• Title/Summary/Keyword: Dimensional precision

Search Result 1,404, Processing Time 0.033 seconds

Engineered Surface Characterization by Space Series Function (공간 계열 함수를 이용한 가공표면의 특성 연구)

  • 홍민성
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1996.04a
    • /
    • pp.521-525
    • /
    • 1996

  • An attempt is made to characterize and synthesize engineered surfaces. The proposed method is not only an analytical tool to characterize but alsoto generate/synthesize three-dimensional surfaces. The developed method expresses important engineered surface characteristics such as the autocorrelation or pwoer spectrum density functions in terms of the two-dimensional autoregressive coefficients.

  • PDF

A comparison of the precision of three-dimensional images acquired by 2 digital intraoral scanners: effects of tooth irregularity and scanning direction

  • Anh, Ji-won;Park, Ji-Man;Chun, Youn-Sic;Kim, Miae;Kim, Minji
    • The korean journal of orthodontics
    • /
    • v.46 no.1
    • /
    • pp.3-12
    • /
    • 2016

  • Objective: The purpose of this study was to compare the precision of three-dimensional (3D) images acquired using iTero$^{(R)}$(Align Technology Inc., San Jose, CA, USA) and Trios$^{(R)}$(3Shape Dental Systems, Copenhagen, Denmark) digital intraoral scanners, and to evaluate the effects of the severity of tooth irregularities and scanning sequence on precision. Methods: Dental arch models were fabricated with differing degrees of tooth irregularity and divided into 2 groups based on scanning sequence. To assess their precision, images were superimposed and an optimized superimposition algorithm was employed to measure any 3D deviation. The t-test, paired t-test, and one-way ANOVA were performed (p < 0.05) for statistical analysis. Results: The iTero$^{(R)}$ and Trios$^{(R)}$ systems showed no statistically significant difference in precision among models with differing degrees of tooth irregularity. However, there were statistically significant differences in the precision of the 2 scanners when the starting points of scanning were different. The iTero$^{(R)}$ scanner (mean deviation, $29.84{\pm}12.08{\mu}m$) proved to be less precise than the Trios$^{(R)}$ scanner ($22.17{\pm}4.47{\mu}m$). Conclusions: The precision of 3D images differed according to the degree of tooth irregularity, scanning sequence, and scanner type. However, from a clinical standpoint, both scanners were highly accurate regardless of the degree of tooth irregularity.

  • https://doi.org/10.4041/kjod.2016.46.1.3 인용 PDF KSCI

Development of 3Dimensional Inspection system for Bicycle frame using CCD Camera (자전거 프레임 형상 검사를 위한 비젼을 이용한 3차원 측정시스템의 개발)

  • 여인재;박희재;박춘열
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1994.10a
    • /
    • pp.492-498
    • /
    • 1994

  • The bicycle production process mainly consists of welding process of pipes and its quality is determined by geometrical symmetry of arrangement of welded pipes. Hence, manual quality control of bicycle frames was very inefficient and required much time in dimentional inspection and does not reserve high precision. In this paper we introduce a method of fast and accurate dimensional inspection of bicycle frame using the Stereo Vision system and related some image processing techniques.

  • PDF