Metric capabilities of low-cost digital cameras for close range surface measurement

This paper examines the potential of low-cost digital cameras for close range surface measurement using feature-based image matching methods. This is achieved through extracting digital elevation models (DEMs) and comparing accuracies between three low-cost consumer-grade digital cameras (Sony DSC-P10, Olympus C3030, Nikon Coolpix 3100) and the proven Kodak DCS460. Surprisingly, the tests revealed that the highest accuracies were achieved using the Sony DSC-P10, not the Kodak DCS460, whilst the other two cameras certainly proved suitable for most close range surface measurement tasks. Lens modelling was found to provide a limiting constraint on final accuracies, with very small systematic error surfaces caused by residual imperfections in lens modelling. The IMAGINE OrthoBASE Pro software and an independent self-calibrating bundle adjustment were used to process these data. These tests identified an inaccuracy in the self-calibrating capability of IMAGINE OrthoBASE Pro version 8·6 and Leica Geosystems LPS 8·7, which will be rectified in subsequent software releases. The study has demonstrated that cheaper consumer-grade digital cameras have potential for routine surface measurement provided lens modelling is considered. The lead author is maintaining a web-based repository for camera calibration data, which may assist other users