• Title, Summary, Keyword: Optical correlator

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A Study of Car Plate Recognition System on The Park (주차장 자동차번호 인식 시스템에 관한 연구)

  • 신강호
    • Journal of the Korea Society of Computer and Information
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    • v.8 no.4
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    • pp.87-91
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    • 2003
  • In this paper, a rotation invariant fingerprint identification system is implemented using the circular harmonic filter and phase only correlator. We extracted the phase component from input fingerprint image and correlate it with the circular harmonic filter of the reference fingerprint image by POC. The input image is obtained using a prism operating in the internal full reflection mode. Then the input image is transformed to two dimensional Fourier spectrum in optical way and the phase component is extracted using a digital system from the spectrum. Because composed of the optical system and digital algorithm, the proposed system has the advantages of the two technologies such as realtime parallel processing property of the optics and the flexibility of the digital system.

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A Study on The Rotation Invariant Fingerprint Identification Using a Circular Harmonic Filter (순환 고조파 필터를 이용한 회전불변 지문 인식에 관한 연구)

  • 신강호;채호병;정연만
    • Journal of the Korea Society of Computer and Information
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    • v.8 no.3
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    • pp.94-99
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    • 2003
  • In this paper, a rotation invariant fingerprint identification system is implemented using the circular harmonic filter and phase only correlator. We extracted the phase component from input fingerprint image and correlate it with the circular harmonic filter of the reference fingerprint image by POC. The input image is obtained using a prism operating in the internal full reflection mode. Then the input image is transformed to two dimensional Fourier spectrum in optical way and the phase component is extracted using a digital system from the spectrum. Because composed of the optical system and digital algorithm, the proposed system has the advantages of the two technologies such as realtime parallel processing property of the optics and the flexibility of the digital system.

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Off-axis pSDF Spatial Matched Filter for Pattern Classification (패턴분류를 위한 Off-axis pSDF 공간정합필터)

  • 임종태;박한규;김명수;김성일
    • Korean Journal of Optics and Photonics
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    • v.2 no.2
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    • pp.83-88
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    • 1991
  • Studies on space-invariant pattern recognition have been carried out from various approaches. Pattern recognition system using SDF filter, from weighted linear summation of tranining images, has been the focus of research since its first appearence. In this thesis, off-axis pSDF spatial matched filter has been constructed by combining angular multiplexing of off-axis reference plane wave with pSDF filter made from pseudo-inverse algorithm, and transformed to phase only filter. From observation of the correlation responses in the correlation plane, it is shown that proposed off-axis pSDF spatial matched filter is available to pattern classification and can be used for optical correlator.

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Distortion-Invariant Korean Character Recognition With Parallel Tree Structure Using MACE Concept (MACE 개념을 이용한 병렬 나무 구조로부터의 왜곡에 무관한 한글문자 인식)

  • Yu, Wee-Kyung;Kim, Jeong-Woo;Doh, Yang-Hoi;Kim, Soo-Joong
    • Annual Conference on Human and Language Technology
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    • pp.148-153
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    • 1989
  • 본 논문에서는 광 상관기 (optical correlator) 에 의한 한글문자 분리 인식의 한 방법을 제안하였다. 효율적인 분리 인식을 위해서 병렬 나무 (tree) 구조로부터 입력 신호를 두 방향으로 병렬 처리하여 각 방향으로 자음과 모음을 따로 분리시켜 2단계 만에 인식한 뒤 이들을 위치에 따라 조합하여 문자 분리 인식하도록 하며, 아울러 이러한 병렬 나무구조의 각 단계에서 필터 합성시 MACE (minimum average correlation energy) 개념을 이용하여 광 상 관평면상에서 부엽의 문제를 줄이고, 실제 광 시스템에서 생길 수 있는 왜곡을 학습표본에 포함하여 광 상관기 시스템에 의한 실질적인 한글 문자의 왜곡에 무관한 분리인식을 하도록 하였다.

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hardware implementation of multi-target tracking system based on binary phase extraction JTC (BPEJTC를 이용한 다중표적 추적시스템의 하드웨어 구현)

  • 이승현;이상이;류충상;차광훈;서춘원;김은수
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.10
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    • pp.152-159
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    • 1996
  • We have designed and implemented an optoelectronic hardware of binary phase extraction joint transform correlator (BPEJTC) which provides higher peak-to-sidelobe ratio than many other versions of JTC that has been published so far and does not produce correlation peaks due to intra-class association, to construct a multi-target tracking system. The digital processing unit controlling the entire system plays the part of modifying and binarizing the joint transform power spectrum (JTPS) and the optical processing unit is mainly used to take fourier transform operations. Some experimental results conducted by designed system along with its architecture showed the processing rate of 6 frames per second, thereby the potential applicability of the proposed system to real-time multitarget tracking system is given.

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Opto-Digital Implementation of Convergence-Controlled Stereo Target Tracking System (주시각이 제어된 스테레오 물체추적 시스템의 광-디지털적 구현)

  • 고정환;이재수;김은수
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.4B
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    • pp.353-364
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    • 2002
  • In this paper, a new onto-digital stereo object-tracking system using hierarchical digital algorithms and optical BPEJTC is proposed. This proposed system can adaptively track a moving target by controlling the convergence of stereo camera. firstly, the target is detected through the background matching of the sequential input images by using optical BPEJTC and then the target area is segmented by using the target projection mask which is composed by hierarchical digital processing of image subtraction, logical operation and morphological filtering. Secondly, the location's coordinate of the moving target object for each of the sequential input frames can be extracted through carrying out optical BPEJTC between the reference image of the target region mask and the stereo input image. Finally, the convergence and pan/tilt of stereo camera can be sequentially controlled by using these target coordinate values and the target can be kept in tracking. Also, a possibility of real-time implementation of the adaptive stereo object tracking system is suggested through optically implementing the proposed target extraction and convergence control algorithms.

