• Title/Summary/Keyword: distance transform

Search Result 432, Processing Time 0.032 seconds

Numerical and Experimental Analyses of the Aerodynamic Characteristics of a Counter Rotating Axial Fan (엇회전식 축류홴의 공력 특성에 관한 전산 해석 및 실험)

  • Cho, Jin-Soo;Won, Yu-Phil;Lee, Moon-Cheol
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.24 no.3
    • /
    • pp.325-337
    • /
    • 2000
  • A study was done on the numerical and experimental analyses of the aerodynamic characteristics of a counter rotating axial fan. The numerical analysis uses the frequency domain panel method developed for the aerodynamic analysis of interacting rotating systems, which is based on the unsteady lifting surface panel method. Each stage of interaction involves the solution of an isolated rotor, the interaction being done through the Fourier transform of the induced velocity field. Numerical results showed good agreements with other experimental data for single and counter rotating propeller systems. And they were compared with the experimental results of the counter rotating axial fan studied in the present paper. The performance test was carried out based on the Korean Standard (KS B 6311). It was focused on the relative efficiency increase of a counter rotating system for a single rotating one, and effects of the axial distance between the front and rear rotors on overall fan performances were investigated. As a result, it was shown that the counter rotating axial fan has the efficiency 14% higher than the single rotating one at peak efficiency points.

A new Implementation of Perceptual LPC Cepstrum and its Application to Speech Recognition (인지 LPC cepstrum의 새로운 구현 및 음성인식에의 적용)

  • Kim, Jin-Young;Choi, Seong-Ho
    • The Journal of the Acoustical Society of Korea
    • /
    • v.15 no.5
    • /
    • pp.61-64
    • /
    • 1996
  • To improve the performance of a recognition system, namely the recognition rate, we propose a hew implementation of perceptual distance using LPC cepstrum(perceptual cepstrum, PLC). The PLC is caculated by convolution of a usual LPC cepstrum and a perceptual lifter(PL). To caculate PL, we define a new weighting function in the linear frequency domain considering the frequency scale(Bark-scale) characteristics. The PL is the inverse Fourier transform of the exponents of the weighting function. We verified our method through the speech recognition experiments. The performance of PLC was compared with that of the rasied sine liftering method.

  • PDF

A Study on Real-time Montage System Design using Contents Based Image Retrieval (내용 기반 영상 검색을 이용한 실시간 몽타주 시스템 디자인에 관한 연구)

  • Bae, Seong-Joon;Choi, Hyeon-Seok;Kim, Nac-Woo;Kim, Tae-Yong;Choi, Jong-Soo
    • 한국HCI학회:학술대회논문집
    • /
    • 2006.02b
    • /
    • pp.577-582
    • /
    • 2006
  • 본 논문에서는 내용 기반 영상 검색 기술을 이용하여 사용자가 원하는 영상을 쉽게 찾아내고, 이를 자동 재구성함으로써, 영화 미학의 핵심 중 하나인 몽타주 기법을 사용자 중심의 관점에서 구현하고자 한다. 본 논문에서 제안하는 실시간 몽타주 시스템은 이산 푸리에 변환(Discrete Fourier Transform)을 이용해 사용자가 선택한 영상의 특징을 찾고, 유클리디안 거리(Euclidean Distance)를 이용해 데이터베이스에 있는 영상과 유사도를 비교함으로써, 빠르고 효과적으로 사용자가 원하는 영상을 검색할 수 있다. 또한 카메라 트래킹에 의해 실시간으로 사용자의 움직임 영상을 취득하고, 취득된 영상을 검색된 사용자의 영상과 함께 자동 재구성함으로써, 손쉽게 사용자의 의도에 맞춘 영상 재구성을 하게 된다. 본 시스템은 사용자가 일방적으로 영상을 시청, 감상하는 소극적 영상의 소비자에서 벗어나, 기존의 영상을 이용해 임의의 영상을 조합하고 자기 자신의 영상까지 실시간으로 개입할 수 있도록 함으로써, 영상을 새롭게 구성하고 영상 재생산의 적극적 주체가 되는 사용자 중심의 새로운 영화(뉴미디어)의 토대가 될 것으로 기대된다.

