Semi-Automatic Measurement of the Airway Dimension by Computed Tomography Using the Full-With-Half-Maximum Method: a Study of the Measurement Accuracy according to the Orientation of an Artificial

Namkug Kim,Joon Beom Seo,Koun-Sik Song,Eun Jin Chae,Suk-Ho Kang 대한영상의학회 2008 Korean Journal of Radiology Vol.9 No.3

Objective: To develop an algorithm to measure the dimensions of an airway oriented obliquely on a volumetric CT, as well as assess the effect of the imaging parameters on the correct measurement of the airway dimension. Materials and Methods: An airway phantom with 11 poly-acryl tubes of various lumen diameters and wall thicknesses was scanned using a 16-MDCT (multidetector CT) at various tilt angles (0, 30, 45, and 60 ). The CT images were reconstructed at various reconstruction kernels and thicknesses. The axis of each airway was determined using the 3D thinning algorithm, with images perpendicular to the axis being reconstructed. The luminal radius and wall thickness was measured by the full-width-half-maximum method. The influence of the CT parameters (the size of the airways, obliquity on the radius and wall thickness) was assessed by comparing the actual dimension of each tube with the estimated values. Results: The 3D thinning algorithm correctly determined the axis of the oblique airway in all tubes (mean error: 0.91 0.82 ). A sharper reconstruction kernel, thicker image thickness and larger tilt angle of the airway axis resulted in a significant decrease of the measured wall thickness and an increase of the measured luminal radius. Use of a standard kernel and a 0.75-mm slice thickness resulted in the most accurate measurement of airway dimension, which was independent of obliquity. Conclusion: The airway obliquity and imaging parameters have a strong influence on the accuracy of the airway wall measurement. For the accurate measurement of airway thickness, the CT images should be reconstructed with a standard kernel and a 0.75 mm slice thickness. Objective: To develop an algorithm to measure the dimensions of an airway oriented obliquely on a volumetric CT, as well as assess the effect of the imaging parameters on the correct measurement of the airway dimension. Materials and Methods: An airway phantom with 11 poly-acryl tubes of various lumen diameters and wall thicknesses was scanned using a 16-MDCT (multidetector CT) at various tilt angles (0, 30, 45, and 60 ). The CT images were reconstructed at various reconstruction kernels and thicknesses. The axis of each airway was determined using the 3D thinning algorithm, with images perpendicular to the axis being reconstructed. The luminal radius and wall thickness was measured by the full-width-half-maximum method. The influence of the CT parameters (the size of the airways, obliquity on the radius and wall thickness) was assessed by comparing the actual dimension of each tube with the estimated values. Results: The 3D thinning algorithm correctly determined the axis of the oblique airway in all tubes (mean error: 0.91 0.82 ). A sharper reconstruction kernel, thicker image thickness and larger tilt angle of the airway axis resulted in a significant decrease of the measured wall thickness and an increase of the measured luminal radius. Use of a standard kernel and a 0.75-mm slice thickness resulted in the most accurate measurement of airway dimension, which was independent of obliquity. Conclusion: The airway obliquity and imaging parameters have a strong influence on the accuracy of the airway wall measurement. For the accurate measurement of airway thickness, the CT images should be reconstructed with a standard kernel and a 0.75 mm slice thickness.

