• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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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.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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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.

• Journal of the Optical Society of Korea
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• 제14권4호
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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.

• Journal of the Optical Society of Korea
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• 제14권2호
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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.

• Journal of the Optical Society of Korea
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• 제18권5호
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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.

• 전자공학회논문지A
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• 제31A권6호
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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.

• 전자공학회논문지S
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• 제34S권2호
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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.

• Journal of the Optical Society of Korea
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• 제14권1호
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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.

• 한국광학회지
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• 제14권5호
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• pp.491-497
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• 2003

Joint transform correlator(JTC)를 기반으로 이진 암호화 키를 사용하는 광 암호화 시스템을 제시하였다. 이진 암호화 키는 Pixel-oriented CGH의 설계방법을 이용하여 제작하였고, 컴퓨터 모의 실험결과를 통하여 구현된 이진 암호화 키의 독립성 및 효능을 조사하였다. CGH방법으로 구현된 이진 암호화 키의 효능을 검증하기 위하여 홀로그래픽 메모리 기반의 광 암호화 장치를 구성하여 실험을 하였으며 그 결과 높은 암호화 가능성을 나타내었다.

• Journal of the Optical Society of Korea
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• 제15권4호
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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.