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Author

Shoichiro Yamaguchi

Bio: Shoichiro Yamaguchi is an academic researcher from Tokyo Institute of Technology. The author has contributed to research in topics: Layer (electronics) & Grating. The author has an hindex of 9, co-authored 84 publications receiving 513 citations.


Papers
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Journal ArticleDOI
TL;DR: In this correspondence, a structural recognition method of Arabic cursively handwritten words is proposed, in which words are first segmented into strokes and classified using their geometrical and topological properties.
Abstract: In spite of the progress of machine recognition techniques of Latin, Kana, and Chinese characters over the two past decades, the machine recognition of Arabic characters has remained almost untouched. In this correspondence, a structural recognition method of Arabic cursively handwritten words is proposed. In this method, words are first segmented into strokes. Those strokes are then classified using their geometrical and topological properties. Finally, the relative position of the classified strokes are examined, and the strokes are combined in several steps into a string of characters that represents the recognized word. Experimental results on texts handwritten by two persons showed high recognition accuracy.

209 citations

Patent
02 Mar 2007
TL;DR: In this article, a piezoelectric thin film filter including four film bulk acoustic resonators has a configuration where a filter section and a base substrate are bonded to each other via an adhesive layer.
Abstract: The present invention is directed to improving characteristics of a piezoelectric thin film device. A piezoelectric thin film filter including four film bulk acoustic resonators has a configuration where a filter section and a base substrate are bonded to each other via an adhesive layer, the filter section including a piezoelectric thin film which cannot stand up individually under its own weight, the flat base substrate mechanically supporting the filter section. As a piezoelectric material constructing the piezoelectric thin film, it is desirable to use a single-crystal material including no grain boundary, selected from crystal, lithium niobate, lithium tantalite, lithium tetraborate, zinc oxide, potassium niobate, and langasite.

59 citations

Patent
11 Oct 2005
TL;DR: In this paper, a ridge-type optical waveguide is proposed to reduce the loss to be incurred when an incident light propagates through a 3D optical waveguide substrate.
Abstract: An optical waveguide substrate having a ridge type optical waveguide, wherein a structure capable of reducing loss to be incurred when an incident light propagates through a three-dimensional optical waveguide is provided. The optical wavegide substrate comprises a ferroelectric layer (3) consisting of a ferroelectric material, a ridge unit formed on the surface of the ferroelectric layer (3), protrusions respectively provided on the opposite sides of the ridge unit, and a three-dimensional optical waveguide provided on the ridge unit. Alternatively, the substrate comprises a ridge unit (15) formed on the surface of the ferroelectric layer (3), step differences (25A, 25B) respectively provided on the opposite sides of the ridge unit (15) and being lower than the ridge unit (15), grooves (16) respectively formed on the outer sides of respective step differences, and a three-dimensional optical waveguide provided on the ridge unit (15).

25 citations

Patent
06 Mar 2007
TL;DR: In this paper, a wavelength converting device comprising a periodic domain inversion structure for converting a wavelength of a fundamental wave to generate a harmonic wave is provided, where the wavelength conversion device includes a ferroelectric substrate.
Abstract: It is provided a wavelength converting device comprising a periodic domain inversion structure for converting a wavelength of a fundamental wave to generate a harmonic wave. The wavelength conversion device includes a ferroelectric substrate and the periodic domain inversion structure formed in the ferroelectric substrate. A vertical domain inversion boundary of the periodic domain inversion structure is inclined with respect to a normal line of an upper face of the ferroelectric substrate, provided that the ferroelectric substrate is viewed in a cross section parallel with a propagating direction of the fundamental wave and parallel with the normal line of the upper face.

24 citations

Patent
12 Nov 1980
TL;DR: In this article, a tomographic image of a X-ray tested tissue of body is reconstructed by calculating the absorption coefficients of picture elements constituting the tomographic plane in reference to the measured values produced by the first and second projectional distributions of Xray produced by projecting X-rays.
Abstract: A tomographic image of a X-ray tested tissue of body is reconstructed by calculating X-ray absorption coefficients of picture elements constituting a tomographic plane in reference to measured values produced by the first and second projectional distributions of X-ray produced by projecting X-ray. Accordingly, it becomes possible to reconstruct a clear tomographic image of a moving X-ray tested tissue and to make an X-ray exposure level very low by extremely shortening the time of the reconstruction of computed tomographic image. Moreover, a resolving power of measuring is substantially improved, resulting in that an accuracy of reconstructing the tomographic image may also be improved.

17 citations


Cited by
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Journal ArticleDOI
TL;DR: There still is a great gap between human reading and machine reading capabilities, and a great amount of further effort is required to narrow-down this gap, if not bridge it.

508 citations

Journal ArticleDOI
TL;DR: This paper is the first survey to focus on Arabic handwriting recognition and the first Arabic character recognition survey to provide recognition rates and descriptions of test data for the approaches discussed.
Abstract: The automatic recognition of text on scanned images has enabled many applications such as searching for words in large volumes of documents, automatic sorting of postal mail, and convenient editing of previously printed documents. The domain of handwriting in the Arabic script presents unique technical challenges and has been addressed more recently than other domains. Many different methods have been proposed and applied to various types of images. This paper provides a comprehensive review of these methods. It is the first survey to focus on Arabic handwriting recognition and the first Arabic character recognition survey to provide recognition rates and descriptions of test data for the approaches discussed. It includes background on the field, discussion of the methods, and future research directions.

503 citations

Journal ArticleDOI
TL;DR: By performing real-time measurements of the time durations between the keystrokes when a password is entered and using pattern-recognition algorithms, three online recognition systems were devised and tested.
Abstract: An approach to securing access to computer systems is described. By performing real-time measurements of the time durations between the keystrokes when a password is entered and using pattern-recognition algorithms, three online recognition systems were devised and tested. Two types of passwords were considered: phrases and individual names. A fixed phrase was used in the identification system. Individual names were used as a password in the verification system and in the overall recognition system. All three systems were tested and evaluated. The identification system used 10 volunteers and gave an indecision error of 1.2%. The verification system used 26 volunteers and gave an error of 8.1% in rejecting valid users and an error of 2.8% in accepting invalid users. The overall recognition system used 32 volunteers and gave an error of 3.1% in rejecting valid users and an error of 0.5% in accepting invalid users. >

328 citations

Journal ArticleDOI
TL;DR: In this article, the authors present the state of Arabic character recognition research throughout the last two decades and present the main objective of this paper is to present the current state of the research.

319 citations

Journal ArticleDOI
TL;DR: This paper introduces the general topic of optical character recognition (OCR), and introduces a five stage model for AOTR systems and classify research work according to this model, and presents an historical review of the Arabic text recognition systems.

260 citations