In this episode I talk with Yang Cai about his research work doing 3-D scanning of gravestones and rock art. This new technology allows scholars to reveal information and patters thought lost to the ages by setting a laser line on a stone and measuring the refraction of this line, which allows the researchers to measure depth and reveal patters that might not be noticeable to the naked eye. A Senior Systems Scientist at CyLab, Dr. Cai is founder of Visual Intelligence Studio at Carnegie Mellon University. He is also a dedicated artist and stone carver, which has attracted him to scanning both historical and prehistorical stone carvings. Since Dr. Cai’s professional research interests include image understanding and ambient intelligence, he married his interest in in stone carving with his science to produce a useful tool and system, which he hopes will be made available to the public some day. While his 3D scanning does reveal faded data, he cautions that in order for this system to work some residual data must be present. This caution coupled with the recent escalation of erosion and damage to many stones from acid rain, makes this avenue of great interest to me as a material culture scholar and gravestone enthusiasts.