Published Papers - NOMURA Takanori

Frequency domain methods in digital photoelasticity

Y Morimoto, T Nomura, M Fujigaki, R Matsui

SECOND INTERNATIONAL CONFERENCE ON EXPERIMENTAL MECHANICS ( SPIE-INT SOC OPTICAL ENGINEERING )  4317   117 - 122   2001  [Refereed]

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To analyze fringe patterns, frequency and phase analysis of fringes becomes popular. It provides accurate results and automated processing. In this paper, the theories of the frequency and phase domain methods such as the Fourier transform method, the wavelet transform method and the phase-shifting method are proposed for photoelastic fringe pattern analysis. The applications of these methods are described.

Digital holographic data reconstruction with data compression

T Nomura, A Okazaki, M Kameda, Y Morimoto, B Javidi

ALGORITHMS AND SYSTEMS FOR OPTICAL INFORMATION PROCESSING V ( SPIE-INT SOC OPTICAL ENGINEERING )    235 - 242   2001  [Refereed]

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A digital holographic data reconstruction method with data compression is proposed. We show the number of quantization level of a digital hologram can be reduced. By computer simulations it is confirmed that the method is especially useful for binary images. For gray scale images, we propose a bit plane decomposition method. By this method, we show both high reconstructed image quality and a high compression ratio can be achieved. This method is applicable to both a normal digital hologram and an encrypted digital hologram.

Three-dimensional prediction for lossless coding of digital RGB image

Nobutaka Kuroki, Takanori Nomura, Masashi Kameda, Masahiro Numa, Kotaro Hirano

Memoirs of the Faculty of Engineering, Kobe University   46   69 - 79   1999

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A three-dimensional (3-D) linear prediction method for lossless coding of RGB images is proposed. In this method, an RGB signal is divided into three components and piled up as a 3-D signal. In order to remove redundancy among these components, a signal value is predicted from its neighboring points and transformed into an error signal. The prediction value is given by a linear combinaion of the neighboring points. Coefficients for those points are calculated with the least square method. Since the proposed method employs hybrid prediction including 2-D prediction and inter-component prediction, it can remove both the redundancy among adjecent pixels and that among three components at the same time. In this paper, several static or dynamic prediction methods are performed and entropies of the error signals are discussed. On an average for nine test images, the entropy of error signal generated by the proposed method is 7% smaller than that by inter-component prediction.

Hartley transformation for hybrid pattern matching

Takanori Nomura, Kazuyoshi Itoh, Yoshiki Ichioka

Applied Optics   29 ( 29 ) 4345 - 4350   1990.10  [Refereed]

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A hybrid pattern matching system using the binary versions of the Hartley and related transformations is presented. These transformations can be obtained by an incoherent optical system described in this paper. *Using them, the spurious correlation signals inherent in an incoherent pattern matching system based on the optical cosine transformation are removed. Experimental demonstrations in an incoherent-optical/digital- electronic hybrid system are also presented. © 1990 Optical Society of America.

DOI

Hybrid high speed pattern matching using a binary incoherent hologram generated by a rotational shearing interferometer

T. Nomura, K. Itoh, Y. Ichioka

Applied Optics   28 ( 23 ) 4987 - 4991   1989  [Refereed]

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A hybrid image processing system for high speed pattern matching is presented. The system consists of an incoherent optical system and an electronic digital image processor. The optical system makes use of the matched filtering technique based on incoherent holography. The incoherent holograms of an input object and a reference object are binarized. This binarization of holograms has two major advantages: (1) it sharpens the autocorrelation peak, and (2) it makes real time processing possible. We demonstrate the high potential of this method by presenting computer simulations and experiments. © 1989, Optical Society of America.

DOI