• Geomechanics and Engineering
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• 제38권1호
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• pp.29-44
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• 2024

This research investigates the effectiveness of data augmentation techniques in the automated analysis of B-scan images from ground-penetrating radar (GPR) using deep learning. In spite of the growing interest in automating GPR data analysis and advancements in deep learning for image classification and object detection, many deep learning-based GPR data analysis studies have been limited by the availability of large, diverse GPR datasets. Data augmentation techniques are widely used in deep learning to improve model performance. In this study, we applied four data augmentation techniques (geometric transformation, color-space transformation, noise injection, and applying kernel filter) to the GPR datasets obtained from a testbed. A deep learning model for GPR data analysis was developed using three models (Faster R-CNN ResNet, SSD ResNet, and EfficientDet) based on transfer learning. It was found that data augmentation significantly enhances model performance across all cases, with the mAP and AR for the Faster R-CNN ResNet model increasing by approximately 4%, achieving a maximum mAP (Intersection over Union = 0.5:1.0) of 87.5% and maximum AR of 90.5%. These results highlight the importance of data augmentation in improving the robustness and accuracy of deep learning models for GPR B-scan analysis. The enhanced detection capabilities achieved through these techniques contribute to more reliable subsurface investigations in geotechnical engineering.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.109-110
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• 2012

• 한국통신학회논문지
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• 제38B권11호
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• pp.861-869
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• 2013

본 논문에서는 정보시스템에 바이러스가 ${\lambda}$의 비율을 갖는 포아송 프로세스를 따라 도착한다고 가정한다. 정보시스템에는 바이러스를 검출하고 치료하기 위해 실시간스캔과 배치스캔의 두가지 방식으로 안티바이러스시스템을 운용하고 있다. 실시간스캔 방식에서는 바이러스가 시스템에 도착하자마자 스캔하게 되어 무한 용량의 안티바이러스시스템을 보유한 것과 같은 효과가 있다. 스캔과 치료에 소요되는 시간은 일반분포를 따르는 것으로 가정한다. 배치스캔 방식에서는 시스템 관리자가 일정한 시간 간격마다 정기적으로 시스템을 스캔하여 시스템에 존재하는 바이러스들을 동시에 치료한다. 본 논문에서는 안티바이러스시스템의 동작을 확률적으로 모형화하고 경제적으로 최적운용정책이 달성되는 조건을 유도한다. 비용 요소를 고려하여 실제적인 운용 환경에서의 시사점을 제시할 수 있는 수치예제도 제시한다.

• 대한의용생체공학회:의공학회지
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• 제7권2호
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• pp.133-138
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• 1986

Abstract In a conventional digital sector scan system in the ultrasound medical imaging, the sampling space is in the polar coordinates while the display space is in the cartesian coordinates, which necessitates a coordinate transformation process resultion process resulting the overall system very complex and bulky. In this paper we propose a new architecture of the Digital-Scan-Converter (DSC) for the ultrasound sector scan system in which sampling space is the same as the display space, so the data are displayed as they are acquired without any interpola- tion process required. To implement the above real time DSC. two frequency synthesizes with very high switching time and a low-pass filter are required. The former determines the precise location of the data points and the latter fills the gap betw- een pixels in the horizontal direction.

• 대한기계학회논문집B
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• 제25권6호
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• pp.804-810
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• 2001

Transition of flows in natural convection in a horizontal cylindrical annulus is investigated for the fluid with Pr=0.2. The unsteady streamfunction-vorticity equation is solved with finite difference method. As Rayleigh number is increased, the steady crescent-shaped eddy flow bifurcates to a time-periodic flow with like-rotating eddies. After the first Hopf bifurcation, however, a reverse transition from oscillatory to a steady flow occurs by the flow pattern variation. Hysteresis phenomenon occurs between the solution branches of up-scan and down-scan stages, and dual solutions with one steady and one oscillatory flow are found. Overall Nusselt of the flows at the flows at the down-scan stage is greater than that at the up-scan stage.

• 대한의용생체공학회:의공학회지
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• 제5권1호
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• pp.85-92
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• 1984

A new architecture of the Digital Scan Converter (DSC) for the linear-scan ultrasound medical imaging systems is proposed and its hardware implementation is reported. While the conventional DSC merely displays the acquisited data and does nor allow access to the frame memory, it is possible, in the new system, to access to the frame memory for further imaging processing so as to obtain useful information for medical diagnosis. Image processing can be performed either by a special pupose processor, or by VAX 11/780. The system is made to operate asyncronously to increase the frame rate with tags assigned to the data. The proposed DSC was designed to be used without much modification for the sector scan system as well.

