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Showing papers by "Nagaaki Ohyama published in 1987"


Journal ArticleDOI
TL;DR: In this article, a multiplex hologram is sythesized from a series of CT (computer-aided tomogram) sectional images of the head of a patient taken with a small interval along the body axis.

25 citations


Journal ArticleDOI
TL;DR: A discrete Radon transform in a continuous space is discussed in order to establish an analytically exact method to synthesize projections from discretely sampled data.
Abstract: We discuss a discrete Radon transform in a continuous space in order to establish an analytically exact method to synthesize projections from discretely sampled data. The method shown is based on sampling theory and assumes that an object is band limited. Comparisons with conventional projection methods, namely, linear interpolation and pixel projection, are shown together with a computer simulation.

20 citations


Journal ArticleDOI
TL;DR: A digital method is proposed for the restoration of images color-shifted by the object motion that makes use of phase-only matching followed by a resampling operation to compensate for a space-variant shift between different primary color images.
Abstract: Color CCD endoscopes with sequential three-color illuminations have the advantage of high spatial resolution but are sensitive to object motion. A digital method is proposed for the restoration of images color-shifted by the object motion. The method makes use of phase-only matching followed by a resampling operation to compensate for a space-variant shift between different primary color images. Restored images are suitable for further image processing such as color emphasis and structure enhancement.

9 citations


Proceedings ArticleDOI
01 Jan 1987
TL;DR: This work proposes to find an optimal generalized color plane in which to carry out the correlation operation and considers the retrieval of the mucosal surface structure from stereo pairs taken through an endoscope with maximization of the peak-to-deviation ratio in the correlation plane.
Abstract: Despite evidences from human vision research (1) that spatial and color characteristics of images are strongly related, the use of color for recognition purposes has received little attention. However,in the framework of the development of increasingly versatile machine vision systems, the introduction of the color feature seems to be a rather natural step. A color approach is obviously not always possible and justified and therefore we are interested in cases where color images are at hand and where recognition accuracy is more important than processing speed. In this work we extend the concepts introduced earlier (2) andpropose to find an optimal generalized color plane in which to carry out the correlation operation. The optimality is defined in terms of the maximization of the peak-to-deviation ratio in the correlation plane. As an application we consider the retrieval of the mucosal surface structure from stereo pairs taken through an endoscope.

2 citations


Journal ArticleDOI
TL;DR: In this article, the authors discuss systematic errors of the dynamic zone-plate interferometer caused by the inaccuracy of optical system parameters such as the focal length of the zone plate, the distance between the zoneplate and the mirror under test, and the wavelengths of the source.

2 citations


Journal ArticleDOI
TL;DR: An optical filtering system with a white light illumination is shown to be very effective for the preprocessing of endoscopic color images and experimental results show the advantage of an optical system against a digital method.

1 citations


Journal ArticleDOI
TL;DR: A new technique calculating the deviation in the color plane is proposed, which has a shorter operation time and an effective usefulness.