3d Photogrammetric Recording Using Dlt and Cad

Novice users currently use Digital Photogrammetric Applications increasingly in order to record close range objects of great cultural value or for the monitoring of sensitive objects or procedures (industrial and medical applications). Monoscopic procedures (digital rectification) have been embedded recently, in many popular commercial applications. Also, CAD and CAM applications are gaining even more their use by people of low knowledge background in Photogrammetry, namely Archaeologists, Medical Doctors, Mechanical Engineers, etc. 3D photogrammetric applications are very important and could be part of the every day activity by the above-mentioned professionals. Since the real world is 3D and the demand for accurate recording and representation is increasing even more with the development of new high tech computing systems and reproduction devices, the development of easy to use 3D photogrammtric software applications is more than ever a necessity. Ground Control Points (GCP) measurements, bundle adjustment of colinearity equations and camera calibration procedures applied to stereoscoping and convergent photogrammetric images offer the most efficient and accurate solution. However, the above-mentioned tasks are hard to be applied by many potential users with low implication in photogrammetric projects. There are also some cases where these tasks cannot be applied due to the uncertainty or short of information about basic camera calibration parameters. In these cases, Direct Linear Transformation offers a way to extract reliable 3D information with just the use of some GCPs which could be easily measured using modern conventional reflectorless Total Stations. This paper is describing our attempt to provide a low cost CAD software application embedding the DLT photogrammetric processing to create accurate 3D drawings of close range objects. The use and distribution of the application is free for academics while the demands in hardware configuration (CPU and graphics card) are very low.