3차원 좌표 측정기 측정 오차에 높은 온도의 측정물이 미치는 영향에 대한 연구

홍선기 국제차세대융합기술학회 2022 차세대융합기술학회논문지 Vol.6 No.6

Three dimensional coordinate measuring machine is a measuring instrument that measures size, location, direction with the sensor that has detection function of location of object on the surface by moving three dimensional space as detecting the coordinates of measurement point and running the data through computers. Three dimensional coordinate measuring machine was designed to measure geometrical characteristics of component with a complex shape on spatial coordinates, so the availability of three dimension measuring instrument is getting more important for reverse engineering, quality control of the product, ensuring reliability of product, manufacture evaluation. But measurement of precision of 3dimension measuring instrument and insufficiency of reliability make the use of 3 dimension measuring instrument harder. The measurement precision of three dimensional coordinate measuring machine can rely on the skills of the actual user, but the bigger cause is the measuring condition for measurement. Especial ly, temperature is a crucial condition and in this study, I did research on the effect that high temperature measure object affects measurement errors. As a result, The error strain and uncertainty of the measured value were large between 30 and 50 °C. So it seems to be very important to keep the condition at a standard temperature when we measure these kinds of material s. The result of this study is to minimize measurement errors on three dimensional coordinate measuring machine. and I expect it would contribute to its reliability improvement. 3차원 측정기는 물체의 표면 위치를 검출하는 기능을 가진 센서가 3차원 공간을 움직이면서 측정점을 좌 표를 검출하고 컴퓨터를 통해 그 데이터를 처리함으로써 크기나 위치, 방향 등을 측정하는 측정기이다. [ 1 ] 복잡한 형 상의 부품에 대한 기하학적 특성을 공간좌표 상에서 쉽게 측정할 수 있도록 제작된 측정기가 3차원 측정기 이며, 역설계, 제품의 품질관리, 제품의 신뢰도확보, 제품평가를 위해 3차원 측정기의 활용도가 중시되고 있다. 하지만 3 차원 측정기의 활용에 측정 정밀도 및 신뢰성 미흡은 3차원 측정기의 활용을 어렵게 한다. 3차원 좌표측정기의 측 정 정밀도는 실제 사용자의 숙련도에 의존 할 수 있으나 더 큰 원인은 측정을 위한 측정조건이라고 할 수 있다. 특히 온도는 3차원 좌표측정기의 측정에 중요한 조건이며, 본 연구에서는 고온 측정물이 측정오차에 미치는 영향 에 대해 연구하였다. 그 결과 측정값의 오차 변형률 및 불확도가 30~50℃ 사이에서는 불확도가 크게 나타났다.

안면계측법을 이용한 과도한 교합면 마모 환자의 전악 수복: 증례보고

박찬 ( Chan Park ),강동완 ( Dong Wan Kang ),정재헌 ( Jae Hun Jeong ),김희중 ( Hee Jung Kim ) 조선대학교 구강생물학연구소 2011 Oral Biology Research (Oral Biol Res) Vol.35 No.1

The patient was 58 years old male and visited for the treatment of missing teeth and aesthetic restoration resulted from abrasion. Full mouth rehabilitation with the increase of vertical dimension was planned through oral examination, radiographic examination, model examination and the evaluation of vertical dimension. The increasing amount of vertical dimension was determined 4mm by using facial measurement. Centric occlusion was determined. Then, vertical dimension was increased 4 mm on articulator. Diagnostic wax-up was conducted. To evaluate whether increase of vertical dimension is proper, follow-up after installation of provisional restoration was observed and continuous check and adjustment was conducted. In this period, prognostic poor teeth was extracted, and endodontic, periodontic treatment and implant was conducted. The group function which bear lateral force on natural teeth was set up to make stable occlusal contact at centric occlusion and reduce lateral force unfavorable to implant. After long term follow-up on patient mouth, the vertical dimension of provisional restoration was relocationed equally to final restoration. This case is reported that the patient, as mentioned above, who has decreased vertical dimension caused by excessive abrasion was recovered aesthetic, functional factors through prosthodontic treatment with increasing vertical dimension.

