• Journal of the Korean Society of Industry Convergence
• /
• v.25 no.4_2
• /
• pp.687-697
• /
• 2022

An automated system is needed for the effectiveness of non-destructive testing. In order to utilize the radiographic testing data accumulated in the film, the types of welding defects were classified into 9 and the shape of defects were analyzed. Data was preprocessed to use deep learning with high performance in image classification, and a combination of one-stage/two-stage method and convolutional neural networks/Transformer backbone was compared to confirm a model suitable for welding defect detection. The combination of two-stage, which can learn step-by-step, and deep-layered CNN backbone, showed the best performance with mean average precision 0.868.

• Journal of radiological science and technology
• /
• v.16 no.1
• /
• pp.67-80
• /
• 1993

Recently, a large number of new screen-film systems have become available for use in diagnostic radiology. These new screens are made of materials generally known as rare-earth phosphors which have high x-ray absorption and high x-ray to light conversion efficiency compared to calcium tungstate phosphors. The major advantage of these new systesms is reduction of patient exposure due to their high speed or high sensitivity. However, a system with excessively high speed can result in a significant degradation of radiographic image quality. Therefore, th speed is important parameters for users of these system. Our aim of in this was to determine accurately and precisely the absolute speed and relative speeds of both new and conventional screen-film system. We determined the absolute speed in condition of BRH phantom beam qulity and the relative speed were measured by a split-screen technique in condition of BRH and ANSI phantom beam qulity. The absolute and the relative speed were determined for 8 kinds of screen-4 kinds of film in regular system and 7 kinds of screen-7 kinds of film in ortho system. In this study we could know the New Rx, T-MAT G has the highest film speed, also know Green system's stndard deviation of relative speed larger than blue system. It was realized that there were no relationship between the absolute speed and the blue system. It was realized that there were no relationship between the absolute speed and the relative speed in ortho or regular system.

• Imaging Science in Dentistry
• /
• v.42 no.4
• /
• pp.243-247
• /
• 2012

Purpose: This study was performed to compare the inverted digital images and film-based images of dry pig mandibles to measure the periodontal bone defect depth. Materials and Methods: Forty 2-wall bone defects were made in the proximal region of the premolar in the dry pig mandibles. The digital and conventional radiographs were taken using a Schick sensor and Kodak F-speed intraoral film. Image manipulation (inversion) was performed using Adobe Photoshop 7.0 software. Four trained examiners made all of the radiographic measurements in millimeters a total of three times from the cementoenamel junction to the most apical extension of the bone loss with both types of images: inverted digital and film. The measurements were also made in dry mandibles using a periodontal probe and digital caliper. The Student's t-test was used to compare the depth measurements obtained from the two types of images and direct visual measurement in the dry mandibles. A significance level of 0.05 for a 95% confidence interval was used for each comparison. Results: There was a significant difference between depth measurements in the inverted digital images and direct visual measurements (p>|t|=0.0039), with means of 6.29 mm ($IC_{95%}$:6.04-6.54) and 6.79 mm ($IC_{95%}$:6.45-7.11), respectively. There was a non-significant difference between the film-based radiographs and direct visual measurements (p>|t|=0.4950), with means of 6.64mm($IC_{95%}$:6.40-6.89) and 6.79mm($IC_{95%}$:6.45-7.11), respectively. Conclusion: The periodontal bone defect measurements in the inverted digital images were inferior to film-based radiographs, underestimating the amount of bone loss.

• Proceedings of the Korean Society of Medical Physics Conference
• /
• 2006.08a
• /
• pp.133-133
• /
• 2006

• Journal of The Korean Radiological Technologist Association
• /
• v.28 no.1
• /
• pp.178-185
• /
• 2002

This study was performed to investigate radiographic repeat rate on QC factors and to compare numbers of repeat film according to each year radiogical technologist. I wanted to make basic data to use QC programs in department of diagnostic radiology. This

• Journal of The Korean Radiological Technologist Association
• /
• v.29 no.1
• /
• pp.50-60
• /
• 2003

This study was performed To investigate radiographic repeat rate on QI factors and to compare numbers of repeat film according to eachyear radiogical technologist. I wanted to make basic data to use QI programs in department of diagnostic radiology, This

• Journal of radiological science and technology
• /
• v.33 no.3
• /
• pp.289-294
• /
• 2010

The purpose of this study is an evaluation of the performance of a detector under radiographic irradiation condition by fabricating the polycrystalline $HgI_2$ film detector. The polycrystalline $HgI_2$ film detectors with thickness of 210 and $320\;{\mu}m$ were fabricated by screen print technology. Measurements of X-ray sensitivity and dark current were performed for two detectors. And measurements of the linearity of X-ray response and reproducibility were performed for the detector of thickness $320\;{\mu}m$. For applied electric field strengths from 0.05 to $2\;V/{\mu}m$ to the detector of thickness $320\;{\mu}m$, the X-ray sensitivities were measured from 233 to $1,408{\times}106\;electrons/mR{\cdot}mm^2$. And the dark currents were measured from 3.2 to $118\;pA/mm^2$. Compared with values reported by Zhong Su et al., the X-ray sensitivities exhibit about two times larger than the X-ray sensitivities measured by Zhong Su et al. And the dark currents exhibit about nine times larger than the dark currents measured by Zhong Su et al. The linearity of X-ray response acquired 0.988 as a coefficient of correlation (r). Reproducibility acquired 0.002 as a coefficient of variation. This study provides the performance data of fabricated polycrystalline $HgI_2$ film detector available for an active matrix flat panel imager under radiographic irradiation condition.