  • PDF

A Study on Automatic Modeling of Pipelines Connection Using Point Cloud (포인트 클라우드를 이용한 파이프라인 연결 자동 모델링에 관한 연구)

  • Lee, Jae Won;Patil, Ashok Kumar;Holi, Pavitra;Chai, Young Ho
    • Korean Journal of Computational Design and Engineering
    • /
    • v.21 no.3
    • /
    • pp.341-352
    • /
    • 2016
  • Manual 3D pipeline modeling from LiDAR scanned point cloud data is laborious and time-consuming process. This paper presents a method to extract the pipe, elbow and branch information which is essential to the automatic modeling of the pipeline connection. The pipe geometry is estimated from the point cloud data through the Hough transform and the elbow position is calculated by the medial axis intersection for assembling the nearest pair of pipes. The branch is also created for a pair of pipe segments by estimating the virtual points on one pipe segment and checking for any feasible intersection with the other pipe's endpoint within the pre-defined range of distance. As a result of the automatic modeling, a complete 3D pipeline model is generated by connecting the extracted information of pipes, elbows and branches.

Synthesis of Realistic Facial Expression using a Nonlinear Model for Skin Color Change (비선형 피부색 변화 모델을 이용한 실감적인 표정 합성)

  • Lee Jeong-Ho;Park Hyun;Moon Young-Shik
    • Proceedings of the Korean Information Science Society Conference
    • /
    • 2006.06a
    • /
    • pp.121-123
    • /
    • 2006
  • 얼굴의 표정은 얼굴의 구성요소 같은 기하학적 정보와 조명이나 주름 같은 세부적인 정보들로 표현된다. 얼굴 표정은 기하학적 변형만으로는 실감적인 표정을 생성하기 힘들기 때문에 기하학적 변형과 더불어 텍스쳐 같은 세부적인 정보도 함께 변형해야만 실감적인 표현을 할 수 있다. 표정비율이미지 (Expression Ratio Image)같은 얼굴 텍스처의 세부적인 정보를 변형하기 위한 기존 방법들은 조명에 따른 피부색의 변화를 정확히 표현할 수 없는 단점이 있다. 따라서 본 논문에서는 이러한 문제를 해결하기 위해 서로 다른 조명 조건에서도 실감적인 표정 텍스처 정보를 적용할 수 있는 비선형 피부색 모델 기반의 표정 합성 방법을 제안한다. 제안된 방법은 동적 외양 모델을 이용한 자동적인 얼굴 특징 추출과 와핑을 통한 표정 변형 단계, 비선형 피부색 변화 모델을 이용한 표정 생성 단계, Euclidean Distance Transform (EDT)에 의해 계산된 혼합 비율을 사용한 원본 얼굴 영상과 생성된 표정의 합성 등 총 3 단계로 구성된다. 실험결과는 제안된 방법이 다양한 조명조건에서도 자연스럽고 실감적인 표정을 표현한다는 것을 보인다.

  • PDF

Estimation of Distance and Direction for Tracking of the Moving Object

  • Kang, Sung-Kwan;Park, Jong-An
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 2000.10a
    • /
    • pp.557-557
    • /
    • 2000
  • Tracking of the moving object, which is realized by the computer vision, is used for military and industrial fields. It is the application technique with imply complicated processing for understanding the input images. But, in these days, the most moving object tracking algorithms have many difficult problems. A typical problem is the increase of calculation time depending on target number. For this reason, there are many studies to solve real time processing problems and errors for background environmental change. In this paper, we used optical flow which is one of moving object tracking algorithms. It represents vector of the moving object. Optical flow estimation based on the regularization method depends on iteration method but it is very sensitive the noise. We proposed a new method using the Combinatorial Hough Transform (CHT) and Voting Accumulation in order to find optimal constraint lines. Also, we used the logical operation in order to release the operation time. The proposed method can easily and accurately extract the optical flow of moving object area and the moving information. We have simulated the proposed method using the test images. This images are included the noise. Experimental results show that the proposed method get better flow and estimate accurately the moving information.

