The Digital Archive of Sculptures of Tien-Shen Poo in Early Taiwan History Ying-Hsiu Huang Department of Industrial Design, Tung-Hai University, Taichung, Taiwan [email protected] Abstract. The traditional sculptures with posture and beauty are created by the fingers of sculptors, and these traditional techniques cannot be replaced by con- temporary computer technologies. However, based on the development of 3D scanning technology, computers have more influences on sculptures. In terms of preservation, the sculptures can be permanently preserved in the form of a computer triangular mesh surface, which could be stored and distributed in any digital formats, and also can be replicated by rapid prototyping or computer automatic cutting. The aim of this project intends to permanently preserve four serious sculptures of a famous sculptor, Mr. Tien-Seng Poo, from the early Taiwan history. In addition, this project is not only proposing a standard process from 3D scanning to texture mapping, but also demonstrating some ap- plications of exhibition, such as virtual reality, augmented reality, and rapid prototype, at the end of this project. Keywords: Digital Archives, 3D Scanning, Virtual Reality, Augmented Reality, Poo Tien-Seng. 1 Introduction In the past decade, there are more and more organization of governments and educa- tional institutes interesting in preserving historical and cultural heritages around the world by varieties of methods and devices. The major methods and equipment for documenting and surveying of historical and cultural heritages are: traditional manual methods, topographic methods, photogrammetric methods, and scanning methods [1]. Real 3D objects can be reconstructed automatically by using 3D scanning methods with the significant advantages of their high accuracy in geometry measurements [2]. Moreover, Blais [3] has evaluated various commercial range scanning systems. In General, most of the scanning methods demand a series of sequent steps for object geometric and texture acquisition and registration. Due to the well-developed of 3D scanning technologies in contemporary computer graphics [4], a variety of 3D scanning methodologies have proposed major solutions for generating realistic detailed 3D replicas. Real objects or elements usually could be scanned and formatted by using triangulated meshes, supported by all commercial 3D graphics hardware and software. On the other hand, in the process of texture acquisi- tion, Bernardini and Rushmeier [5] have addressed some mapping techniques onto the M. Ioannides (Ed.): EuroMed 2010, LNCS 6436, pp. 343–355, 2010. © Springer-Verlag Berlin Heidelberg 2010 344 Y.-H. Huang geometric model. By doing so, their method not only could exploit images of the object acquired by digital camera from different angles of viewpoints, and reconstruct the geometric model by using photogrammetry, but also is a low-cost and useful method when direct access to the object is not allowed. Although several methods for 3D digitization could archive high geometric resolu- tion of cultural artifacts, there are still some weaknesses of mapping high textural resolution on complicated historical objects, such as sculptures, for digital preserva- tion and virtual exhibition. This project attempts to form a stand process from 3D scanning to high textural mapping for historical sculptures of a famous sculptor in early Taiwan history. Therefore, a complete process from 3D scanning of real sculp- tures to texture mapping of multiple-angle of viewpoints, and to virtual museum and their applications, will also be proposed at the end of this project. 2 Mr. Tien-Seng Poo Mr. Tien-seng Poo is a famous deceased sculptor from the early periods in Taiwan. He is mainly famous his bronze sculptures of half-length portraits, such as the sculp- tures of the Father of Chinese, Dr. Sun Yat-sen, in front of Zhongshan Hall, the late president, Chiang Kai-shek, on Dunhua Road, Wu Feng in Chiayi, etc. By cooperat- ing with Professor Hao-ming Poo (the eldest son of Tien-seng Poo), this projects uses 3D technology to digitalize and preserve the works of Mr. Poo. In addition, the “Vir- tual Sculpture Gallery of Mr. Tien-seng Poo” is constructed to exhibit the works of Mr. Poo, via virtual space. Mr. Tien-seng Poo was born in Chiayi, Taiwan in 1912. At the age of 19, he went to Japan to learn sketching and painting Nihonga (one kind of old Japan drawings), and he eventually transferred to the division of sculpture. He was one of the earliest Taiwanese artists to study abroad in Japan. He created more than 200 pieces of sculp- tures in his life. The works in his early days, such as “Wife” (Fig. 1, left), created in 1941 for his wife in their second year of marriage, which presented simplicity and soft outlines textured in mud, and expressed his