• Nuclear Engineering and Technology
• /
• v.48 no.3
• /
• pp.799-804
• /
• 2016

A miniature X-ray tube based on a carbon-nanotube electron emitter has been employed for the application to a dental radiography. The miniature X-ray tube has an outer diameter of 7 mm and a length of 47 mm. The miniature X-ray tube is operated in a negative high-voltage mode in which the X-ray target is electrically grounded. In addition, X-rays are generated only to the teeth directions using a collimator while X-rays generated to other directions are shielded. Hence, the X-ray tube can be safely inserted into a human mouth. Using the intra-oral X-ray tube, a dental radiography is demonstrated where the positions of an X-ray source and a sensor are reversed compared with a conventional dental radiography system. X-ray images of five neighboring teeth are obtained and, furthermore, both left and right molar images are achieved by a single X-ray shot of the miniature X-ray tube.

• Journal of Biomedical Engineering Research
• /
• v.25 no.6
• /
• pp.551-556
• /
• 2004

The purpose of this study was to suggest a systematic and scientific method for measurement of children's growth development, in which the accuracy of existing diagnosis method has not been concretely examined yet. The most popular method for diagnosis of children's growth is to analyze the opening degree of growth plate in each joint by X-ray image. However, X-ray method has some disadvantages; it is impossible to measure the diagnosis of growth periodically and repeatedly due to the radiation problem. Hence, this study introduced a profile analysis and the algorithm of analyzing the image of growth plate with the BUA(Broadband Ultrasound Attenuation) of calcaneus, to verify the possibility of alternative ultrasonic method harmless to human body. We obtained the images of growth plate in proximal tibiae, phalanges, and calcanei of 269 children (7∼16 years old) with X-ray. And the image of growth plate in calcanei was also obtained front those children with ultrasound. The results showed that the time of the opening degree of growth plate in each joint was almost consistent between X-ray and ultrasonic images. Also, the images of growth plate measured by X-ray and ultrasound showed the high correlation. Therefore, it is expected that the algorithm of ultrasonic profile analysis introduced in this study can replace the existing X-ray method to measure the growth plate correctly.

• Journal of information and communication convergence engineering
• /
• v.22 no.2
• /
• pp.165-171
• /
• 2024

In this study, we present a novel approach for enhancing chest X-ray image classification (normal, Covid-19, edema, mass nodules, and pneumothorax) by combining contrastive learning and machine learning algorithms. A vast amount of unlabeled data was leveraged to learn representations so that data efficiency is improved as a means of addressing the limited availability of labeled data in X-ray images. Our approach involves training classification algorithms using the extracted features from a linear fine-tuned Momentum Contrast (MoCo) model. The MoCo architecture with a Resnet34, Resnet50, or Resnet101 backbone is trained to learn features from unlabeled data. Instead of only fine-tuning the linear classifier layer on the MoCopretrained model, we propose training nonlinear classifiers as substitutes for softmax in deep networks. The empirical results show that while the linear fine-tuned ImageNet-pretrained models achieved the highest accuracy of only 82.9% and the linear fine-tuned MoCo-pretrained models an increased highest accuracy of 84.8%, our proposed method offered a significant improvement and achieved the highest accuracy of 87.9%.

• Journal of Radiation Protection and Research
• /
• v.41 no.2
• /
• pp.111-115
• /
• 2016

Background: The scattered photons cause reduction of the contrast of radiographic image and it results in the degradation of the quality of the image. In order to acquire better quality image, an anti-scattering x-ray gird should be equipped in radiography system. Materials and Methods: The X-ray anti-scattering grid of the inclined type based on the hybrid concept for that of parallel and focused type was tested by MCNP code. The MCNPX 2.7.0 was used for the simulation based test. The geometry for the test was based on the IEC 60627 which was an international standard for diagnostic X-ray imaging equipment-Characteristics of general purpose and mammographic anti-scatter grids. Results and Discussion: The performance of grids with four inclined shielding material types was compared with that of the parallel type. The grid with completely tapered type the best performance where there were little performance difference according to the degree of inclination. Conclusion: It was shown that the grid of inclined type had better performance than that of parallel one.

• Journal of Korea Multimedia Society
• /
• v.18 no.7
• /
• pp.806-817
• /
• 2015

The contrast limited adaptive histogram equalization(CLAHE) is an advanced method for the histogram equalization which is a common contrast enhancement technique. The CLAHE divides the image into sections, and applies the contrast limited histogram equalization for each section. X-ray images can be classified into three areas: skin, bone, and air area. In clinical application, the interest area is limited to the skin or bone area depending on the diagnosis region. The CLAHE could deteriorate X-ray image quality because the CLAHE enhances the area which doesn't need to be enhanced. In this paper, we propose a new method which automatically determines the clip limit of CLAHE's parameter to improve X-ray image quality using fuzzy logic. We introduce fuzzy logic which is possible to determine clip limit proportional to the interest of users. Experimental results show that the proposed method improve images according to the user's preference by focusing on the subject.