3D Measurement Using a Single Image for Smart Manufacturing of Microscopic Products in a Ceramic Powder Pressing Process

Hyejin S. Kim,Yoonsoo Han,김준모 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.1

Owing to the development of artificial intelligence, smart manufacturing has extensively been investigated, which has rapidly increased manufacturing productivity. The most prevalent smart manufacturing application using machine learning is product quality enhancement through surface and dimensional defect detection. Various sensors, such as stereoscopic, 2D, or 3D lasers as well as structured light sensors, have been used to perform precise thickness measurements. These sensors are expensive and they require a large space for installation in a factory, which consumes time and energy. Moreover, micro-scale dimensional measurement equipment is much more expensive and easily damaged by environmental changes such as temperature and humidity. In the beginning, we introduce a single image-based 3D measurement system using depth estimation that makes dimensional anomaly detection easy and fast. This is important for green technology because the proposed method can reduce condemned or inferior goods by detecting anomalies early and save raw materials and energy consumption. The existing method is deep learning based depth estimation. However, it is difficult for conventional depth estimation methods to predict 3D measurement directly because of the difference between depth estimation and 3D measurement. That is because inputs are discontinuous dimensional values with homogeneous textures. Conventional depth estimation is a regression task that assumes inputs are continuous. To circumvent this problem, we propose a magnifier loss. In addition, to overcome the object’s homogeneity and meet the micro-scale dimensional precision requirement, this paper proposes a novel magnifier transformation function that magnifies the homogeneous textures and micro-scale dimensional value changes. This method achieves better quantitative performance than a conventional computer vision method, stereo-matching approaches, and even a structured light sensor, which is known to be one of most accurate and expensive sensors for a 3D measurement system.

Semi-Automatic Measurement of the Airway Dimension by Computed Tomography Using the Full-With-Half-Maximum Method: a Study of the Measurement Accuracy according to the Orientation of an Artificial Airway

Kim, Namkug,Seo, Joon Beom,Song, Koun-Sik,Chae, Eun Jin,Kang, Suk-Ho The Korean Radiological Society 2008 KOREAN JOURNAL OF RADIOLOGY Vol.9 No.3

<P><B>Objective</B></P><P>To develop an algorithm to measure the dimensions of an airway oriented obliquely on a volumetric CT, as well as assess the effect of the imaging parameters on the correct measurement of the airway dimension.</P><P><B>Materials and Methods</B></P><P>An airway phantom with 11 poly-acryl tubes of various lumen diameters and wall thicknesses was scanned using a 16-MDCT (multidetector CT) at various tilt angles (0, 30, 45, and 60°). The CT images were reconstructed at various reconstruction kernels and thicknesses. The axis of each airway was determined using the 3D thinning algorithm, with images perpendicular to the axis being reconstructed. The luminal radius and wall thickness was measured by the full-width-half-maximum method. The influence of the CT parameters (the size of the airways, obliquity on the radius and wall thickness) was assessed by comparing the actual dimension of each tube with the estimated values.</P><P><B>Results</B></P><P>The 3D thinning algorithm correctly determined the axis of the oblique airway in all tubes (mean error: 0.91 ± 0.82°). A sharper reconstruction kernel, thicker image thickness and larger tilt angle of the airway axis resulted in a significant decrease of the measured wall thickness and an increase of the measured luminal radius. Use of a standard kernel and a 0.75-mm slice thickness resulted in the most accurate measurement of airway dimension, which was independent of obliquity.</P><P><B>Conclusion</B></P><P>The airway obliquity and imaging parameters have a strong influence on the accuracy of the airway wall measurement. For the accurate measurement of airway thickness, the CT images should be reconstructed with a standard kernel and a 0.75 mm slice thickness.</P>

Soft Tissue Measurement Method Using Radiopaque Material on Cone-beam Computed Tomography: An Ex Vivo Validation Study

