물을 시각적으로 처리할 때에 시간 해상도가 저하되며, 이러한 저하는 큰세포(parvocellular)와 작은 세포(magnocellular)의 상호 억제적 연결에 기인하는 것이라고 주장이 제기되었다. 이와는 다르게, 시각 주의가 같은 위치에 연속적으로 제시되는 자극들간의 시간적 겹침을 유발하기 때문에, 주의에 의한 시간 해상도 저하가 관찰되었을 가능성이 있다. 본 연구에서는, 이 가설을 검증하기 위해, 배경 대비 자기의 극성이 다른 두개의 자극들을 사용해 자극 제시 순서를 판단하는 과제를 실시했다. 밝기 극성이 다른 자극들은 초기 시각 처리과정에서 서로 다른 경로를 통해 처리되기 때문에, 주의가 주어진다고 하더라도 시간적 중복이 촉진되지 않을 것이다. 실험 결과, 실험 참가자들은 시각 단서가 주어지지 않은 위치에서보다 주어진 위치에 나타난 자극들의 제시순서를 더 정확하게 판단했다. 반면, 같은 밝기 극성을 가진 두 개의 자극에 대한 제시 순서를 판단해야 했을 때에는, 시각 단서가 주어진 위치보다 주어지지 않은 위치에 나타난 자극들에 대해서 더 정확하게 제시순서를 보고했다. 이러한 결과는, 시각적 주의가 자극 신호의 시간적 중복을 유도함을 통해 시각적 시간해상도에 영향을 미친다는 것을 의미한다.

• Imaging Science in Dentistry
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• 제34권4호
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• pp.185-190
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• 2004

Purpose: To compare the diagnostic accuracy for the detection of root fractures in CMOS-based digital periapical images with conventional film-based periapical images. Materials and Methods: Sixty extracted single-root human teeth with closed apices were prepared endodontically and divided into two groups; artificially induced vertical root fracture group and control group. All radiographs were obtained using the paralleling technique. The radiographs were examined by 4 observers three times within a 4 week interval. Receiver operating characteristic (ROC) analysis was carried out using data obtained from four observers. Intra- and inter-examiner agreements were computed using kappa analysis. Results: The area under the ROC curve (Az) was used as an indicator of the diagnostic accuracy of the imaging system. Az values were as follows: direct-digital images; 0.93, film-based images; 0.92, and inverted digital images; 0.91. There was no significant difference between imaging modalities (P<0.05). The kappa value of inter-observer agreement was 0.42 (range: 0.28-0.60) and intra-observer agreement was 0.57 (range: 0.44-0.75). Conclusion : There is no statistical difference in diagnostic accuracy for the detection of vertical root fractures between digital periapical images and conventional periapical images. The results indicate that the CMOS sensor is a good image detector for the evaluation of vertical root fractures.

• Imaging Science in Dentistry
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• 제44권4호
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• pp.301-305
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• 2014

Purpose: The purpose of this study was to compare the accuracy of postoperative maxillary cyst (POMC) diagnosis by panoramic radiographs versus computed tomography (CT) and by oral and maxillofacial radiologists versus non-specialists. Materials and Methods: Sixty-five maxillary sinuses with POMCs and 63 without any lesion were assessed using panoramic radiographs and CT images by five oral and maxillofacial radiologists and five non-specialists on a five-point scale. The areas under receiver operating characteristic (ROC) curves were analyzed to determine the differences in diagnostic accuracy between the two imaging modalities and between the two groups of observers. The intra-observer agreement was determined, too. Results: The diagnostic accuracy of CT images was higher than that of panoramic radiographs in both groups of observers (p<0.05). The diagnostic accuracy of oral and maxillofacial radiologists for each method was higher than that of non-specialists (p<0.05). Conclusion: The use of CT improves the diagnosis of POMC, and radiological training and experience leads to more accurate evaluation.