Image Recognition of JTC by Using Fresnel Computer Generated Hologram (프레넬 컴퓨터 홀로그램을 이용한 결합광상관기의 영상 인식)

  • Jeong, Man-Ho
    • The Journal of Korean Institute of Information Technology
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    • v.15 no.8
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    • pp.101-106
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    • 2017
  • We present a new technique of face recognition capability of the JTC by using the computer generated holograms(CGH) of the 3-D face images instead of using those original images. This method of using the CGH of the 3-D face images for the pattern recognition have advantages such as security and counterfeit problems compared with the conventional method of using those original images. This technique calculates Fresnel diffraction pattern of the 3-D face images by using computer program to obtain Fresnel CGH of those images, then recognize the face images using the JTC. This paper presents some data of correlation peaks and SNR, representing 2.6 and 2.4 respectively, shows the discrimination capability of this new method.

A simple Demonstration of the Wiener-Khinchin Theorem using a Digital Oscilloscope and Personal Computer (디지털 오실로스코프에 의한 Wiener-Khinchin 정리의 시현)

  • Jung, Se-Min
    • Korean Journal of Optics and Photonics
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    • v.24 no.5
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    • pp.245-250
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    • 2013
  • The Wiener-Khinchin theorem, which means that the autocorrelation function of a signal corresponds to the power spectrum of the signal, is very important in signal processing, spectroscopy and telecommunications engineering. However, because of needs for some relatively expensive equipments such as a correlator and the signal processing system, its demonstration in most undergraduate class is not easy so far. Recently, digital oscilloscopes whose functions can be replaced foresaid equipments are marketed with development of digital engineering. In this paper, a simple demonstration of the theorem is given by a digital storage oscilloscope and a personal computer with its theoretical background. The reason that deals again with this theorem which has been introduced in 1930 is that it has been not well informed yet to us and theoretical background of the demonstration is directly introduced from its driving process. Through deriving process of the theorem, some extended physical meanings of the impedance, power, power factor, Wiener spectrum, linear system response and, furthermore, basic idea of the Planck's quantization in the black body theory reveal themselves naturally. Hence it can be referred to lectures in general physics, modern physics, spectroscopy and material characterization experiment.

Image Encryption and Decryption System using Frequency Phase Encoding and Phase Wrapping Method (주파수 위상 부호화와 위상 랩핑 방법을 이용한 영상 암호화 및 복호화 시스템)

  • Seo, Dong-Hoan;Shin, Chang-Mok;Cho, Kyu-Bo
    • Korean Journal of Optics and Photonics
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    • v.17 no.6
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    • pp.507-513
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    • 2006
  • In this paper, we propose an improved image encryption and fault-tolerance decryption method using phase wrapping and phase encoding in the frequency domain. To generate an encrypted image, an encrypting key which denotes the product of a phase-encoded virtual image, not an original image, and a random phase image is zero-padded and Fourier transformed and its real-valued data is phase-encoded. The decryption process is simply performed by performing the inverse Fourier transform for multiplication of the encrypted key with the decrypting key, made of the proposed phase wrapping method, in the output plane with a spatial filter. This process has the advantages of solving optical alignment and pixel-to-pixel mapping problems. The proposed method using the virtual image, which does not contain any information from the original image, prevents the possibility of counterfeiting from unauthorized people and also can be used as a current spatial light modulator technology by phase encoding of the real-valued data. Computer simulations show the validity of the encryption scheme and the robustness to noise of the encrypted key or the decryption key in the proposed technique.

Design of a Bit-Serial Divider in GF(2$^{m}$ ) for Elliptic Curve Cryptosystem (타원곡선 암호시스템을 위한 GF(2$^{m}$ )상의 비트-시리얼 나눗셈기 설계)

  • 김창훈;홍춘표;김남식;권순학
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.27 no.12C
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    • pp.1288-1298
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    • 2002
  • To implement elliptic curve cryptosystem in GF(2$\^$m/) at high speed, a fast divider is required. Although bit-parallel architecture is well suited for high speed division operations, elliptic curve cryptosystem requires large m(at least 163) to support a sufficient security. In other words, since the bit-parallel architecture has an area complexity of 0(m$\^$m/), it is not suited for this application. In this paper, we propose a new serial-in serial-out systolic array for computing division operations in GF(2$\^$m/) using the standard basis representation. Based on a modified version of tile binary extended greatest common divisor algorithm, we obtain a new data dependence graph and design an efficient bit-serial systolic divider. The proposed divider has 0(m) time complexity and 0(m) area complexity. If input data come in continuously, the proposed divider can produce division results at a rate of one per m clock cycles, after an initial delay of 5m-2 cycles. Analysis shows that the proposed divider provides a significant reduction in both chip area and computational delay time compared to previously proposed systolic dividers with the same I/O format. Since the proposed divider can perform division operations at high speed with the reduced chip area, it is well suited for division circuit of elliptic curve cryptosystem. Furthermore, since the proposed architecture does not restrict the choice of irreducible polynomial, and has a unidirectional data flow and regularity, it provides a high flexibility and scalability with respect to the field size m.