Related Project

Read about CHI's work on site at the UNESCO Prehistoric Rock-Art Sites in the Côa Valley in Portugal.

On site in the Côa Valley, Portugal

Working on site in the Côa Valley, Portugal

CHI in Rock Art

Learn how CHI applies RTI and related technologies in studies of rock art.

Petroglyph from Legend Rock, Wyoming

Petroglyph from Legend Rock State Park, Wyoming

Learn More About CHI Technologies

Imaging an artifact at Chersonesos

Imaging an artifact at Chersonesos, Ukraine

Learn more about CHI technologies including Reflectance Transformation Imaging.

“New Reflection Transformation Imaging Methods for Rock Art and Multiple-Viewpoint Display”

VAST 2006 Best Paper Award

Highlight RTI method

Highlight RTI method using black sphere with specular highlights

About This Publication

Authors Mark Mudge, Tom Malzbender (HP Labs), Carla Schroer, Marlin Lum
Presented at VAST 2006, The 7th International Symposium on Virtual Reality, Archaeology and Cultural Heritage
Date and Location November 2006, Nicosia, Cyprus
VAST 2006 Editors M. Ioannides, D. Arnold, F. Niccolucci, K. Mania
PDF File Download (604 KB PDF)
PDF Slide Presentation Download (576 KB PDF)


In this 2006 paper, we offer two new methods of documenting and communicating cultural heritage information using Reflection Transformation Imaging (RTI). One imaging method is able to acquire Polynomial Texture Maps (PTMs) of 3D rock art with a wide range of sizes, shapes, and environmental contexts. Unlike existing PTM capture methods requiring known light-source positions, we rely on the user to position a handheld light source, and recover the lighting direction from the specular highlights produced on a black sphere included in the field of view captured by the camera. The acquisition method is simple, fast, very low cost, and easy to learn. A complementary method of integrating digital RTI representations of subjects from multiple viewpoints is also presented. It permits RTI examination “in the round” in a unified, interactive, image-based representation. Collaborative tests between Cultural Heritage Imaging, Hewlett- Packard Labs, and the UNESCO Prehistoric Rock-Art Sites in the Côa Valley, a World Heritage Site in Portugal, suggest this approach will be very beneficial when applied to paleolithic petroglyphs of various sizes, both in the field and in the laboratory. These benefits over current standards of best practice can be generalized to a broad range of cultural heritage material.