• Title/Summary/Keyword: Back-Projection Algorithm

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Algorithm for Moving Object Tracking from Moving Camera Using Histogram Projection (히스토그램 프로젝션을 이용한 움직이는 카메라로 부터의 이동물체 추적 알고리즘)

  • 설성욱;이희봉;김효성;남기곤;이철헌
    • Journal of the Institute of Convergence Signal Processing
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    • v.2 no.4
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    • pp.38-45
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    • 2001
  • In this paper, we propose an algorithm for moving object tracking from moving camera using histogram back program intersection(HI) and XY-projection The proposed method segments objects using histogram back projection, matches tracing objects using histogram intersection and extracts them using XY- projection. Through the simulation this paper shows that the proposed method segments. matches and tracks objects without significant error image sequences obtained by moving camera.

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Single Frame Based Super Resolution Algorithm Using Improved Back Projection Method and Edge Map Interpolation (개선된 Back Projection 기법과 에지맵 보간을 이용한 단일 영상 기반 초해상도 알고리즘)

  • Choi, Yu-Jung;Kim, Yoon
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2015.07a
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    • pp.264-267
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    • 2015
  • 본 논문에서는 개선된 고속의 Back Projection 기법과 에지맵 보간을 이용한 단일영상 기반의 초해상도(super resolution) 영상을 생성하는 알고리즘을 제안한다. 본 논문에서 제안하는 알고리즘은 영상의 색채 왜곡을 방지하기 위해 RGB 컬러 도메인에서 HSV 컬러 도메인으로 변경하여 밝기정보인 V만 이용한다. 먼저 잡음제거와 속도 향상을 위해 개선된 고속 back projection을 이용해 영상을 확대 재구성한다. 이와 함께 LoG(laplacian of gaussian) 필터링을 이용하여 에지 맵을 추출한다. 에지의 정보와 back projection의 결과를 이용하여 고해상도 영상을 재구성한다. 제안하는 알고리즘을 이용하여 복원한 영상은 부자연스러운 인공물을 효과적으로 제거하고, blur현상을 줄여 에지 정보를 보정하고 강조해준다. 또한 실험을 통해 제안하는 알고리즘이 기존의 보간법과 전통적인 back projection 결과보다 주관적인 화질이 우수하고 객관적으로 우수한 성능을 나타내는 것을 입증한다.

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A Study on Autofocus Method for Back-Projection Algorithm under the Squint Mode in Synthetic Aperture Radar (스퀸트 모드 SAR 영상 형성을 위한 역투영 알고리즘에서의 자동초점 기법 적용 연구)

  • Hwang, Jeonghun;Kim, Whan-Woo
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.7
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    • pp.81-89
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    • 2017
  • Autofocus(AF) Method is essential to overcome the performance degradation due to motion measurement errors under airborne SAR environment. In this paper, back-projection algorithm(BPA) is applied to SAR raw data acquired under the squinted mode, and preprocessing algorithm of AF for BPA is investigated. To apply AF to SAR image effectively, image backplane rotation method and doppler location alignment function for BPA are proposed. The proposed method is applied to SAR raw data acquired in a flight test and shows excellent performance improvement in real data.

Super Resolution Algorithm Based on Edge Map Interpolation and Improved Fast Back Projection Method in Mobile Devices (모바일 환경을 위해 에지맵 보간과 개선된 고속 Back Projection 기법을 이용한 Super Resolution 알고리즘)

  • Lee, Doo-Hee;Park, Dae-Hyun;Kim, Yoon
    • KIPS Transactions on Software and Data Engineering
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    • v.1 no.2
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    • pp.103-108
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    • 2012
  • Recently, as the prevalence of high-performance mobile devices and the application of the multimedia content are expanded, Super Resolution (SR) technique which reconstructs low resolution images to high resolution images is becoming important. And in the mobile devices, the development of the SR algorithm considering the operation quantity or memory is required because of using the restricted resources. In this paper, we propose a new single frame fast SR technique suitable for mobile devices. In order to prevent color distortion, we change RGB color domain to HSV color domain and process the brightness information V (Value) considering the characteristics of human visual perception. First, the low resolution image is enlarged by the improved fast back projection considering the noise elimination. And at the same time, the reliable edge map is extracted by using the LoG (Laplacian of Gaussian) filtering. Finally, the high definition picture is reconstructed by using the edge information and the improved back projection result. The proposed technique removes effectually the unnatural artefact which is generated during the super resolution restoration, and the edge information which can be lost is amended and emphasized. The experimental results indicate that the proposed algorithm provides better performance than conventional back projection and interpolation methods.