  • PDF

Recognition of Passport MRZ Information Using Combined Neural Networks (결합 신경망을 이용한 여권 MRZ 정보 인식)

  • Kim, Jinho
    • Journal of Korea Society of Digital Industry and Information Management
    • /
    • v.15 no.4
    • /
    • pp.149-157
    • /
    • 2019
  • In case of reading passport using a smart phone in contrast with a dedicated passport reading system, MRZ(Machine Readable Zone) character recognition can be hard when the character strokes were broken, touched or blurred according to the lighting condition, and the position and size of MRZ character lines were varied due to the camera distance and angle. In this paper, the effective recognition algorithm of the passport MRZ information using a combined neural network recognizer of CNN(Convolutional Neural Network) and ANN( Artificial Neural Network), is proposed under the various sized and skewed passport images. The MRZ line detection using connected component analysis algorithm and the skew correction using perspective transform algorithm are also designed in order to achieve effective character segmentation results. Each of the MRZ field recognition results is verified by using five check digits for deciding whether retrying the recognition process of passport MRZ information or not. After we implement the proposed recognition algorithm of passport MRZ information, the excellent recognition performance of the passport MRZ information was obtained in the experimental results for PC off-line mode and smart phone on-line mode.

Face Recognition Method using Geometric Feature and PCA/LDA in Wavelet Domain (웨이브릿 영역에서 기하학적 특징과 PCA/LDA를 사용한 얼굴 인식 방법)

  • 송영준;김영길
    • The Journal of the Korea Contents Association
    • /
    • v.4 no.3
    • /
    • pp.107-113
    • /
    • 2004
  • This paper improved the performance of the face recognition system using the PCA/LDA hybrid method based on the facial geometric feature and the Wavelet transform. Because the previous PCA/LDA methods have measured the similarity according to the formal dispersion, they could not reflect facial boundaries exactly In order to recover this defect, this paper proposed the method using the distance between eyes and mouth. If the difference of the measured distances on the query and the training images is over the given threshold, then the method reorders the candidate images according to energy feature vectors of eyes, a nose, and a chin. To evaluate the performance of the proposed method the computer simulations have been performed with four hundred facial images in the ORL database. The results showed that our method improves about 4% recognition rate over the previous PCA/LDA method.

  • PDF

Tiny and Blurred Face Alignment for Long Distance Face Recognition

  • Ban, Kyu-Dae;Lee, Jae-Yeon;Kim, Do-Hyung;Kim, Jae-Hong;Chung, Yun-Koo
    • ETRI Journal
    • /
    • v.33 no.2
    • /
    • pp.251-258
    • /
    • 2011
  • Applying face alignment after face detection exerts a heavy influence on face recognition. Many researchers have recently investigated face alignment using databases collected from images taken at close distances and with low magnification. However, in the cases of home-service robots, captured images generally are of low resolution and low quality. Therefore, previous face alignment research, such as eye detection, is not appropriate for robot environments. The main purpose of this paper is to provide a new and effective approach in the alignment of small and blurred faces. We propose a face alignment method using the confidence value of Real-AdaBoost with a modified census transform feature. We also evaluate the face recognition system to compare the proposed face alignment module with those of other systems. Experimental results show that the proposed method has a high recognition rate, higher than face alignment methods using a manually-marked eye position.

An Algorithm for Discontinuous Surface Profile Measurement using Wavelength Scanning Interferometer (파장 주사 간섭계를 이용한 불연속면의 표면 형상 측정 알고리즘)

  • 우현구;강철무;조형석
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.9 no.7
    • /
    • pp.507-514
    • /
    • 2003
  • Inspection and shape measurement of three-dimensional objects are widely needed in industries for quality monitoring and control. Recently the shape measurement using interferometric principle is found to be a successful methodology among other visual or optical technologies. Especially, the measuring method using wavelength scanning interferometer(WSI) has a great advantage in comparison with other conventional jnterferometric methods in that the absolute distance from the reference surface can be directly obtained from the amount of jnterferometric phase change. However, the measurement methods using WSI proposed by other researchers have low measurement resolution so far because they can't measure fractional phase change. To avoid this shortcoming we propose a new algorithm in this paper, which can obtain a small amount of even fractional phase change by sinusoidal function fitting. To evaluate the effectiveness of the proposed sinusoidal function fitting algorithm, a series of measuring experiments are conducted for discontinuously shaped specimens which have various height. The proposed algorithm shows much more enhanced measurement resolution than other existing conventional algorithms such as zero crossing algorithm and Fourier transform algorithm.