• Journal of Korea Game Society
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• v.15 no.2
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• pp.159-168
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• 2015

This paper introduces effective noise removal method for medical ultrasound volume data. Ultrasound volume data need to be filtered because it has a lot of noise. Conventional 2d filtering methods ignore information of adjacent layers and conventional 3d filtering methods are slow or have simple filter that are not efficient for removing noise and also don't equally operate filtering because that don't take into account ultrasound' sampling character. To solve this problem, we introduce method that fast perform in parallel bilateral filtering that is known as good for noise removal and adjust proportionally window size depending on that's position. Experiments compare noise removal and loss of original data among average filtered or biliteral filtered or adaptive biliteral filtered ultrasound volume rendering images. In this way, we can more efficiently and correctly remove noise of ultrasound volume data.

• Journal of the Korean Society of Radiology
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• v.10 no.1
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• pp.45-51
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• 2016

The purpose of this study was tried to remove the noise and improve the spatial resolution in the computed tomography (CT) by using anisotropic 2-dimensional (2D) diffusion based filter. We used 4-channel multi-detector CT and american association of physicists in medicine (AAPM) phantom was used for CT performance evaluation to evaluate the image quality. X-ray irradiation conditions for image acquisition was fixed at 120 kVp, 100 mAs and scanned 10 mm axis with ultra-high resolution. The improvement of anisotropic 2D diffusion filtering that we suggested firstly, increase the contrast of the image by using histogram stretching to the original image for 0.4%, and multiplying the individual pixels by 1.2 weight value, and applying the anisotropic diffusion filtering. As a result, we could distinguished five holes until 0.75 mm in the original image but, five holes until 0.40 mm in the image with improved anisotropic diffusion filter. The noise of the original image was 46.0, the noise of the image with improved anisotropic 2D diffusion filter was decreased to 33.5(27.2%). In conclusion improved anisotropic 2D diffusion filter that we proposed could remove the noise of the CT image and improve the spatial resolution.

• Journal of KIISE:Software and Applications
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• v.35 no.10
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• pp.600-607
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• 2008

This paper proposes a robust human detection method irrespective of their pose variation using the multiple oriented 2D elliptical filters (MO2DEFs). The MO2DEFs can detect the humans regardless of their poses unlike existing object oriented scale adaptive filter (OOSAF). To overcome OOSAF's limitation, we introduce the MO2DEFs whose shapes look like the oriented ellipses. We perform human detection by applying four different 2D elliptical filters with specific orientations to the 2D spatial-depth histogram and then by taking the thresholds over the filtered histograms. In addition, we determine the human pose by using convolution results which are computed by using the MO2DEFs. We verify the human candidates by either detecting the face or matching head-shoulder shapes over the estimated rotation. The experimental results showed that the accuracy of pose angle estimation was about 88%, the human detection using the MO2DEFs outperformed that of using the OOSAF by $15{\sim}20%$ especially in case of the posed human.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.253-256
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• 2001

본 논문에서는 전처리 과정에서 잡음의 효과적 처리를 위해 기존의 필터 방식들이 가지는 단점인 경계 부분의 블러링 현상을 줄이고 정확한 에지 위치를 보존할 수 있는 비등방성 확산 필터를 사용하여 CT나 MRI 2차원 영상 슬라이스들을 만들어내고 이 슬라이스들을 3차원 데이터 셋으로 구성하여 3차원 공간의 볼륨 데이터로 시각적인 영상정보를 얻는데 있다.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.931-934
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• 2003

DWT(Discrete Wavelet Transform)를 2차원 하드웨어로 구현하기 위해서 많은 하드웨어와 실행시간이 들기 때문에 효율적인 구조가 중요하다. 그래서, 이 논문에서는 2차원 DWT에 대한 효율적인 하드웨어 이용률과 크기의 감소, 완벽한 레지스터 이용률, 규칙적인 데이터 흐름으로 필터 길이의 확장을 쉽게 할 수 있도록 구조를 개선하고, 개선된 구조를 VHDL로 검증하였다.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2002.11a
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• pp.343-349
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• 2002