Phantom Evaluation and Development of Photoacoustic Tomography Imaging System using Unfocused Ultrasound Transducer and Back-Projection Algorithm (역투사 알고리듬과 비촛점 트랜스듀서를 적용한 광음향 단층영상 장치개발과 팬텀실험)

  • Ryu, Sang-Hun;Kim, Do-Hyun;Song, Chul-Gyu
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.12
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    • pp.2349-2351
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    • 2010
  • Photo Acoustic Tomography (PAT) is a hybrid imaging modality which combines high contrast of optical imaging and spatial resolution of ultrasound imaging, thus it is suitable to image biological tissue noninvasively. Laser-induced photoacoustic signals were measured from a sample by means of an unfocused ultrasound transducer, then PAT image was reconstructed based on a universal back-projection algorithm. To evaluate the feasibility of our system, phantom test was performed, consequently, the PAT images obtained using our system showed highly analogous shape and volume with those of the phantom. This result demonstrated that our system can provide a powerful tool for imaging the substructure of biological tissue in non-invasive manner.

Imaging Method in Time Domain for Bistatic Forward-Looking Radar in Short Range Application (근거리 Bistatic 전방 관측 레이다의 시간 영역 영상화 기법)

  • Sun, Sun-Gu;Cho, Byung-Lae;Lee, Jung-Soo;Park, Gyu-Churl;Ha, Jong-Soo;Han, Seung-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.11
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    • pp.1054-1062
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    • 2011
  • This study describes the time domain imaging algorithm which can be well applied to short-range UWB(ultra wideband) bistatic radar. In the imaging method of SAR technology, the frequency domain method is well applied to the areas which satisfy far-field condition. However in the near-field environment, the image quality is not good due to phase error. However back-projection method based on time domain is well applied to short-range imaging radar. Meanwhile because its processing time is very long, real time-processing is very difficult. To resolve this problem FFBP(Fast Factorized Back-Projection) was proposed. Using the raw data gathered on field we implemented back-projection and FFBP method. Then image quality and processing time were analyzed using these methods.

CT Image Reconstruction of Wood Using Ultrasound Velocities II - Determination of the Initial Model Function of the SIRT Method -

  • Kim, Kwang-Mo;Lee, Jun-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.33 no.5 s.133
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    • pp.29-37
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    • 2005
  • A previous study verified that the SIRT (simultaneous iterative reconstruction technique) method is more efficient than the back-projection method as a CT algorithm for wood. However, it was expected that the determination of the initial model function of the SIRT method would influence the quality of CT image. Therefore, in this study, we intended to develop a technique that could be used to determine an adequate initial model function. For this purpose, we proposed several techniques, and for each technique we examined the effects of the initial model function on the average errors and the CT image at each iteration. Through this study, it was shown that the average error was decreased and the image quality was improved using the proposed techniques. This tendency was most pronounced when the back-projection method was used to determine the initial model function. From the results of this study, we drew the following conclusions: 1) The initial model function of the SIRT method should be determined with careful attention, and 2) the back-projection method efficiently determines the initial model function of the SIRT method.

Shape Measurement and Representation of 3-D Curved Objects using Simple Back-Projection algorithm (단순역투영법을 이용한 3차원 곡면물체의 형상계측 및 표현)

  • 최종수;김덕수
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.22 no.1
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    • pp.61-67
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    • 1985
  • The new computer vision system which can reconstruct contours of parallel fault planes with horizon of 3-D curved objects has been developed. With the system, the shape of 3-D objects was measured by Simple Back-Projection algorithm which is a fundamental one in C.T.(Computed Tomography). And, the curvature in differential geometry characterizes any curve. Devising it, the method to represent each contour of 3-D curved objects with the system is described in this paper.

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RECONSTRUCTION OF LIMITED-ANGLE CT IMAGES BY AN ADAPTIVE RESILIENT BACK-PROPAGATION ALGORITHM

  • Kazunori Matsuo;Zensho Nakao;Chen, Yen-Wei;Fath El Alem F. Ah
    • Proceedings of the IEEK Conference
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    • 2000.07b
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    • pp.839-842
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    • 2000
  • A new and modified neural network model Is proposed for CT image reconstruction from four projection directions only. The model uses the Resilient Back-Propagation (Rprop) algorithm, which is derived from the original Back-Propagation, for adaptation of its weights. In addition to the error in projection directions of the image being reconstructed, the proposed network makes use of errors in pixels between an image which passed the median filter and the reconstructed one. Improved reconstruction was obtained, and the proposed method was found to be very effective in CT image reconstruction when the given number of projection directions is very limited.

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Correction of Continuous Motion Effects for Airborne FMCW-SAR System (항공기 기반 FMCW-SAR 시스템의 연속이동효과 보정)

  • Hwang, Ji-hwan;Jung, Jungkyo;Kim, Duk-jin;Kim, Jin-Woo;Shin, He-Sub;Ok, Jae-Woo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.28 no.5
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    • pp.410-418
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    • 2017
  • Results of an analysis of the continuous motion effect for FMCW-SAR system and a signal processing to correct it are presented in this paper. SAR images reconstructed by back-projection algorithm are included as well. To analyze how platform velocity and sampling frequency affect the continuous motion effect, FMCW signal model was used, and the signal processing in time-doppler(t, $k_u$) domain was adopted. Then, back-projection algorithm and modified matched-filter was used to reconstruct SAR images, and it was validated using measured data by airborne FMCW-SAR system in X-band frequency.