• Journal of Welding and Joining
• /
• v.32 no.6
• /
• pp.1-7
• /
• 2014

For the resistance spot welds of CR1180 and GA1180 TRIP steels, the weld quality evaluation method using the digitalized X-ray transmission imaging apparatus was investigated in comparison with the crosssectional examination method. In the case of the resistance spot welding of CR1180, three circular regions, such as WZ(white zone), GZ(grey zone) and DZ(dark zone), appeared on X-ray image and they corresponded to the diameters of indentation mark, nugget and corona bond, respectively. The variation of X-ray transmission thickness due to the thickness variation of the weld seemed to be mainly responsible for the formation of those contrasts. The X-ray image contrast formed from the variation of transmission thickness at the outer border line of DZ could also enable the inspections of the notch shape, nonuniformity of the welding pressure and spatter from its sharpness, concentricity and the normal straight line, respectively. The X-ray image of the resistance spot weld of galvannealed GA1180 TRIP steel was very similar to that of CR1180 TRIP steel except the crown shaped outer border line of DZ which was considered to be due to the melting behavior of zinc having the boiling temperature even lower than the melting temperature of steel.

• Journal of Biomedical Engineering Research
• /
• v.10 no.3
• /
• pp.243-252
• /
• 1989

In this study, medical images, which are X-ray image and CT image, are compressed by the adam live coding technique. The medical images may be treated as special ones, because they are different from general images in many respects. The statistical characteristics that medical images only have in transform domain are analyzed, and then the improved quantization method is proposed for medical images. For chest X-ray image and CT head image, the better results are obtained by the improved adaptive coding technique.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.741-745
• /
• 1991

This paper describes a feature extraction in digitized chest X-ray image and CT head Image. There are Extraction, Thresholding, Region G rowing, Split-Merge and Relaxation in feature extraction technique. In this study, Region Growing System was realized and Fuzzy Set Theory was applied in order to extract the vague region which the conventional method has difficulties in extracting. The performance of proposed algorithm was proved by being applied to chest X-ray image and CT head image.

• Journal of the Korean Society of Radiology
• /
• v.6 no.1
• /
• pp.39-45
• /
• 2012

Conventional periphery radiography system has a various problem such as patient dose and the pain of X-ray examination. In this paper, to solve these problems, we suggested insertional miniature x-ray system and we verified the feasibility of this system. First, we performed the Geant4 x-ray simulation to design x-ray collimator and filter to use miniature x-ray tube and we decided optimized thickness of filter and collimator. Also, we measured x-ray spectrum using CdTe detector and PX4 module to verify simulation results. Also, we acquired teeth image of fabricated phantom using conventional dental x-ray and prosed miniature x-ray system. As a results, our system has good image quality as compared to those of conventional systems. Our evaluation of the proposed system indicates that it can be potentially very useful for dental imaging.

• Journal of radiological science and technology
• /
• v.42 no.3
• /
• pp.167-173
• /
• 2019

The Cobey method and the modified Cobey method are most commonly used in clinical practice. Therefore, the purpose of this study was to investigate the radiological differences between Cobey and modified Cobey and provide radiographic information about changes of hindfoot image with X-ray entrance center and tube angle change in modified Cobey. This study was performed on foot and ankle phantom. First, for image comparison of Cobey and modified Cobey, the images obtained by applying the same X-ray entrance center to the ankle joint were compared and analyzed. Second, in the modified Cobey, the X-ray entrance center is set as ankle joint and lateral malleolus. The X-ray tube angle was varied from $10^{\circ}$ to $40^{\circ}$ at $5^{\circ}$ intervals for each X-ray entrance center. The images obtained by varying the X-ray tube angle from $10^{\circ}$ to $40^{\circ}$ at intervals of $5^{\circ}$ for each X-ray entrance center were compared and analyzed. The irradiation conditions were the same with 110 kVp, 200 mA, 10 ms, and 110 cm of source - image receptor distance (SID). Image evaluation was performed by two radiologists. Measurements were made on the lateral point, middle point, and calcaneus width based on a hypothetical line parallel to the calcaneal tuberosity. Data were analyzed by using descriptive statistics as the mean of the distance to each measurement location. The modified Cobey was longer than the Cobey by an average of 3 to 4 mm lateral and medial points, and the calcaneus width was similar (ICC = 0.939). In modified Cobey method, when the X-ray entrance center is ankle joint, the lateral point is about 3 mm and the medial point is about 4.3 mm longer than lateral malleolus. Also, when the X-ray tube angle is more than $20^{\circ}$, the degree of distortion is large. The ICCs for the lateral, medial point, and calcaneus width were 0.998, 0.961, and 0.997, respectively, as the X-ray entrance center and tube angle were changed. There was no significant difference between Modified Cobey and Cobey. Modified Cobey showed no need to compensate the $20^{\circ}$ detector angle of the Cobey. In addition, we suggest that tube angle should be limited within $20^{\circ}$ when modified Cobey is performed.