이해석,이동원,윤정호 대한구강악안면임플란트학회 2018 대한구강악안면임프란트학회지 Vol.22 No.4

Purpose: The purpose of this study was to investigate the validity and reproducibility of a method based on cone-beam computed tomography (CBCT) technology for the visualization and measurement of gingival soft-tissue dimensions. Material and Methods: A total of 66 selected points in soft-tissue of the ex vivo head of an adult pig were investigated in this study. For the measurement of radiographic thickness (RT), wet softtissue surfaces were lightly covered with barium sulfate powder using a powder spray. CBCT was taken and DICOM files were assessed for soft-tissue thickness measurement at reference points. A periodontal probe and a rubber stop were used for the measurement of trans-gingival probing thickness (TPT). After flap elevation, actual thickness of soft-tissue (actual thickness, AT) was measured. Correlation analysis and intraclass correlation coefficients analysis (ICC) were performed for AT, TPT, and RT. Results: All variables were distributed normally. Strong significant correlations of AT with RT and TPT values were found. The two ICC values between TPT vs. AT and RT vs. AT differed significantly. Conclusion: Our results indicated that correlation of RT was stronger than that of TPT with AT. We concluded that soft tissue measurement with Ⅰ. Introduction : Previously, a noninvasive method using a radiopaque material and periapical radiography to measure the vertical length of the interdental papilla in natural teeth and implants was proposed1-3. By using radiopaque material, it was possible to demarcate soft tissue, without underexposing radiography. However, such two-dimensional information limits the assessment of the whole periodontium. The metric assessment of soft tissue dimensions around teeth and implants is of great clinical interest for the quantification and monitoring of gingival changes during therapies. Gingival soft tissue dimensions play significant roles in the assessment of whole treatment success, and thus should be monitored all through therapy. A lack of gingival thickness showed a tendency towards loss in attachment levels after traumatic, inflammatory, or surgical injuries4. Likewise, orthodontic tooth movement may adversely affect the mucogingival complex, especially at sites in which the keratinized gingiva and underlying bone appeared thin5. Acceptable methods for the accurate quantification of tissue changes when assessing new treatment modalities and materials influencing soft tissues are thus needed6. Cone-beam computed tomography (CBCT) is used routinely for imaging analyses of the maxillofacial region7. This modality provides clinicians with high-quality diagnostic images and has become an important tool in dentistry. However, the inability of CBCT to distinguish overlapped soft tissues, such as mucogingival thickness on the buccal side of alveolar bone, has limited its application exclusively to the imaging of hard maxillofacial tissues8. Several studies reported using CBCT9-12 for studying soft tissue thickness. Although validation process was not reported, these studies showed us a possibility to study delicate mucogingival soft tissue by retracting overlapped soft tissue. However, one validation study reported that soft tissues less than 0.5mm was not possible to be confirmed in spiral CT, thus making the application of spiral CT in very thin mucosa questionable13. In this study, we describe a method based on CBCT technology for the visualization and measurement of soft tissue dimensions, after demarcating the soft tissue with radiopaque material. The aim of this study was to investigate the validity and reproducibility of this method. Ⅴ. Conclusion : In conclusion, the results of the present study suggest that soft tissue measurement with CBCT and radiopaque material could be a reliable method, compared to the trans-gingival probing measurement method, with good validity and reproducibility.

입체 형상 분석을 위한 3차원 계측시스템의 활용

정희경(Jung Hee-Kyeong),이명희(Lee Myung-Hee) 한국복식학회 2005 服飾 Vol.55 No.5

The concern with three-dimensional measurement has been growing in recent years. And over the last few years, several studies have been made on three-dimensional measurement. Some of the studies using a three-dimensional measurement have focused on type of form of human body and evaluation of fitness. But there has been no study about applications of three-dimensional measurement system for shape analysis. So, the purpose of this study was to investigate about application of three-dimensional mea-surement system lot shape analysis. The instrument and tools for three-dimensional measurement was Whole Body 3D scanner(model name: Exyma-WBS2H). Analysis program used in experiment is Rapid Form 2004 PPI (INUS technology, Int, Korea). The following results were obtained; 1. The point data using three-dimensional measurement system built 3D model. 2. The three-dimensional data were used to analyze length and curvature of shape. 3. The shape using three-dimensional measurement system could be used in variety field.

