3D Modeling of Earthenware by Using Video Camera

Tsukasa Hosomura, Tetsuo Ohta*
 Tokyo Denki University, Ishizaka, Hatoyama-machi, Hiki-gun,
Saitama, 350-0394, Japan
Tel: +81-492-96-2911, Fax: +81-492-96-5311
Email: hosomura@ia.dendai.ac.jp
*Taiyo Survey, 2-114-8, Imaisurugi-machi,Oyabe,
Toyama, 932-0051,Japan
Tel: +81-766-67-3853, Fax: +81-766-68-1183



Abstract
By putting the video camera on the mount, which rotates at the steady speed, and taking the images of 360 degrees. It would be able to easily realize the 3D measurement of the object. In this study, such system was produced experimentally, and measurement accuracy was examined.

Introduction
Generally, 3D measurement of most equipment uses the principle of the triangular measure. There are several methods for example stereo method using the binoculus, spots projected method, pattern projected method and moire topography, etc. Stereo method is the passive method, other methods are active method, which projects the light. Stereo method using two cameras is called the binoculus stereoscopic vision. This method can be got 3D information of all points in the scene. However, it is difficult to find out the corresponding point in both scenes. In 3D modeling of the earthenware, distance measurement of plural point on the object is sufficient in most cases. It is possible to calculate the distance to the corresponding point, which has reflected on the scene obtained from many directions on the horizontal surface. But, it is difficult to get many directions from stile camera. It was considered to use of video camera for this situation. By putting the video camera on the mount, which rotates at the steady speed, and taking the images of 360 degrees. It would be able to easily realize the 3D measurement of the object. In this study, such system was produced experimentally, and measurement accuracy was examined.

Outline of the System
This system has been composed of digital video camera (SONY, Digital 8 Handycam, DCR-TRV310K) and servomotor ( FUJI ELECTRIC, GYC101DC1-S ). And, it is made to decelerate using the gear so that the camera may accurately be made to rotate in 1 periphery fixed minutes.

Measuring Method of the Distance
This equipment is set at 3 positions (camera A, camera B, camera C) on the identical circumference, and video scenes of 360 degree circumferences are obtained, and the images are incorporated in personal computer by the frame rate ( 30 scene/second ) equal to the general television. The distance from camera to the earthenware is about 10m. Some markers are in the surface of the earthenware. By putting the video camera on the mount, which rotates at the steady speed, and taking the images of 360 degrees. It would be able to easily realize the 3D measurement of the object. By counting the scene number of one camera (for example camera A), the angle from the direction of other camera (for example camera B) to the target marker can be calculated. Angle from the direction of camera A to the same target marker can be calculated by using the other camera B. As the result, distance from camera A to the target marker can be found out. The distances from each camera to the markers are calculated by using the above method.

Figure1 Image sequence of obtained movie Figure 2 Measuring method of the angles


Comparison Between Experimental Result and Measured Distance
The measurement was carried out using this system. Analysis of image sequence did not finished. We will show the experimental result at the workshop. Measurement accuracy will be also examined. If we have time, we can show 3D model of the earthenware.

Summary
In this system, there are some merits compare with conventional surveying method. Only one stuff is sufficient for measurement. Images obtained from video camera can be memorized. The object can be freely chosen.