• Journal of radiological science and technology
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• v.41 no.5
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• pp.391-396
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• 2018

The purpose of this study was to compare and analyze the patient dose according to the distance between the X-ray tube focus and the image receptor, and to propose a new method for quantitatively evaluating the image quality. Using this quantitative evaluation method, the optimal distance for increasing x-ray image quality with low radiation dose was estimated between source and image receptor in Rib series radiography. Phantom images were obtained by changing the distance between focus and image receptor (100 cm and 180 cm). The patient radiation dose was estimated using entrance surface dose and dose area product. In order to evaluate image quality objectively, a non - reference image evaluation method was employed with paper and salt noise and Gaussian filter. As a result of this study, when the SID was changed from 100 cm to 180 cm, the entrance surface dose decreased by 4 ~ 5 times and the dose area product decreased by 3 times. In addition, there is no significant difference in image quality between of SID 180 cm and SID 100 cm. In conclusion, it was demonstrated that performing the rib series radiography at SID 180 cm is an optimal method to reduce the exposure dose and improve the image quality.

• Journal of Science Education
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• v.34 no.1
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• pp.33-46
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• 2010

The purpose of this study was to find out the image as science teachers recognized by pre-service science teachers. The data was collected from 312 pre-service science teachers from Kyungpook National University in Daegu and participants were asked to write about the image of science teachers they liked most and least in their secondary school years freely. The result of this research was as follows. The image as science teachers categorized 2 factors: science instructional situation, image of science teacher. Each factor was subdivided into more detailed ones. First of all, 'science instructional situation' category subdivided into lesson style, teaching-learning materials, teaching methods, and class atmosphere. In lesson style, 'experiment' and 'observation' gained the most favorable comments, and questioning-answering gained the least. In teaching-learning materials, print materials such as handouts, worksheets, reports were the most liked, and 'writing on the blackboard' was the least liked. In teaching methods, the 'detailed and systematic explanation of the theory and concepts' was preferred to rote learning and memorization lacking explanation. In class atmosphere, friendly and free atmosphere was the most preferred, and uncomfortable, boring one was the least preferred. Secondly, in 'image of the science teachers' category and 'quality as the teachers' sub-category, thoughtful and considerate teachers who respect students' personality was the most preferred. On the contrary, they didn't prefer teachers who were indifferent and humiliated students. Finally in 'characteristics of the teachers' sub-category, the participants liked clear, energetic voice, and mild expression, and they didn't like formal style, overly fancy clothes, etc. Based on the result of this study, more empirical study on the teachers' image is needed, and the thoughts of educational administrators, students, parents, and teachers should be reflected because an undesirable teacher can be advised and get opportunity to be a better teacher.

• Current Optics and Photonics
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• v.7 no.3
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• pp.237-247
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• 2023

In middle- and long-distance imaging systems, due to the atmospheric turbulence caused by temperature, wind speed, humidity, and so on, light waves propagating in the air are distorted, resulting in image-quality degradation such as geometric deformation and fuzziness. In remote sensing, astronomical observation, and traffic monitoring, image information loss due to degradation causes huge losses, so effective restoration of degraded images is very important. To restore images degraded by atmospheric turbulence, an image-restoration method based on improved compound multibranch feature fusion (CMFNetPro) was proposed. Based on the CMFNet network, an efficient channel-attention mechanism was used to replace the channel-attention mechanism to improve image quality and network efficiency. In the experiment, two-dimensional random distortion vector fields were used to construct two turbulent datasets with different degrees of distortion, based on the Google Landmarks Dataset v2 dataset. The experimental results showed that compared to the CMFNet, DeblurGAN-v2, and MIMO-UNet models, the proposed CMFNetPro network achieves better performance in both quality and training cost of turbulent-image restoration. In the mixed training, CMFNetPro was 1.2391 dB (weak turbulence), 0.8602 dB (strong turbulence) respectively higher in terms of peak signal-to-noise ratio and 0.0015 (weak turbulence), 0.0136 (strong turbulence) respectively higher in terms of structure similarity compared to CMFNet. CMFNetPro was 14.4 hours faster compared to the CMFNet. This provides a feasible scheme for turbulent-image restoration based on deep learning.