3차원측정기 PMI 기법을 활용한 Drawing 생산성 향상에 대한 사례연구

홍선기,유경선,현동훈 국제차세대융합기술학회 2021 차세대융합기술학회논문지 Vol.5 No.4

수많은 제조업체들에 3차원 측정기가 보급되고, 3D 모델링(Modeling) 소프트웨어의 보급에 따라 3차원 측정기에서의 모델링(Modeling) 활용이 가속화 되고 있다. 하지만 모델링(Modeling) Data 활용으로 3차원 측정 방식에 많은 변화가 있으나. 여전히 Auto Cad 2D 도면이 필요한 상황에는 큰 변화가 없다. 현장에서 측정업무를 담당하는 작업자들에게 똑같은 도면을 보여주고 읽고 해석하라고 한다면 초급, 중급, 고급의 숙련자 모두 의견이 다를 것이고 측정도면의 이해도, 기하공차 등의 활성화로 도면은 점차적으로 복잡한 형태로 변경되어 가고 있다. 본 논문에서는 3차원측정기(CMM) PMI(Product Manufacturing information) 기법을 활용한 Drawing을 통해 품질 측정 및 생산성향상에 대한 사례를 연구하였다. 정밀 측정 산업 측정분야에서 가장 필요로 하는 핵심적인 요 소는 정확도와 측정시간이다. 이를 통해 기존 제품(Product) 측정대비 PMI Drawing 기법 활용 시 생산성 향상에 대한 개선을 확인 하였다. 3D measuring machines are being distributed to many manufacturers, and the use of modeling in 3D measuring machines is accelerating according to the spread of 3D modeling software. However, there are many changes in the 3D measurement method due to the use of modeling data. Still have Auto Cad 2D drawings There are no major changes in the necessary circumstances. If the workers in charge of the measurement work in the field are asked to show, read, and interpret the same drawings, the opinions of beginners, intermediates, and advanced experts will be different, and with the activation of understanding of the measurement plane and geometric tolerance, the drawings will gradually become more complex. It is changing. In this paper, a case of quality measurement and productivity improvement was studied through drawing using CMM (Product Manufacturing Information) technique. Accuracy and measurement time are the key factors that are most required in the field of precision measurement industry measurement. Through this, it was confirmed that productivity improvement was improved when using the PMI drawing method compared to the existing product measurement.

기계가공 부품의 품질검사용 게이지에 대한 측정불확실성에 관한연구

이갑조,오상록,김종관 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.2

Machining parts must be produced within the specification of drawing and those will be able to meet faculty and efficiency. At that time, it is very important not only precision machine or measurement technique but also the measurement technique is very important. So, the improvement of measurement technique is to be joined together at once with improvement of machining technique. Finally, the quality and value of the parts are decided by precision measurement. This paper aims to study on the measurement uncertainty when the machined parts are inspected with 3-dimensional coordinate measuring machine. The objectives are to remove an error of measurement and improve a quality of the mass products.

A nanopipette ball probe for dimensional measurement of micro-structures

So Ito,Issei Kodama,Wei Gao 한국생산제조학회 2012 한국생산제조시스템학회 학술발표대회 논문집 Vol.2012 No.10

The measurement system using a nanopipette ball probe is introduced for dimensional measurement of micrometer-scale structures. The nanopipette ball probe is consisted of thermally pulled capillary glass tube, and then a glass micro sphere with 9 μm diameter is attached at the edge of the capillary glass tube. In order to measure the distance between the edge of the probe and the surface of the measuring object, a method of shear-force detection is employed in this study. Since the shear-force detection can detect an interaction due to a water layer on the surface of the measuring object, it will be able to achieve non-contact measurement of the microstructures. During the measurement, the nanopipette ball probe is oscillated in lateral direction on its resonance frequency. The nanopipette ball probe can be detected the approaching from three axial direction by using single sensor. This paper presents the experimental investigations for performance evaluation of the nanopipette ball probe as a measurement system for dimensional measurements.