• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.735-741
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• 2003

A simplified view of array design and application process was introduced. Array design is critical to achieve a successful phased array measurements. A planar microphone array is designed to produce optimum performance and also to fit economic requirement in integrating data acquisition system. Certain performance characteristics are of primary concern when designing arrays. These characteristics include array resolution, spatial aliasing and array sidelobe suppression. Every array has its directional pattern that shows such characteristics. Assuming that a monopole source is located in center, beam-patterns have been simulated varying measurement conditions such as number of sensors. array aperture size, distance between array and source, frequency of interest and so on. Sensor correction was conducted on very channel using magnitudes and phased of FRF with respect to a reference microphone channel. Then with a spiral type array, measurements have been made with two point sources of same frequency in order to investigate array resolving abilities. It is observed that higher frequency source achieves better resolution than lower one does.

• Journal of radiological science and technology
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• v.30 no.3
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• pp.251-257
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• 2007

Medical imaging zero-phase-sequence component in estimation for picture that is gotten that importance weight of digital device is increased day by day at the same time also so much important. Special quality about resolution uses Modulation Transfer Function by representative method to evaluate sharpness on important element in image quality. Get MTF converting slit, differentiating this making composition ESF edge method uses Excel by edge method in this study to be composition LSF get in fourier to informed measuring mean universally. Such method is considered that can help in principle grasping of step before make Program using C language as many as Matlab.

• Korean Journal of Remote Sensing
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• v.34 no.1
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• pp.89-99
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• 2018

Spatial downscaling is often applied to coarse scale satellite products with high temporal resolution for environmental monitoring at a finer scale. An area-to-point regression kriging (ATPRK) algorithm is regarded as effective in that it combines regression modeling and residual correction with area-to-point kriging. However, an open source tool or package for ATPRK has not yet been developed. This paper describes the development and code organization of an R-based spatial downscaling tool, named R4ATPRK, for the implementation of ATPRK. R4ATPRK was developed using the R language and several R packages. A look-up table search and batch processing for computation of ATP kriging weights are employed to improve computational efficiency. An experiment on spatial downscaling of coarse scale land surface temperature products demonstrated that this tool could generate downscaling results in which overall variations in input coarse scale data were preserved and local details were also well captured. If computational efficiency can be further improved, and the tool is extended to include certain advanced procedures, R4ATPRK would be an effective tool for spatial downscaling of coarse scale satellite products.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.268-274
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• 2023

Image mosaicking is one of the basic and important technologies in the field of application using images. The key of image mosaicking is to extract seamlines from a joint image. The method proposed in this paper for image mosaicking is as follows. The feature points of the images to be joined are extracted and the joining form between the two images is identified. A reference position for detection the seamlines were selected according to the joint form, and an image pyramid was created for efficient image processing. The outlines of the image including buildings and roads are extracted from the overlapping area with low resolution, and the seamlines are determined by considering the components of the outlines. Based on this, the seamlines in the high-resolution image was re-searched and finally the seamline for image mosaicking was determined. In addition, in order to minimize color distortion of the image with the determined seamline, a method of improving the quality of the mosaic image by fine correction of the mosaic area was applied. It was confirmed that the quality of the seamline extraction results applying the method proposed was reasonable.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.56-63
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• 2024

In high radiation fields, gamma cameras suffer from pulse pile-up, resulting in poor energy resolution, count losses, and image distortion. To overcome this problem, various methods have been introduced to reduce the size of the aperture or pixel, reject the pile-up events, and correct the pile-up events, but these technologies have limitations in terms of mechanical design and real-time processing. The purpose of this study is to develop a real-time gamma camera to evaluate the radioactive contamination in high radiation fields. The gamma camera is composed of a pinhole collimator, NaI(Tl) scintillator, position sensitive photomultiplier (PSPMT), signal processing board, and data acquisition (DAQ). The pulse pile-up is corrected in real-time with a field programmable gate array (FPGA) using the start time correction (STC) method. The STC method corrects the amplitude of the pile-up event by correcting the time at the start point of the pile-up event. The performance of the gamma camera was evaluated using a high dose rate ¹³⁷Cs source. For pulse pile-up ratios (PPRs) of 0.45 and 0.30, the energy resolution improved by 61.5 and 20.3%, respectively. In addition, the image artifacts in the ¹³⁷Cs radioisotope image due to pile-up were reduced.

