• Title/Summary/Keyword: Joint transform correlator

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Effects of JPEG Compression on Joint Transform Correlator

  • Widjaja, Joewono;Suripon, Ubon
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.1662-1665
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    • 2004
  • A real-time joint transform correlator by using JPEG-compressed reference images is proposed as practical solution to storage problem and improvement of processing time of automatic target recognition system [1]. Effects of compression on recognition performance of join transform correlator are quantitatively investigated under situations where the target is suffered from noise and has contrast difference with respect to the reference. Two images with different spatial-frequency contents and contrast were used as the test scenes. The simulation results show that, the recognition performance of joint transform correlator by using the compressed reference images with high spatial-frequency components is more sensitive to noise and contrast difference than the low spatial-frequency image.

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Fourier-Plane Encryption System using Divided Images and a Joint Transform Correlator (분할 영상과 결합변환 상관기를 이용한 주파수 영역에서의 광 암호화 시스템 구현)

  • 최상규;신창목;서동환;김수중;배장근
    • Proceedings of the Optical Society of Korea Conference
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    • 2003.02a
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    • pp.58-59
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    • 2003
  • We propose the optical encryption system using two divided image to hide the original image and a joint transform correlator. The encryption procedure is performed by the Fourier transform of the product of each phase encoded image (divided phase images) and the same random phase image which is generated by computer processing. An autocorrelation term of joint transform correlator contributes to decrypt the original image. This system will be used in optical certification.

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Binary Nonlinear Joint Transform Correlator with Sinusoidal Iterative Filter in Spectrum Domain

  • Jeong, Man-Ho
    • Journal of the Optical Society of Korea
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    • v.14 no.4
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    • pp.357-362
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    • 2010
  • The joint transform correlator (JTC) has been the best known technique for pattern recognition and identification. This paper proposes a new technique of fringe adjustment by adopting a sinusoidal amplitude-modulated iterative filter convolved with an interference fringe pattern in the joint power spectrum (JPS) domain. The comparison of our new technique and other techniques is presented to show that the newly proposed technique can successfully improve both the correlation peaks and the peak signal-to-noise ratio (PSNR). Simulated results of enhanced interference fringes are also presented.

New Random and Additional Phase Adjustment of Joint Transform Correlator

  • Jeong, Man-Ho
    • Journal of the Optical Society of Korea
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    • v.14 no.2
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    • pp.90-96
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    • 2010
  • Joint transform correlator (JTC) has been the most suitable technique for real time pattern recognition. This paper proposes a new phase adjustment which adopts two steps of random phase adjustment in the spatial domain and additional phase adjustment in the Fourier domain. Simulated results are presented to show the optimum condition of the phase adjustment and the effect on the correlation peaks, the peak signal-to-noise ratio and the level of discrimination.

Image Blurring Estimation and Calibration with a Joint Transform Correlator

  • Jeong, Man Ho
    • Journal of the Optical Society of Korea
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    • v.18 no.5
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    • pp.472-476
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    • 2014
  • The Joint Transform Correlator (JTC) has been the most suitable technique for real time optical pattern recognition and target tracking applications. This paper proposes a new application of the JTC system for an analysis of the blurring effect of the optical images caused by a defocused lens. We present the relation between the correlation peak, optical transfer function (OTF), and the amount of blurring caused by focusing error. Moreover, we show a possibility of calibrating the blurred image by simply measuring the correlation peak.

Optical Binary Phase Extraction Joint Transform Correlator System for Improving the Correlation Discrimination (상관신호의 판별력 개선을 위한 광 BPEFTC 시스템)

  • 이상이;김은수
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.6
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    • pp.78-87
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    • 1994
  • In this paper, a binary phase extraction joiont transform correlator (BPEJTC)system is proposed as a new phase-type optical correlator in which the correlation errors and DC component are dramtically reduced and optical efficiency and correlation performance are also improved by reconstructing the joint transform power spectrum (JTPS) of the conventional joint transform correlator (JTC)system form which the autocorrelation and crosscorrelation siganls generated in each self-plane are removed, and the binary phase function is extracted from the phase value of the reconstructed JTPS. Through some computer simulation and optical experimental results, the possibility of the implementation of the real-time multi-target tracking and recognition system is also suggested.

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Wavelet circular harmonic function frequency selective joint transform correlator for rotation invariant pattern recognition (회전불변 패턴인식을 위한 WCHF-FSJTC)

  • 방준학;이하운;노덕수;김수중
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.2
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    • pp.94-103
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    • 1997
  • The WCHF-FSJTC (wavelet circular harmonic function frequency selective joint transform correlator) using th wavelet transformed CHF as the reference image in FSJTC is proposed for rotation invariant pattern recognition. Since the wavelet transform has the property of feature extraction, the proposed system can have the better DC (discrimination cpability) and the higher SNR(signal to noise ratio) compared with the conventional CHF-CJTC(circular harmonic function conventional joint transform correlator). And since the structure of the proposed system is FSJTC which can eliminate auto-correlation and cross-correlation between input images, it can eliminate false alarm caused by the overlapping among correlation peaks. The used wavelet functio is the morlet function, which is proper for the reference image used in this paper. the optimal dialation parameter and oscillation frequency of the wavelet function are also achieved with varying the parameters of the wavelet function. The computer simulation shows that the proposed system has the best performance when the dilation parameter is 0.8 and the oscillation frequency is 0.48.

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New Iterative Filter for Fringe Adjustment of Joint Transform Correlator

  • Jeong, Man-Ho
    • Journal of the Optical Society of Korea
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    • v.14 no.1
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    • pp.33-37
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    • 2010
  • The joint transform correlator (JTC) has been the best known technique for pattern recognition and identification. The JTC optically compares the reference image with the sample image then examines match or non-match by acquiring a correlation peak. However, the JTC technique has some problems such as weak correlation discrimination and noise which originates from the interference fringes in the Fourier transform plane. In order to solve these problems, this paper proposes a new technique of modifications of the interference fringes by adopting special iterative filters. Experimental results are presented to show that the proposed technique can successfully improve the correlation peaks and the level of discrimination.

A study on JTC optical encryption system using binary CGHs (Binary CGH를 사용한 JTC 광암호화 시스템 연구)

  • 주성현;정만호
    • Korean Journal of Optics and Photonics
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    • v.14 no.5
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    • pp.491-497
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    • 2003
  • In this paper, an optical encryption system using binary key code based on the joint transform correlator (JTC) is considered. The binary key code is synthesized by using a design technique of the pixel-oriented Computer Generated Holograms (CGHs). The independence and efficiency of the binary encryption key are investigated through computer simulation. To test the efficiency of the encryption system using binary key code, a holographic encryption system is constructed, and the experimental results prove that our holographic encryption system has high ability.

Coded Single Input Channel for Color Pattern Recognition in Joint Transform Correlator

  • Jeong, Man-Ho
    • Journal of the Optical Society of Korea
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    • v.15 no.4
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    • pp.335-339
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    • 2011
  • Recently, we reported a single input channel joint transform correlator for the color pattern recognition which decomposes the input color image into three R, G, and B gray components and adds those components into a single gray image in the input plane. This technique has the merit of a single input channel instead of three input channels. However, we found this technique has some problems with discrimination impossibility in the case of a simple primary color pattern which results in the same gray level through the addition process. Thus, we propose a modified coding technique which selectively recombines the decomposed three R, G, and B gray components instead of the simple adding process. Simulated results show that the modified coding technique can accurately discriminate a variety of kinds of color images.