• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.281-285
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• 1996

In this paper, I made visual inspection system using Vision Board and it is consist of an illuminator (a fluorescent lamp), image input device(CCD(Charge)Coupled Device) camera), image processing system(Vision Board(FARAMVB-02), image output device(videomonitor, printer), a measuring instrument(TELMN1000). Length measurement by visual inspection system is used 100mm gauge block instead of calculating distance between camera and object, it measured horizontal and vertical length factor from 400mm to 650mm by increasing 50mm. In this place, measured horizontal and vertical length factor made use of length measurement of a injection. A measuring instrument used to compare a measured length of a injection visual inspection system with it. In conclusion, length measurement of a injection compared a measuring instrument withvisual inspecion system using length factor of 100mm guage block. Maximum error of length compared two devices a measuring instrument with visual inspection system is 0.55mm. And operation program is made up Borland C++ 3.1. By changing, it is applied to various uses.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.11a
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• pp.116-120
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• 1991

Technique of length measurement error is widely used in the accuracy assessment of CMMS(Coordinate measuring machines) and machine tools, as it is simple and direct measurement within the working volume of a machine. In this paper, a new method is proposed for the evaluation of the length measurement error in relation to the volumetric accuracy. lD, 2D, and 3D measuring lines are considered for recpective length measurement error: 1D, 2D, and 3D length measurement uncertainties are evaluated from volumetric accuracy. The relationship between the volumetric accuracy md length measurement error to is discussed. PC based system for length measurement error evaluation and simulation is developed.

• Current Optics and Photonics
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• v.5 no.4
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• pp.402-408
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• 2021

An off-axis system refers to an optical system in which the optical axis and normal vector at the vertex of each surface do not match. The most important specification in an optical system is its focal length. Among the various methods for measuring the focal length, the most suitable method for the off-axis system is the method that adopts magnification. However, head-mounted display (HMD) optics must be measured while considering the virtual image distance, which is not infinity owing to product characteristics. For the virtual image distance, a camera with a focusing function was used. By measuring HMD optics via this magnification method, the error generated in this measurement was 0.68% of the HMD's focal length, which is within the 1%-3% range of the conventionally permitted design error for the focal length allowed at the optical design stage. Therefore, it can be verified that the measurement accuracy of the method proposed in this study is sufficiently feasible in practice.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.11
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• pp.126-134
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• 1997

In this study, We made visual inspection system using Vision Board. It is consist of an illuminator (a fluorescent lamp), image input device (CCD (Charge-Coupled Device) camera), image processing system(Vision Board(FARAMVB-02)), image output device (video monitor, printer), and a measuring instrument(TELMN1000). Length measurement by visual inspection system make use of 100mm guage block(instead of calculating distance between a camera and a object). It measured horizontal and vertical length factor from 400mm to 650mm by increasing 50mm. In this place, measured horizontal and vertical length factor made use of length measure- ment of a injection. A measuring instrument used to ompare a measured length of a injection visual inspection system with it. In conclusion, length measurement of a injection compared a measuring instrument with visual inspecion system using length factor of 100mm gauge block. We find that maximum error of length is 0.55mm when it compar with the measuring value of two devices(FARAMVB-02, TELMN1000). Program of visual inspection system is made up Borland C++3.1.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.10
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• pp.151-156
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• 1997

A laser measurement system, a modified Michelson interferometer, which can accurately measure high speed length and displacement of servomechanisms by detecting a phase shift in the measurement beam using an optical interference was developed. A frequency stabilized laser source and a 20 fold frequency interpolation and digitizing circuit were applied to the system. The refra- ctive index of the ambient air was calibrated through the Edlens formula. The system achieved a resolution of /40, 16nm, a maximum allow-able measurement speed of 600nm/sec, and a length measure- ment range of 1500 mm. Performance of the system was evaluated on the machining center in short and long length measurements.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.792-801
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• 1996

A thinning algorithm -based image analysis technique was developed to measure corn root lengths. The root length measurement method was evaluated by comparing thread lengths measured by the image analysis system with actual thread lengths. The length measurement method accurately estimated actual thread lengths (less than 2% calculated error). Also, a rapid root length density measurement procedure, which utilizes the above root length measurement method, was developed to estimate corn root length density without washing the roots. Root length densities estimated from the cut soil surface of core samples taken from the field were paired with the root length densities determined from washed roots from the same soil core sample. A linear relationship between these two values was expected and was found. Eliminating the root washing procedure reduces the time required for measuring corn root length density substantially.

• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.82-86
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• 1990

A camera type optical bench system equipped with a lens collimator and an image analyzer is fabricated to measure the equivalent focal length and distortion of lenses. This system is automatized by the computer which controls stepping motors. A nodal slide optical bench system equipped with an off axis reflective collimator is fabricated and improved by using rotating arms and air bearing system. distortion measurement on a wide angle lens using the camera method and the nodal slide method is reported. Defocusing error in the distortion measurement with the nodal slide optical bench is analyzed and improved by iteration method to search the correct image point.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.145-149
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• 1997

A laser mesurement system, a modified Michelson interferometer,which can accurately measure high speed length and position of servomechanisms by detecting a phase shift in the measurement beam using an optical interference was developed. A frequency stabilized laser source and a 20 fold frequency interpolation and digitizing circuit were applied to the system. The refractive index of the ambient air was calibrated through the Edlen's formula. The system achieved a resolution of .lambda./40,16nm, a maximum allowable measurement speed of 600 mm/sec, and a length measurement range of 1500mm. Performance of the system was evaluated on the machining center in short and long length measurements

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.547-550
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• 2005

Gauge blocks are the most widely used material measure in length field in industry. The gauge block interferometer, which is the gauge block measuring system, comprises Twyman-Green type interferometer optics and light sources having precisely known wavelengths. This paper describes the work done for advancing the measurement system and automating the measurement process. The advancing of the system was done mainly by exchanging the spectral lamp with the frequency stabilized lasers, and the automation of measurement was achieved by modifying the hardware and developing the automatic measuring software. As the results of this work, the contrast of interferometric fringes of gauge blocks longer than 100 mm s enhanced about 20 times, and the measurement time has reduced down to 50% by automation.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.28 no.2
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• pp.471-489
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• 1998

For the successful endodontic treatment, root canal should be cleaned thoroughly by accurate mechanical and chemical canal preparation and sealed completely with canal filling material without damaging the periapical tissues. The accuracy of the root canal length measurement is a prerequisite for the success of the endodontic treatment, and the root canal length is often determined by the standard periapical radiographs and digital tactile sense. In this study, the accuracy and the clinical usefulness of Digora/sup (R)/, an intraoral digital imaging processor and the conventional standard radiographs were compared by measuring the length from the top of the file to the root apex. 30 single rooted premolars were invested in a uniformly sized blocks and No.25 K-file was inserted into and fixed in each canal. Each block was placed in equal distance and position to satisfy the principle of the bisecting angle and paralleling techniques and Digora/sup (R)/ system's image and standard periapical radiographs were taken. Each radiograph was examined by 3 different observers by measuring the length from top of the file to the root apex and each data was compared and analyzed. The results were as follows; 1. In the bisecting angle technique, the average difference between the Digora/sup (R)/ system and standard periapical radiograph was 0.002 mm and the standard deviation was 0.341 mm which showed no statistically significant difference between the two systems(p>0.05). Also, in the paralleling technique, the average difference between these two system was 0.007 mm and the standard deviation was 0.323 mm which showed no statistically significant difference between the two systems(p>0.05). 2. In Digora/sup (R)/ system, the average difference between the bisecting angle and paralleling technique was -0.336 mm and the standard deviation was 0.472 mm which showed a statistically significant difference between the two techniques(p<0.05). Also, in the standard periapical radiographs, the average difference between the bisecting angle and paralleling technique was 0.328 mm and the standard deviation was 0.517 mm which showed a statistically significant difference between these two techniques(p<0.05). 3. In Digora/sup (R)/ system and the standard periapical radiographs. there was a statistically significant difference between the measurement using the bisecting angle technique and the actual length(p<0.05), But there was no statistically significant difference between the measurement using the paralleling technique and the actuallength(p>0.05). In conclusion. the determination of the root canal length by using the Digora/sup (R)/ system can give us as good an image as the standard periapical radiograph and using the paralleling technique instead of the bisecting angle technique can give a measurement closer to the actual canal length. thereby contributing to a successful result. Also. considering the advantages of the digital imaging processor such as decreasing the amount of exposure to the patient. immediate use of the image. magnification of image size. control of the contrast and brightness and the ability of storing the image can give us good reason to replace the standard periapical radiographs.