• International Journal of Advanced Culture Technology
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• v.7 no.4
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• pp.242-245
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• 2019

In this paper, watermark embedding technique was proposed to securely conceal the watermark in color cover image by applying the spatial encryption technique. The embedded watermak can be extracted from stego-image without loss. The quality of the stego-image is very good. So it is not possible to visually distinguish the difference between the original cover image and the stego-image. The validity of the proposed technique was verified by mathematical analysis. The proposed watermark embedding technique can be used for intellectual property protection, military, and medical applications that require high security.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.492-497
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• 2009

Computer-Generated Hologram (CGH) is made for three dimensional image of a virtual object. Error diffusion method is used for the phase quantization of CGH, and it is known to be effective to the image quality improvement of the reconstructed image. However, the image quality of the reconstructed image from the CGH using error diffusion method depends on the selection of error diffusion coefficient. In this paper, we derived the relational expression to obtain the error diffusion coefficient from the position of the input object and size of the input object for CGH. As a result, the method of this thesis was able to obtain an excellent reconstructed image compared with the case to derive the error diffusion coefficient from only the position of the input image.

• Journal of Korean Elementary Science Education
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• v.32 no.4
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• pp.527-534
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• 2013

This study investigated elementary school teachers' understanding of the image formation by converging lens, pinholes camera, mirror and water. In each case teachers were asked to draw the ray diagram to indicate the position of the image. Teachers' ray diagrams were analyzed in accordance with the scientific process of image formation. Results of analysis showed that teacher's conceptions were classified into five levels for each situation. And most of the teachers were in level 3 and level 4 in each case. Because they had difficulties in the appling scientific conception(propagating path of light, diffused reflection from each object point, role of the eye, ray tracing) to finding location of image. Also most of teachers didn't know how to apply the law of reflection and refraction to each situation. The study finally discussed the teacher training program of the optical image.

• The Korean Journal of Community Living Science
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• v.12 no.1
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• pp.51-62
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• 2001

The purpose of the study were to investigate the differences of Image on male and female\\` The purpose of the study were to investigate the differences of Image on male and female´ Contemporary folk costume of Female College Students according to their life styles and their major. The data were collected from 300 female college students in Cheongju city through self-administerd questionnaires, and were analyzed by frequencies, Cronbach´s $\alpha$, F-test, Factor Analysis, Cluster Analysis, one way ANOVA and Duncan Test. The results of the study were as follows: The image on male and female´ Contemporary folk costume were found to include four different dimensions- fashion, activity, gracefulness, ability. There were not significant differences between dimensions of image on male and female´ contemporary folk costume according to student´s major. Life styles were classified five types. There were significantly different at dimensions of fashion and gracefulness, ability between life style dimensions and image on males´ contemporary folk costume. There was significantly different at dimension of gracefulness between life style dimensions and image on females´ contemporary folk costume.

• Journal of the Korean Data and Information Science Society
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• v.18 no.2
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• pp.385-399
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• 2007

In many image processing applications, a random noise makes some trouble since most video enhancement functions produce visual artifacts if a priori of the noise is incorrect. The basic difficulty is that the noise and the signal are difficult to be distinguished. Typical unsharp masking (UM) enhances the visual appearances of images, but it also amplifies the noise components of the image. Hence, the applications of a UM are limited when noises are presented. This paper proposed statistical algorithms based on parametric and nonparametric tests to adaptively enhance the image feature and the noise combining while applying UM. With the proposed algorithm, it is made possible to enhance the local contrast of an image without amplifying the noise.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.1224-1227
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• 2002

In this paper, we propose a composition method of the template image whose detection performance does not have incorrect detection and improves also on the tough photography conditions of the outdoors, rainy weather and night. This research was done to measure a relative position between a spreader and a target container with image processing to realize full-automatic quayside gantry cranes. By the proposal method, we confirmed that the template image for object detection has a contour image more effective than a gray image.

• Journal of Korean Elementary Science Education
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• v.28 no.3
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• pp.245-262
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• 2009

This research was to examine the understandings of elementary school teachers on the phenomena related to light and image, and to survey their perception change related to learning contents of optics. The subjects were selected from the elementary teachers who were enrolled in a graduate course, 'Science education seminar' at an education college located in Chungchungbuk-Do, South Korea. Among the five students who exposed their perceptions clearly in the class, the three of them were selected who agreed to the proposal of the case study. To achieve the purpose of this study, semi-structured interviews following the conception test with the 3 elementary teachers were conducted. During the analysis of the data, additional interviews by phone, e-mail, and internet messenger were conducted if necessary. According to the results, all of the elementary school teachers lacked the scientific conceptions of the phenomena related to light and image. Unfortunately, their learning experiences did not help them to understand the scientific concepts. During the interviews, the teachers recognized the importance of the viewpoints of seeing, image, cognition of light, point light source to understand the phenomena related to light and image.