Rock Art Documentation

Rock art documentation by using multispectral is becoming popular in the cultural heritage domain. Multispectral is a camera with multi-lenses and sensors, which can take pictures of an object by multi-wavelength at the same scene. Usually, the advantage of using multispectral is it can detect an invisible object because it equipped with Near Infra-red (NIR) band, which is useful in reflecting the invisible spectrum. However, in the application of rock art documentation, multispectral is only focused on radiometric analysis, although multispectral images principally can be used for generation of orthophoto and digital surface model. Problems of processing multispectral photos by using close-range photogrammetry (CRP) involves band-to-band registration for alignment, because of the images have a different view angle, and calibration of the images becomes complicated.
The 3D model generation processes automatically, including determination of camera calibration parameters, keypoint extraction, image matching and dense point cloud generation. However, the 3d models generated through the automated process do not give high accuracy since it does not emphasize metric accuracy. Therefore, the purpose of this study is to enhance rock art documentation by using multispectral photogrammetry. This research will focus on multispectral camera calibration techniques and photogrammetry network design in the application of rock art documentation. The first phase will design camera calibration method by using collinearity equation, as well as band-to-band registration problem. The second phase of this study will focus on photogrammetry network design to develop appropriate measurement techniques using multispectral cameras and processed using the SfM / MVS photogrammetry