Testing and application of a low-cost photogrammetric recording system suitable for cultural heritage recording

In the field of conservation, cost effective and easy to use methods are required to record cultural heritage and close-range photogrammetry has proved effective in this area. Off-theshelf digital cameras can be used to rapidly acquire data at low cost, allowing non-experts to become involved. Exterior orientation of the camera during exposure needs to be known for every image, traditionally requiring known coordinated target points. Establishing these points is time consuming and costly and using targets can be often undesirable. To overcome these problems a recording system is being developed that is capable of deriving the exterior orientation of a camera during exposure directly and cheaply. The system comprises an offthe- shelf digital SLR camera, a small-size 3D orientation sensor and a GPS antenna. All system components were assembled in a compact and rigid frame that allows calibration of the rotational and positional offsets between the components. The project involves collaboration between English Heritage and Loughborough University and the intention is to test the system at several heritage sites during 2010. It is expected that results from the first heritage site are presented at the conference; allowing assessment of the performance of the recording system, the stability of the calibration and the system’s practicability in a heritage recording environment. Intermediate results of the ongoing data analysis indicate that the data recorded by the system can indeed meet the accuracy requirements for heritage recording with either a single or even no control points. As the recording system has been configured with a focus on low-cost and easy-to-use components, it is believed to be suitable for heritage recording by non-specialists. This offers the opportunity for lay people to become more involved in their local heritage, an important aspiration identified by English Heritage.