Hiroyuki Kamei

Geophysical survey of Hirui‐Otsuka Mounded Tomb in Ogaki, Japan

The Hirui-Otsuka mounded tomb located in the city of Ogaki, Gifu Prefecture, Japan, is one of the largest keyhole-shaped mounded tombs in the Tokai region. Archaeological investigations of this tomb have been carried out continuously since 1994. Some of the geophysical methods were adopted in this investigation on the basis of a remarkable concept of ‘sensor fusion’. In this paper, the results of the geophysical surveys are presented. Ground-penetrating radar (GPR) survey and resistivity survey were applied in order to find the missing moat and to determine the boundary of this tomb. The GPR time-slices have shown clearly the outline of the missing moat and this was consistent with the excavation results. However, the apparent resistivity map has shown a different result. Radar and magnetic surveys were carried out on top of the mound in order to acquire information about the tombs central burial. In this investigation, a newly developed frequency modulated continuous wave (FMCW) radar was used as well as a conventional pulse radar system. The magnetic survey was undertaken using a three-component fluxgate gradiometer. The GPR survey on top of the circular part of the mound revealed a 10 m by 10 m rectangular burial pit in the middle of which was a pit-style stone chamber about 6 m long by 2 m wide. The geomagnetic survey produced no archaeological information owing to the presence of numerous strongly magnetized obstacles near the surface of the area surveyed. Copyright

Extended photometric stereo for an object with unknown reflectance property

Conventional Photometric Stereo can obtain the surface gradients of an object when its reflectance property is known. This paper proposes a new method of accurately obtaining the surface gradients with three light source directions under the assumption that the reflectance property of the surface is unknown. Assuming that the reflectance property is uniform over the entire surface, surface gradients can be obtained by the following two steps: (1) reflectance property parameters and the gradients of the suitable surface elements that characterize the reflectance property by solving the nonlinear simultaneous equations for them, so that a pseudo-reflectance map is obtained; and (2) the gradient of each surface element is determined by using parameters obtained by (1). The reliability for the values of the reflectance property parameters (i. e., those for the pseudo-reflectance map) can be improved by applying the method of selecting the surface elements that are sensitive to the reflectance property; this is called the characterized surface elements selection method. In computer experiment with 8-bits shading resolution using three parallel light sources, the values of the reflectance property parameters can be obtained in optimum, and the accurate surface gradients for a glossy object can be determined. A mean square error in a depth measurement becomes an order of 10−2, confirming the usefulness of the proposed method.

Point source illumination stereo for objects with uniform reflectance

In an earlier report, a point source stereo method was proposed which determines the distance from the viewpoint to the surface element as well as the inclination of the element surface for the completely diffusive surface based on five density images obtained by a point source illumination. The present paper proposes a new method along the line which can determine accurately the distance distribution for the measurement in the general environment from the illumination equation with the intensity resolution of some 8 bits. A diffusive surface is considered which may contain any inclination but has a uniform reflectance over the entire surface. The distance distribution is determined by the following two procedures. In procedure 1, the common reflectance is determined by selecting the surface element with the maximum luminance in each image and combining the data. In procedure 2, the uniform reflectance is used as the constraint, and the distance distribution is determined for each surface element. The proposed method is called the solution by combined maximum luminance surface elements. An algorithm (three-source stereo method) was developed for the case of the continuous surface, where t h e distance distribution can be determined using only three images. An experiment was made for the proposed method using an 8-bit quantized image for a diffusive object. As a result, it is shown that both five-source and three-source methods can determine accurately the distance distribution with accuracy within 1 percent from the quantized intensity image data, for the measurement in the general environment.

A method for reconstructing the shape of an object from two images taken under point light source illumination

In this paper, an attempt is made to develop a new photometric method to reconstruct the 3-D shape of an object. The method proposed here is called point source illumination stereo (PSIS) and is used to reconstruct the shapes of objects from two images obtained under point light source illumination and perspective projection. It is assumed that the surface of the object is uniform, perfectly diffuse, convex and smooth. In a small-sized optical system in which both a camera and a light source are near an object, the method is applied to reconstruct the shape of an egg from images taken with a fiberscope.

Volume computation of the monument of Queen Khentkawess

Giza Plateau Mapping Project (GPMP) directed by Egyptologist Dr. Mark Lehnar achieved digital modeling of the monument of Queen Khentkawess, as known as the fourth pyramid in Giza. As members of GPMP, the authors report how this digital modeling and volume computation of it were done. First, the monument of Queen Khentkawess was scanned by laser radars with 5[mm] mesh accuracy in average. Some parts of wall of the monument on which hieroglyphs appear were scanned separately with a very high-accuracy (0.1[mm] mesh) laser scanner. Second, these scanned raw data were combined, aligned, and integrated into complete 3-D geometry model on a computer. Finally, computation of volumes of the monument was done from the geometry data of the monument, so that archaeologists could use for investigating relationship among the monument and Great Pyramids, Sphinx, and other temples around Giza Plateau. For this purpose the authors have developed a novel approach for computing volume from laser-scanned set of points (point cloud).

Geomorphological Aspects at the Giza Plateau in Egypt during the Age of Pyramid Building

The constructions of Giza pyramids were architectural landscape projects. Old Kingdom monarchs made effective use of Eocene limestone bedrocks, called Moqattam and Maddi Formation.

A method for recognition of words spoken in noisy environment

A method for recognizing words spoken in a noisy environment is proposed . A 23-channel filter bank is used to analyze noisy speec h. The output of each channel is transformed into a pulse trai n. From the autocorrelation functions of these pulse trains, the pitch period of speech is detected and the spectrum is estimated at each fram e. Word recognition is carried out by DP-matching algorithm using the distance measure weighted by the correlation coefficien t. The results of experiments where white noise, traffic noise, and an engine sound were used as additional noises show the effectiveness of this system.