love for his wife. Fig. 1. Left: Wife (1941, bronze 24×11×10cm); Right: Child Carrying A Dog (the third son carrying a dog, 1956, bronze 35×19×20cm) The Digital Archive of Sculptures of Tien-Shen Poo in Early Taiwan History 345 Some of his works were inspired by his life, for example, Child Carrying A Dog (Fig. 1, right) was created during a leisure afternoon when Mr. Poo asked his third son, who was carrying a Pekingese, to remain still, and used mud to create the sculpture. Al- though it was an improvisation, the sculpture revealed good posture and smooth lines. In 1996, at the age of 85, Mr. Poo completed his last piece of art, a memorial bronze statue of teacher Ching-chuan Lin. He spent four years, five months, and 15 days to create the work, which is now erected in Zhingshan Art Park nearby the Taipei Fine Arts Museum. Mr. Poo died of gastric cancer at the National Taiwan University Hospital on May 31 at the age of 85. He created as many as 223 pieces in his life, including the categories of family, personage, animal, outdoor memorial stat- ues, a gymnastic series, and memorial head statues. The processes of the digitalization of 3D scanning required a great deal of labor and equipment; therefore, a total of 56 small-scale sculpture pieces were scanned first, including 11 pieces of family sculp- tures, 19 pieces of personage sculptures, 16 pieces of animal sculptures, and 10 pieces of the gymnastic serial sculptures. Table 1. Statistical table of the works of Tien-seng Poo (arranged by Hao-ming Poo and Yi- chun Poo in July, 2006) No. Categories Number 1 Family 11 2 Personage 19 3 Animal 16 4 Gymnastic 10 Subtotal (1+2+3+4) 56 scanned in this project 5 Outdoor 14 6 Body 63 7 Head 90 Total 223 total The project for building the digital archive of Tien-seng Poo includes three stages. The first stage is the 3D scanning and digitalization of sculptures. The second stage is the 3D texture mapping. The final stage is the presentation and application of digital- ized sculptures. The procedures of the project are arranged as follows: (Fig. 2) Fig. 2. Arrangement of the project procedures 346 Y.-H. Huang 3 3D Scanning of the Mesh Surfaces of Sculptures The main purpose of the first stage is to employ 3D scanning technology to convert the sculptures into triangular mesh surfaces in the computer, which are permanently pre- served, undamaged by time or environment. As for the process and technology of 3D scanning of sculptures, there are different operating procedures for different scanners. In terms of the project, the 3D scanning of mesh surfaces could be divided into four steps, namely, the scanning of partial blocks, adjustments of relevant positions of the blocks and meshes, automatic overlapping of blocks and meshes, and mesh patching. 3.1 Scanning of Partial Blocks The 3D scanner utilizing in this project is Desktop 3D Scanner, made by NextEngine Inc. (http://www.nextengine.com) (Fig. 3). The scanning field is ranging from 5.1” x 3.8” (Macro) with 400 DPI to 13.5” x 10.1” (Wide) with 150 DPI. The dimensional accuracy are ±0.005” in Macro Mode, and ±0.015” in Wide Mode. In addition, there is no limitation on the size of sculpture by using composite-captured software, ScanStudio™. Fig. 3. Desktop 3D Scanner by NextEngine Inc. (http://www.nextengine.com) Therefore, the difficulty in 3D scanning sculptures is that one sculpture cannot be entirely scanned in one step because it is a 3D object. Moreover, there is a restriction on the scanning area of the scanner itself. Therefore, in the scanning step of partial blocks, a sculpture would be divided into three or four layers in order to conduct a preliminary scan (Fig. 4, left). In addition, a single circle scan of each layer must be conducted prior to continuing with the next step of adjustments of positions. How- ever, at present, some scanners are equipped with a mechanical device to rotate the object being scanned, which achieves the completion of scanning 3D mesh surfaces in one step. However, such scanners are very expensive. After completing the scanning of three or four layers, there remained many faces that could not be scanned, such as the hindbrain and mandible of Fig. 4 (left), and many parts had to be rescanned alone by adjusting the scanning angles. After obtaining the The Digital Archive of Sculptures of Tien-Shen Poo in Early Taiwan History 347 mesh data, and the meshes of specific parts by multilayered scanning, the adjustment of positions are conducted in the next step. 3.2 Overlapping of Blocks and Meshes The second step in constructing the 3D mesh surfaces is to adjust the 3D spatial posi- tions of the meshes of different partial blocks, and assembling them (Fig. 4, Right). The more advanced 3D scanning equipments, as mentioned above, could automati- cally assemble layers of mesh surfaces.