• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.133-146
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• 1996

Eastman Kodak Co. has announced the concept of photo CD System in September, 1990 With Photo CD System technology, Kodak Co. Furnishes a convinent way to view, use and store photographic images. The heart of this system is a format provides progressively higher levels of image quality to meet the demands of NTSC, PAL and HDTV video displays as well as hard copy output. Also, image professionals are instrested in the capability of Photo CD, such as a way to store image at low cost in a high-resolution digital format that can be played back on different computer platforms. Many editors wish to use Photo CD images in the printing and publishing industry. However, Photo CD images were not processed detail enhancement and some others to use in the lithographic offset printing. Therefore, in this paper discribes a method to improve the sharpness of Photo CD images.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.303-307
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• 2002

Although Synthetic Aperture Radar(SAR) is a very powerful and attractive tool, automatic interpretation of SAR images is extremely difficult because of several reason. Spatially, speckle noise reduction in SAR images is important step to interpret the SAR image at the preprocessing step. The speckle noise in SAR images is modeled to be multiplicative, and therefore, a signal-dependent noise. So, it has deflated many image-denoising algorithms that are based on additive noise model. In this paper, we propose an adaptive wavelet shrinkage method for speckle noise reduction in SAR images by analyzing the high frequency level in detail. We first decompose minutely the high frequency level to analyze the noise level. And then, we determine the weighting threshold value per the level, and layer. Finally, using those weighting threshold, we produce the efficient wavelet shrinkage method. So, this method not only reduces the speckle noise, but also preserves image detail and sharpness.

• ETRI Journal
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• v.44 no.5
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• pp.816-825
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• 2022

Nondestructive testing, which can monitor a product's interior without disassembly, is becoming increasingly essential for industrial inspection. Computed laminography (CL) is widely used in this application, as it can reconstruct a product, such as a printed circuit board, into a three-dimensional (3D) high-magnification image using X-rays. However, such high-magnification scanning environments can be affected by minute vibrations of the CL device, which can generate motion artifacts in the 3D reconstructed image. Since such vibrations are irregular, geometric corrections must be performed at every scan. In this paper, we propose a geometry calibration method that can correct the geometric information of CL scans based on the image without using geometry calibration phantoms. The proposed method compares the projection and digitally reconstructed radiography images to measure the geometric error. To validate the proposed method, we used both numerical phantom images at various magnifications and images obtained from real industrial CL equipment. The experiment results confirmed that sharpness and contrast-to-noise ratio (CNR) were improved.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.1
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• pp.71-78
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• 1990

This research was made to investigate the change of the image layer and of the vertical and horizontal magnification on the Panelipse radiographic image by the control of profile index. Using the Panelipse, a series of 60 exposures were taken with the steel balls placed in the holes of the plastic model plate, and then evaluated by 4 observers. Two points were assigned for a reading of sharp, one for middling sharp, and zero for unsharp. Each ball image then could be given a total reader score of 0 to 8. The author analyzed the image layer as defined by a sharpness score of 6 or more. The results obtained were as follows: As the profile index was increased, the shape of the image layer was not changed, and the width of the image layer was increased, and the position of the layer shifted away from the rotation center. As the profile index was increased, the ranges of vertical and horizontal magnification was increased, especially the ranges of horizontal magnification was greater than that of vertical magnification.

• Journal of radiological science and technology
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• v.28 no.2
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• pp.111-115
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• 2005

The quality of image from the system that creates medical images by using X-ray depends on the various different reasons such as the X-ray generator, the subject and the image transmission medium. In other words, thereare various factors existing that can influence on the quality of image from the moment when the X-ray is generated and until the final image is created. Therefore, the operator who creates images at the clinical site should make continuous evaluation and observation from the final image. There are various methods of evaluating the medical images, but it is assumed that the MTF measurement method can be suitable for measuring actual or effective resolution. So in this study, the MTF measurement method by using X-ray film has been avoided and the MTF features according to the deterioration of the X-ray system have been measured by using the software (the program used Borland C++ builder software and LEAD tools software) that can measure the MTF of the digital medical images. As the result of this measurement, it has been found out through the MTF graph that the resolution and sharpness from the old x-ray generator with a many years of using and many numbers of times of using were deteriorated for the quality of image comparing to those from the new system. Also a simple and easy measurement method for the MTF from the digital medical images can be obtained in this study.

