• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.181-181
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• 2004

3 차원 형상측정기술(3-D Profile Measurement Method)은 가공품의 치수검사 및 형상측정 등의 공학분야뿐만 아니라 최근에는 의류산업 및 의학산업은 물론 오락산업의 가상현실 구현 등 여러 분야로 점차 사용이 확대되고 있다. 이러한 요구를 만족시킬 수 있는 광학을 바탕으로 한 비접촉 3 차원 형상측정방법(Non-contacting 3-D Profile Measuring Method)은 고속, 고정밀도 측정이 가능하기 때문에 활발히 연구되고 있다. 광학을 이용한 대표적인 3 차원 비접촉 측정방법의 하나인 영사식 무아레는 그림자식 무아레의 단점인 격자의 크기가 측정물체보다 커야 한다는 점과 측정물체와 격자사이의 거리 제한 문제를 해결하였으며, 위상이동법을 사용함으로서, 무아레 무늬 형태의 영향을 받지 않고 측정이 가능해졌다.(중략)

• Journal of Distribution Science
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• v.7 no.2
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• pp.63-87
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• 2009

The conclusions shown by this study are as follows: Firstly, Despite the similarity of the objective distance caused by the geographic distance and cultural similarities. it is found that the psychic distance factor still exists. Secondly, a new affective factor of psychic distance has been noted. As to the shaping method, even though culture and psychic distance involve homeogenic factors, psychic distance is more complex in that it is affected not only by cultural changes but also by other affective factors. Culture is a very significant factor, which can have an effect on forming psychic distance, but it is short of being a measurement variable for measuring psychic distance. Thirdly, psychic distance can have a direct effect on customers' buying response. If it is just a belief shared among the people of a nation, it can't become an important notion.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.656-666
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• 1995

본 논문에서는 물체위로 투사된 line stripe으로부터 물체의 표면 정보를 추출하기 위해 2-D Grip paper를 이용해 캘리브레이션하는 방법이 제안되었다. 카메라의 이미지평면과 카메라의 가시범위에 있는 3차원 실세계간의 Projective Tranformation과정에서는 목표물과 이미지 평면사이의 거리나 각도 등이 정보를 실제로 측정해서 알고 있어야만 카메라와 실세계간의 캘리브레이션을 수행할 수 있다. 그러나 이미 크기나 거리를 알고 있는 Grid paper를 이용하면 카메라의 파라미터들에 대한 추정이나 카메라와 실세계간의 측정을 하지 않고서도 목표물위로 투사된 line stripe에 대한 정보를 얻을 수 있고 이를 이용해 물체의 표면에 대한 정보를 얻을 수 있다. 이미 지평면에 투영된 격자패턴에서 구한 교차점들의 위치를 이용해 실제 위치를 찾아낸다. 실제로 레이져스캐너를 이용해 물체위로 line stripe을 투사한 후, 위에서 제시한 방법을 통해 3차원 정보를 구하는 실험결과는 양호하였다.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.1
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• pp.125-133
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• 2024

In this paper, we propose a volume measurement method for an object based on depth image. The object volume is measured by calculating the object height and width in actual units through the depth image. The object area is detected through differences between the captured and background depth images. The volume of the 2×2 pixel area, formed by four adjacent pixels using the depth information associated with each pixel, is measured. The object volume is measured as the sum of the volumes for whole 2×2 areas in the object area. In simulation results, the average measurement error for the object volume is 2.1% when the distance from the camera is 60cm.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 1998.11a
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• pp.45-49
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• 1998

3차원 스캐너 또는 스테레오 비전 등으로부터 입력된 거리 정보(Range Data)를 실제 응용프로 프로그램에 사용하기 위한 가상객체(Virtual Character)로 만들기 해서 는 우선 메쉬(mesh) 형태로 변환하는 작업 이 필수적이며, 기법들은 수십년 동안 활발히 연구되어 왔다. 많이 이용되는 방법은 초기 입력된 거리영상들의 각각의 점들이 연결관계 및 구조에 대한 정보를 입력 시점에서 알 수 있으므로, 각 면에 대해서는 쉽게 메쉬를 생성하여, 2차원 측정 단면 중심의 부조 형태로 메쉬를 활용하고 있지만. 3차원 가상객체가 요구되는 경우에는 측정단면별로 형성된 결과들을 하나의 메쉬로 생성하기 위해서는 짜깁기(Zippering)와 같은 어려운 작업이 추가로 필요하다. 본 논문에서는 개선된 3차원 행진입방체 방법과 간략화 기법을 적용하여 짜깁기(Zippering)을 사용하지 않고 가상객체를 생성하는 방법을 소개하려 한다.

• Broadcasting and Media Magazine
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• v.26 no.2
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• pp.9-17
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• 2021

LiDAR는 조사된 빛이 피사체에 반사되어 돌아오는 시간을 측정하여 거리를 측정하는 장비로서, 넓은 영역과 긴 거리에 걸쳐 실세계의 정밀한 3차원 정보를 포인트 클라우드 데이터로 제공해 준다. 이러한 대용량 포인트 클라우드 데이터는 자율주행 자동차, 로봇, 3차원 지도 제작 등 컴퓨터 비전 기술을 이용하는 다양한 분야에 널리 활용될 수 있다. 그러나 유리 구조물을 포함하는 피사체를 LiDAR로 촬영하는 경우, 유리면에서 빛의 반사로 인한 가상의 포인트가 생성되어 실제 3차원 정보를 왜곡하는 문제가 있다. 포인트 클라우드의 후속 처리를 효율적으로 수행하기 위하여, 이러한 왜곡을 제거하는 전처리 기술이 필요하다. 본 고에서는 LiDAR의 취득 원리와 3차원 포인트 클라우드의 특성을 고찰하고, 유리 반사로 인한 왜곡된 가상의 포인트를 자동으로 검출하고 제거하는 새로운 연구 주제를 소개한다.