본 논문에서는 모듈성과 확장성을 갖는 시스톨릭 어레이를 이용한 FIR(finite impulse response) 디지털필터의 구현에 대하여 기술한다. 차분방정식 혹은 전달함수가 주어질 때 기본소자를 이용한 FIR 디지털필터 설계를 위한 2차원 DG(dependence graph)로부터 1차원 시스톨릭 어레이를 유도한 후 유도된 시스톨릭 어레이를 RT 수준에서 VHDL로 모델링하여 동작을 검증하였다 검증된 시스톨릭 어레이를 이용한 FIR 디지털필터는 Hynix에서 제공하는 0.35$\mu\textrm{m}$ 셀 라이브러리와 FPGA칩인 XCV200E을 사용하여 합성 및 구현되었다.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.343-349
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• 2002

본 논문에서는 모듈성과 확장성을 갖는 시스톨릭 어레이를 이용한 FIR(finite impulse response) 디지털필터의 구현에 대하여 기술한다. 차분방정식 혹은 전달함수가 주어질 때 기본소자를 이용한 FIR 디지털필터 설계를 위한 2차원 DG(dependence graph)로부터 1차원 시스톨릭 어레이를 유도한 후 유도된 시스톨릭 어레이를 RT 수준에서 VHDL로 모델링하여 동작을 검증하였다. 검증된 시스톨릭 어레이를 이용한 FIR 디지털필터는 Hynix에서 제공하는 0.35$\mu\textrm{m}$ 셀 라이브러리와 FPGA칩인 XCV200E을 사용하여 합성 및 구현되었다.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.53-58
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• 2016

In this paper, we propose a novel quadratic Kalman filter based object tracking algorithm using moving pictures. Quadratic Kalman filter, which is introduced recently, has not yet been applied to the problem of 3-dimensional (3-D) object tracking. Since the mapping of a position in 2-D moving pictures into a 3-D world involves non-linear transformation, appropriate algorithm must be chosen for object tracking. In this situation, the quadratic Kalman filter can achieve better accuracy than extended Kalman filter. Under the same conditions, we compare extended Kalman filter, unscented Kalman filter and sequential importance resampling particle filter together with the proposed scheme. In conculsion, the proposed scheme decreases the divergence rate by half compared with the scheme based on extended Kalman filter and improves the accuracy by about 1% in comparison with the one based on unscented Kalman filter.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.5
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• pp.117-126
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• 2010

In order to obtain more clear x-ray images, an antiscatter grid, which can absorb the scattered rays, is employed. In the high-resolution direct digital radiography, however, the artifacts due to the grid are visible. In this paper, the grid artifacts are reduced by applying simple 1-dimensional low-pass filters in the spatial domain based on the rotated grid. Since the proposed algorithm does not use any detection scheme for the artifact frequencies and discrete Fourier transforms for 2-dimensional filters, it can simply and fast reduce the grid artifacts. The performance using the order 1 average filter is compatible to that of using 2-dimensional filters in the frequency domain.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.534-537
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• 2011

분리형 필터는 메모리 접근 및 연산량을 O($N^2$)에서 O(N)으로 최적화하는 기법이다. GPGPU를 이용한 필터기반의 영상처리에 분리형 필터를 적용하면 2차원 apron 영역이 2개의 1차원 apron 영역으로 이 되기 때문에 메모리 최적화 측면에서 유리하다. 본 논문은 GPGPU를 이용한 분리형 필터에 슬라이딩 윈도우 형태의 지역 메모리 관리 기법을 적용하여 apron 발생을 최소화하는 구조를 제안하고 실험을 통해 저성능 메모리 환경에서 최대 17.9% 성능향상이 있었으며, 메모리 성능이 50% 낮아지는 경우에도 전체성능 감소도 최대 9%수준으로 안정적임을 확인하였다.