"Double mapping" is a phenomenon that occurs when true orthophotos are generated using digital surface models (DSM) in areas with occluded areas. To avoid this unwanted effect, the detection of the existing occluded areas becomes a requirement. The most popular solution is called Z-Buffer, a Computer Graphics (CG) method. This article presents the implementation of an algorithm to detect occlusion areas in true orthophoto generation using backward projection, based on a Modified Z-Buffer method. Two areas of Curitiba-PR were used for the study, as both of them were available in photogrammetric flight and MDS forms. The results outlined the behavior of this method and the way its main limitation, the M portion, can influence the suppression of double imaging formed during the generation of true orthoimages.
True Orthophoto; Double Mapping; Occlusio; Z-Buffer