• 대한핵의학회:학술대회논문집
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• 대한핵의학회 1969년도 제8차 학술대회
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• pp.11-11
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• 1969

• 대한의용생체공학회:의공학회지
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• 제11권1호
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• pp.113-120
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• 1990

In this paper, the deconvolution method utilizing a modified Wiener filter is applied for the enhancement of lateral resolution of ultrasonic B-scan Images. For this purpose, a phantom composed of wires which are 0.6mm of diameter and apart in the range between 3 to 9mm is constructed. The modified Wiener filter with optimal parameter is applied to the phantom for the analysis of ultrasonic image. The results obtained are as follows'When all parameters of the modified Wiener filter are optimal, the resolution of B-scan images is enhanced by 50 percent : Othenrise, the images are blurred, spilt at peak points, or noises are strengthened severely. When the point-spread function representing the characteristic function of the system is determined, the selection ranges of op- timum parameters may be narrowed. It is expected that the proposed method may be able to apply to clinic situations for more accurate image analysis by means of reducing the loss of important information.

• 전기의세계
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• 제31권3호
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• pp.204-208
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• 1982

The objective of this paper is to present a digital method for improving the lateral resolution of the B-scan images in the medical applications of ultrasound. The method is based upon a mathematical model of the lateral blurring caused by the finite beam width of the transducers. This model provides a simple method of applying a recursive scheme for image restoration with fast computation time. The point spread function (P.S.F.) can be measured by the reflective signals after scanning the small pins located along the depth of interest. From the measured P.S.F., one can compute the coefficient matrices of the inverse discrete-time dynamic state variable equation of the blurring process. Then, a recursive scheme for deblurring is applied to the recorded B-scan to improve the lateral resolution. One major advantage of the present recursive scheme over the transform method is in its applicability for the space-variant imaging, such as in the case of the rotational movement of transducer.

• 대한핵의학회지
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• 제33권1호
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• pp.65-75
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• 1999

목적: 종양 환자의 평가에 있어서 초고에너지 조준기를 장착하여 511 keV에 적용시킨 감마카메라로 FDG 전신 평면 영상(FDG W/B scan)을 얻어 충분한 정보를 얻을 수 있는지 알아보고 동시에 같은 카메라로 동시계수 회로를 이용한 양전자 방출 단층촬영(FDG CoDe PET)을 실시하여 그 결과를 비교하였다. 대상 및 방법: F-18 FDG를 이용하여 초고에너지 조준기와 동시계수 양전자 방출영상에 대해 각각 팬텀 실험을 실시하였고, 악성종양이 의심되거나 진단된 환자 14명을 대상으로 FDG 전신 평면 영상과 양전자 방출 단층 영상을 얻어 방사선학적 검사, 임상적 추적관찰, 조직학적 검사 등과 비교하였다. 결과: 평면 영상에서는 해상력 13.1 mm, 민감도 2638 cpm/MBq/ml, 동시계수 영상에서는 공간 해상력 7.49 mm, 민감도 5351 cpm/MBq/ml로 측정되었다. FDG CoDe PET에서 14명의 환자 중 8명에서 FDG의 섭취가 있었다. 두 방법 모두에서 FDG 섭취가 없었던 병변은 모두 CT에서 1 cm 이하 였으나 한 예에서 2 cm 크기의 전이성 림프절을 찾지 못하였다. FDG 섭취를 보였던 병변은 모두 CT상 1.5cm 이상이거나 여러 개가 모여 있는 병변이었다. FDG W/B scan은 FDG CoDe PET와 거의 비슷한 결과를 보였으나 위음성과 위양성이 1예씩 더 있었다. FDG CoDe PET에서 보였던 다수의 폐 결절과 간 결절들이 FDG W/B scan에서 한 예를 제외하고는 모두 발견되었다. 결론: 감마카메라에 의한 FDG 영상들은 악성 종양의 감별, 병기 결정, 추적검사 등에 유용하게 쓰일 수 있을 것으로 간주되며, SPECT 카메라가 널리 보급되어 있으므로 FDG 전신 평면영상과 동시계수 양전자 방출영상은 서로 보완적으로 쓰이면서 FDG의 지역 분배 공급을 통해 기존의 PET를 대신하여 FDG를 이용한 더 많은 임상적 이용 및 영상진단을 가능하게 할 것이다.