Kazuhide Hasegawa

The great buddha project: modeling cultural heritage for VR systems through observation

This paper overviews our research on digitalpreservation of cultural assets and digital restoration oftheir original appearance. Geometric models are digitallyachieved through a pipeline consisting of scanning,registering and merging multiple range images. We havedeveloped a robust simultaneous registration method andan efficient and robust voxel-based integration method. Onthe geometric models created, we have to align textureimages acquired from a color camera. We have developedtwo texture mapping methods. In an attempt to restore theoriginal appearance of historical heritage objects, we havesynthesized several buildings and statues using scanneddata and literature survey with advice from experts.

Isolation and characterization of Chinese hamster ovary cell mutants defective in glucose transport

Cultured Chinese hamster ovary (CHO) cells possess an insulin-sensitive facilitated diffusion system for glucose transport. Mutant clones of CHO cells defective in glucose transport were obtained by repeating the selection procedure, which involved mutagenesis with ethyl methanesulfonate, radiation suicide with tritiated 2-deoxy-D-glucose, the polyester replica technique and in situ autoradiographic assaying for glucose accumulation. On the first selection, we obtained mutants exhibiting about half the glucose uptake activity of parental CHO-K1 cells and half the amount of a glucose transporter, the amount of which was determined by immunoblotting with an antibody to the human erythrocyte glucose transporter. The second selection, starting from one of the mutants obtained in the first-step selection, yielded a strain, GTS-31, in which both glucose uptake activity and the quantity of the glucose transporter were 10-20% of the levels in CHO-K1 cells, whereas the responsiveness of glucose transport to insulin, and the activities of leucine uptake and several glycolytic enzymes remained unchanged. GTS-31 cells grew slower than CHO-K1 cells at both 33 and 40 degrees C, and in a medium containing a low concentration of glucose (0.1 mM), the mutant cells lost the ability to form colonies. All the three spontaneous GTS-31 cell revertants, which were isolated by growing the mutant cells in medium containing 0.1 mM glucose, exhibited about half the glucose uptake activity and about half the amount of glucose transporter, as compared to in CHO-K1 cells, these characteristics being similar to those of the first-step mutant. These results indicate that the decrease in glucose uptake activity in strain GTS-31 is due to a mutation which induces a reduction in the amount of the glucose transporter, providing genetic evidence that the glucose transporter functions as a major route for glucose entry into CHO-K1 cells.

Flying laser range finder and its data registration algorithm

Scanning from the air is one of the most efficient methods for obtaining 3D data of large-scale objects. For this purpose, we have been developing a flying laser range finder that is suspended under a balloon. Even though the scanning speed of the finder is quite rapid, it is difficult to eliminate the influence of the swing of a balloon. As a result the scanned data have some distortion due to the intra-scanning movement. In order to compensate this intra-scanning movement, we propose a evolutional registration algorithm which not only aligns multiple range images to determine inter-scanning movement parameters, but also rectifies distortion of range image by determining intra-scanning movement parameters. In this paper, we describe our aerial scanning system especially focusing on the design of the flying laser range finder and deformation registration algorithm. To show the effectiveness of our method, we evaluate its performance using synthesized and real data.

Motion estimation of a moving range sensor by image sequences and distorted range data

For a large scale object, scanning from the air is one of the most efficient methods of obtaining 3D data. In the case of large cultural heritage objects, there are some difficulties in scanning them with respect to safety and efficiency. To remedy these problems, we have been developing a novel 3D measurement system, the floating laser range sensor (FLRS), in which a rage sensor is suspended beneath a balloon. The obtained data, however, have some distortion due to the intra-scanning movement. In this paper, we propose a method to recover 3D range data obtained by a moving laser range sensor; this method is applicable not only to our FLRS, but also to a general moving range sensor. Using image sequences from a video camera mounted on the FLRS enables us to estimate the motion of the FLRS without any physical sensors such as gyros and GPS. At first, the initial values of camera motion parameters are estimated by perspective factorization. The next stage refines camera motion parameters using the relationships between camera images and the range data distortion. Finally, by using the refined parameter, the distorted range data are recovered. We applied this method to an actual scanning project and the results showed the effectiveness of our method.

Representing cultural heritage in digital forms for VR systems through computer vision techniques

This work overviews our research on digital preservation of cultural assets and digital restoration of their original appearance. Geometric models are digitally achieved through a pipeline consisting of scanning, registering and merging multiple range images. We have developed a robust simultaneous registration method and an efficient and robust voxel-based integration method. On the geometric models created, we have to align texture images acquired from a color camera. We have developed a texture mapping method to utilize laser reflectance. In an attempt to restore the original appearance of historical heritage objects, we have synthesized several buildings and statues using scanned data and literature survey with advice from experts.