• Journal of Korea Water Resources Association
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• v.50 no.1
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• pp.1-15
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• 2017

Information on radar rainfall with high spatio-temporal resolution over large areas has been used to mitigate climate-related disasters such as flash floods. On the other hand, a well-known problem associated with the radar rainfall using the Marshall-Palmer relationship is the underestimation. In this study, we develop a new bias correction scheme based on the quantile regression method. This study employed a bivariate copula function method for the joint simulation between radar and ground gauge rainfall data to better characterize the error distribution. The proposed quantile regression based bias corrected rainfall showed a good agreement with that of observed. Moreover, the results of our case studies suggest that the copula function approach was useful to functionalize the error distribution of radar rainfall in an effective way.

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.250-255
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• 2010

Purpose: Pincer nail is a relatively rare deformity characterized by an increase in transverse curvature along the longitudinal axis of the nail. This curvature commonly increases from proximal to distal end of nail, leading to pinching, curling, and distortion of the underlying soft tissue and resulting frequently in severe pain. Numerous surgical procedures have been reported. Preserving the width of the nail in the correction of the pincer nail is very important for functional and aesthetic reasons. We report the results of the correction of the pincer nail using autogenous dermofat graft with a good result. Methods: From May 2006 to September 2008, dermofat graft was performed in 6 patients with pincer nail. Patients were four women and two men, and the average age was 51. The affected digits were the unilateral great toes in four patients and the unilateral thumbs in two patients. Average follow-up period was 13 months. Surgical procedure was removal of nail using an elevator to avoid damage to the nail bed. An incision was created in distal portion of hyponychium. Paronychium was dissected from distal phalanx by periosteal elevator through incision of hyponychium and tunnel was made. Then dermofat grafts harvested from inguinal area were inserted into the tunnel. Finally, a silicone sheet was inserted eponychial fold for prevention of synechia. Objective assessment was evaluated by use of the width index and height index. Results: All patients reported resolution of the pain and soft tissue pinching sensation that they had before the operation. There was good adherence between the nail plate and the underlying nail bed. The nails have regrown and were corrected in a normal and flattened appearance. The width index and height index were improved. Conclusion: The autogenous dermofat graft seems to provide an effective treatment of the pincer nail with preservation of the nail matrix.

• Journal of the Korean Society of Safety
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• v.32 no.4
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• pp.100-106
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• 2017

Outline map is used for the description and reconstruction of the traffic accident. One way to produce the outline map is by adopting detailed measurements from the accident site such as final position of the vehicle and pedestrian, width of the road, and locations of the oil and tire marks. This method consumes large amount of time not to mention that of the production of detailed version as fine as the picture of the site. Aerial recording equipment so called HeliCam can produce an outline map that can substitute that of manual method with even faster production time and higher resolution. However, the produced picture have errors which are resulted by distortion due to the characteristics of camera and direction of the photographing. This paper provides correction of the distortion of oultline map produced by HeliCam using Adobe Photoshop and PC-Rect. The result showed resonable error range less than 6 cm(0.1%) for $60m{\times}30m$ area taken by HeliCam. The presented method develops outline map with small error, which is useful to traffic accident analysis, and traffic accident cases analyzed in this study were also.

• Journal of Biomedical Engineering Research
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• v.30 no.6
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• pp.461-468
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• 2009

Magnetic resonance electrical impedance tomography (MREIT) enables us to perform high-resolution conductivity imaging of an electrically conducting object. Injecting low-frequency current through a pair of surface electrodes, we measure an induced magnetic flux density using an MRI scanner and this requires a sophisticated MR phase imaging method. Applying a conductivity image reconstruction algorithm to measured magnetic flux density data subject to multiple injection currents, we can produce multi-slice cross-sectional conductivity images. When there exists a local region of fat, the well-known chemical shift phenomenon produces misalignments of pixels in MR images. This may result in artifacts in magnetic flux density image and consequently in conductivity image. In this paper, we investigate chemical shift artifact correction in MREIT based on the well-known three-point Dixon technique. The major difference is in the fact that we must focus on the phase image in MREIT. Using three Dixon data sets, we explain how to calculate a magnetic flux density image without chemical shift artifact. We test the correction method through imaging experiments of a cheese phantom and postmortem canine head. Experimental results clearly show that the method effectively eliminates artifacts related with the chemical shift phenomenon in a reconstructed conductivity image.

• Journal of Digital Convergence
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• v.14 no.8
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• pp.305-311
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• 2016

If the automated image calibration system is performed in the position of non-experts, an expert will be required in every case inefficiently. But this requires an expert only when absolutely necessary. As well as the rapid system operation and efficient workforce can be managed. Image correction to perform projector inspection and management skills and to filter SW plug-in correction is that special theater system maintenance is not only managed efficiently, but also combined image analysis techniques can improve the technical perfection. This paper is to minimize the economic loss by developing a 10-bit High-depth and high-resolution $360^{\circ}$ projection image analysis technique and is to development of the special theater calibration system to effectively support quality.