• Journal of radiological science and technology
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• v.27 no.3
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• pp.25-29
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• 2004

Among the digital radiography systems, the computed radiography Image Plate Detector System is most frequently being used for the general radiography and also this system commonly diffracts the x-ray images since it is the system that is influenced by the light diffusion from the fluorescent substances. In this study, by using the X-ray Generator, a comparative analysis has been made between 2 different models of computer radiography image plate investigate each model's resolution and sharpness through the modulation transfer function(MTF) measurement. For the analysis, two image plates for general radiography one Fuji ST-VN model(more than 3years old) and one Fuji ST-VL model(less than 2years old) that are currently being used in "Hospital A" were sampled for the MTF measurement here. As the experimental method for this study, the resolution chart method has been carried out by using X-ray generator. Also all the experimental data were printed out by laser printer and measured by microdensitometer. As the results of the experiment carried out in this study, some differences have been found between the two different IP models and Fuji ST-VL has shown its excellence in both of the resolution and the sharpness fields.

• Journal of Broadcast Engineering
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• v.17 no.6
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• pp.933-944
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• 2012

In this paper, we propose a new method to convert a low-resolution depth map into its high-resolution one called distance transform-based bilateral upsampling. Since the proposed method controls the spatial domain weighting function based on distance transform values of the depth map, it increases the input depth map resolution while preserving edge sharpness. The proposed method is composed of three main steps: distance transform, spatial weighting control, and image interpolation. Experimental results show that our method outperforms the conventional bilateral upsampling in terms of the quality of output depth maps.

• Journal of Information Processing Systems
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• v.12 no.1
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• pp.35-45
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• 2016

To resolve the problems of Poisson/impulse noise, blurriness, and sharpness in degraded X-ray images, a novel and efficient enhancement algorithm based on X-ray image fusion using a discrete wavelet transform is proposed in this paper. The proposed algorithm consists of two basics. First, it applies the techniques of boundary division to detect Poisson and impulse noise corrupted pixels and then uses the Wiener filter approach to restore those corrupted pixels. Second, it applies the sharpening technique to the same degraded X-ray image. Thus, it has two source X-ray images, which individually preserve the enhancement effects. The details and approximations of these sources X-ray images are fused via different fusion rules in the wavelet domain. The results of the experiment show that the proposed algorithm successfully combines the merits of the Wiener filter and sharpening and achieves a significant proficiency in the enhancement of degraded X-ray images exhibiting Poisson noise, blurriness, and edge details.

• Journal of radiological science and technology
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• v.24 no.2
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• pp.13-17
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• 2001

When most patients are diagnosed with the quiet progressed hepatoma which often would make the operation impossible, the Interventional Radiology hepatic artery embolization is an extremely useful method for such patients. An existence of the malfunction is evaluated by gaining a portal vein image as a delayed phase image after injecting a contrast media into the superior mesenteric artery. However, it is difficult to make a definite judgement due to the extended exposure time with the peristalsis and the intestine gas obstructing the sharpness of the image when the Patient exposure time increases and due to the increased usage of contrast media and its side effect. The portal vein can be evaluated by obtaining the MIP image after reconstructing a 3-dimensional personal computer setting using the 2-dimensional from an enhancement abdomen CT image that is almost a requisite in operation to a hepatoma patient. Such method nay prevent a decrease in the quality of image based upon the time delay and intestine gas; also, because the patient exposure dose and contrast media usage may be reduced, it is a new, valuable way to decide the operational matter of hepatic artery embolization on a pre-angiography.

• Journal of Broadcast Engineering
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• v.9 no.2
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• pp.131-141
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• 2004

Current binocular stereoscopic displays cause visual discomfort when objects with large disparities are present in the scene. One solution for improving visual comfort is synthetic depth-of-field processing, which simulates the characteristics of a human visual system. With this technique, visual comfort is improved by blurring portions of the background and/or foreground in the scene. However, this technique has the drawback of degrading overall image quality because the blurring is typically applied to both left and right images. To alleviate the visual discomfort, we propose a novel disparity-based asymmetrical filtering technique. Proposed technique applies the filtering to the image of one eye only, and controls the blur level according to the disparity information between stereoscopic images. We investigate the effects of this technique on stereoscopic video by measuring visual comfort and apparent sharpness. Our results indicate that disparity-based asymmetrical filtering can improve visual comfort of stereoscopic video while it maintains apparent sharpness if unfixated regions with large disparities are blurred under the appropriate filtering condition.