• Journal of Gastric Cancer
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• v.6 no.3
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• pp.161-166
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• 2006

Purpose: Recently, the incidence of early gastric cancer (EGC) patients is rapidly increased in Korea. However, they're often not perceptible by surgical palpation or inspection. The aim of this study is 1) to develope a software that can locate the tumor and measure the mucosal distance from an anatomic landmark to the tumor using CT gastrography and 2) to compare the distance measured by the developed software with the distance measured by the pathologic findings. Materials and Methods: Between January 2004 and September 2005, sixty patients (male=45, female=15, mean 57.8 years old) estimated for EGC with preoperative CT scans and undergone gastrectomies in Kyungpook National University Hospital were enrolled in this study. Preoperative CT scans were performed after insufflations of room air via 5 Fr NG tube. The scans included the following parameters: (slice thickness/reconstruction interval: 0.625 mm, kVp: 120, mAs: 200). 3D volume rendering and measurement of the surface distance from the pylorus to the EGC were performed using the developed software. Results: The average difference between the lesion to pylorus distances measured from pathologic specimens and CT gastrography was $5.3{\pm}2.9\;mm(range,\;0{\sim}23\;mm)$. The lesion to pylorus distance measured from CT gastrography was well correlated with that measured from the pathologic specimens (r=0.9843, P<0.001). Conclusion: These results suggest that the surface distance from an anatomic landmark to the EGC can be measured accurately by CT gastrography. This technique could be used for preoperative localization of early gastric carcinomas to determine the optimal extent of surgical resection.

• Smart Media Journal
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• v.7 no.2
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• pp.15-22
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• 2018

Pupil tracking technologies can be used as an efficient information provider means that provides convenience to the user by connecting with a smart device. In this paper, we measure the distance of user gaze point using the pupil tracking device which produced by Pupil-labs, also shows the experimental result with analyzing accuracy and precision. Based on that the pupil gaze point location which tracked by pupil tracking device is compared with object target in terms of error. Since the mobile pupil tracking device is also one kind of camera, we have to perform the calibration before using the device. Not only generally used 2-dimensional calibration, but also 3-dimensional calibration method is explained. To get the improved accuracy of 2-dimensional calibration result, the 3-dimensional calibration set an imaginary plane and executes the calibration in various 3-dimensional spaces. To show the efficiency of 3-dimensional calibration, we analyze the experimental result. It also introduces various using methods and information that can be obtained through the device.

• Progress in Medical Physics
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• v.14 no.2
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• pp.131-140
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• 2003

As the importance of accuracy in measurings of 3-D anatomical structures continues to be stressed, an objective and quantitative of assessing image quality and accuracy of 3-D volume-rendered images is required. The purpose of this study was to evaluate the quantitative accuracy of 3-D rendered images obtained with MDCT, scanned at various scanning parameters (scan modes, slice thicknesses and reconstruction slice thickness). Twelve clinically significant points that play an important role for the craniofacial bone in plastic surgery and dentistry were marked on the surface of a dry human skull. The direct distances between the reference points were defined as gold standards to assess the measuring errors of 3-D images. Then, we scanned the specimen with acquisition parameters of 300 mA, In kVp, and 1.0 sec scan time in axial and helical scan modes (pitch 3:1 and 6:1) at 1,25 mm, 2.50 mm, 3.75 mm and 5.00 mm slice thicknesses. We performed 3-D visualizations and distance measurements with volumetric analysis software and statistically evaluated the quantitative accuracy of distance measurements. The accuracy of distance measurements on the 3-D images acquired with 1.25, 2.50, 3,75 and 5.00 mm slice thickness were 48%, 33%, 23%, 14%, respectively, and those of the reconstructed 1.25 mm were 53%, 41%, 43%, 36% respectively. Meanwhile, there were insignificant statistical differences (P-value<0.05) in the accuracy of the distance measurements of 3-D images reconstructed with 1.25 mm thickness. In conclusion, slice thickness, rather than scan mode, influenced the quantitative accuracy of distance measurements in 3-D rendered images with MDCT. The quantitative analysis of distance measurements may be a useful tool for evaluating the accuracy of 3-D rendered images used in diagnosis, surgical planning, and radiotherapeutic treatment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.510-514
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• 1994

This paper deals with an application of neural network to camera calibration with wide angle lens and 2-D range finding. Wide angle lens has an advantage of having wide view angles for mobile environment recognition ans robot eye in hand system. But, it has severe radial distortion. Multilayer neural network is used for the calibration of the camera considering lens distortion, and is trained it by error back-propagation method. MLP can map between camera image plane and plane the made by structured light. In experiments, Calibration of camers was executed with calibration chart which was printed by using laser printer with 300 d.p.i. resolution. High distortion lens, COSMICAR 4.2mm, was used to see whether the neural network could effectively calibrate camera distortion. 2-D range of several objects well be measured with laser range finding system composed of camera, frame grabber and laser structured light. The performance of 3-D range finding system was evaluated through experiments and analysis of the results.