Historical Materials No.86

Photomap Images of the Kitora Tomb Murals

English Summary

Photomap Images of the Kitora Tomb Murals

Nara National Research Institute for Cultural Properties

Publications on Historical Materials Volume 86

　This is a report contains technical research on making photomap images of the Kitora tomb murals.

　It was not able to make a measured drawing without any contact to an object, In a common method of photogrammetry, it was hard to combine several pictures to produce an accurate image. Therefore, we tried to apply the method of photomap to obtain precise photo images and measurement data of the Kitora tomb murals.

　The method of photomap is a kind of photogrammetry; however, unlike conventional methods, it produces an accurate picture and measurement drawing, analyzing and synthesizing several split photo data taken by digital camera.

　The steps go as follow; first, to analyze distortion ratio of lens to be used; second, to calibrate the shot images according to the distortion ratio of the lens; third, to combine the calibrated images to obtain an accurate picture.

　In a common method of photogrammetry, it is necessary to measure the coordinate data of placed targets in advance; however, it was not able to set targets in the chamber in this case. Alternatively, we placed a scale in the chamber, and took several pictures including the scale from each direction. Instead of targets, we selected some specific locations such as a part of mural and plaster as coordinate points. We took more than two images of each point from different angles, and analyzed the data of images to calculate the coordinate value of each point. Based on the data, we carried out a three-dimensional analysis (by the soft ware of PhotoModeler) to produce three-dimensional data of the object and to make measured drawings. Finally, we combined the photo images precisely according to the measured drawings.

　This photomap achieves high-precision pictures and drawings measuring to an accuracy of ± 3 mm between two measurement points calibrating 1,000 mm.

　In the Kitora tomb, all the murals have been removed and relocated by the spring in 2010, preventing further deterioration due to mold and failing. Therefore, this photomap is the only record of the original state of the Kitora tomb murals. This document will offer fundamental data for the future.

Editor

Inoue Tadao

Contributors

Inoue Tadao  Tamada Yoshihide  Okada Ai

Kawase Toshio  Shimano Satoshi  Okumura Yasuyuki

Photographer

Inoue Tadao

Contents

Preface

I Legend

　Outline of research at the Kitora tomb                                   3

　Outline of photomap images                                    8

　Selection, design, and production of eqepment and materials                         9

　Outline of photomap making                                    13

　Process of photomap making and diary report                                     15

　Data analysis and production of photomap images                             19

　Conclusion                                    23

　English summary                                        24

II Plates