• Imaging Science in Dentistry
• /
• v.34 no.3
• /
• pp.145-150
• /
• 2004

Purpose: To compare three digital radiographic imaging sensors by evaluating the visibility of endodontic file tips with interobserver reproducibility and assessing subjectively the clarity of images in comparison with the x-ray film images. Materials and Methods: Forty-five extracted sound premolars were used for this study. Fifteen plaster blocks were made with three premolars each and #8, 10, 15 K-flexofiles were inserted into the root canal of premolars. They were radiographically exposed using periapical x-ray films (Kodak Insight Dental film, Eastmann Kodak company, Rochester, USA), Digora imaging plates (Soredex-Orion Co., Helsinki, Finland), CDX 2000HQ sensors (Biomedisys Co., Seoul, Korea), and CDR sensors (Schick Inc., Long Island, USA). The visibility of endodontic files was evaluated with interobserver reproducibility, which was calculated as the standard deviations of X, Y coordinates of endodontic file tips measured on digital images by three oral and maxillofacial radiologists. The clarity of images was assessed subjectively using 3 grades, i.e. plus, equal, and minus in comparison with the conventional x-ray film images. Results: Interobserver reproducibility of endodontic file tips was the highest in CDR sensor (p < 0.05) only except at Y coordinates of #15 file. In the subjective assessment of the image clarity, the plus grade was the most frequent in CDR sensor at all size of endodontic file (p < 0.05). Conclusion : CDR sensor was the most superior to the other sensors, CDX 2000HQ sensor and Digora imaging plate in the evaluation of interobserver reproducibility of endodontic file tip and subjective assessment of image clarity.

• Imaging Science in Dentistry
• /
• v.33 no.4
• /
• pp.199-205
• /
• 2003

Purpose: To compare the visibility of the mandibular canal at the different radiographic methods such as conventional panoramic radiographs, Vimplant multi planar reformatting (MPR)-CT panoramic images, Vimplant MPR-CT paraxial images and film-based DentaScan MPR-CT images. Materials and Methods: Data of 11 mandibular dental implant patients, who had been planned treatment utilizing both panoramic and MPR-CT examination with DentaScan software (GE Medical systems, Milwaukee, USA), were used in this study. The archived axial CT data stored on CD-R discs were transferred to a personal computer with 17' LCD monitor. Paraxial and panoramic images were reconstructed using Vimplant software (CyberMed Inc., Seoul, Korea). Conventional panoramic radiographs, monitor-based Vimplant MPR-CT panoramic images, monitor-based Vimplant MPR-CT paraxial images, and film-based DentaScan MPR-CT images were evaluated for visibility of the mandibular canal at the mental foramen, 1 cm, 2 cm, and 3 cm posterior to mental foramen using the 4-point grading score. Results: Vimplant MPR-CT panoramic, paraxial, and DentaScan MPR-CT images revealed significantly clearer images than conventional panoramic radiographs. Particularly at the region 1 em posterior to mental foramen, conventional panoramic radiographs showed a markedly lower percentage of 'excellent' mandibular canal images than images produced by other modalites. Vimplant MPR-CT and DentaScan MPR-CT images did not show significant difference in visibility of the mandibular canal. Conclusion: The study results show that Vimplant and DentaScan MPR-CT imaging systems offer significantly better images of the mandibular canal than conventional panoramic radiograph.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.27 no.1
• /
• pp.17-24
• /
• 1997

The purpose of the present study was to use digital profile image features and digital image analysis of fixed-dimension bone regions, extracted from standardized periapical radiographs of the maxilla, to determine whether differences exist in alveolar bone of younger women(mean age: 59.23±7.34 years) and just menopaused women(mean age: 59.23±7.34). Periapical films were used from two groups of 20 randomly selected women. None of the subjects had a remarkable medical history. To simplify protocol, we chose one interproximal bone area between the maxillary right canine and lateral incisor for study. Ech film was digitized into a 1312 x 1024 pixel x 8 bit depth matrix by means of a Nikon 35 mm film scanner(LS-35lOAF, Japan) with fixed gain and internal dark current correction to maintain constant illumination. The scanner was interfaced to a Macintosh LC III computer(Apple Computer, Charlotte, N.C.). Area and profile orientation were selected with a NIMH Image 1.37(NIH Research Services Branch, Bethesda, Md.). Histogram features were extracted from each profile and area. The results of this study indicate that mean pixel intensities didn't differ significantly between two groups and there was a high correlarion-coefficient between digitized radiographic profile features and area features.