طراحی معماری به کمک کامپیوتر مبتنی بر عکاسی تاریخی : مدل سازی اطلاعات ساختمان های تخریب شده با قابلیت های مهندسی معکوس

This paper is about single three-point perspective historical photography-based CAAD modeling (amateur camera calibration, pose and 3-d reconstruction) of man-made environments, buildings and monuments, rich in geometrical regularity. The proposed method, gains profit from the presence in the image (historical photography) of three vanishing directions and two orthogonal object edges with known length ration, and then focuses on the graphical estimation of the skew intrinsic parameter of the uncalibrated camera (i.e. the angle of dot's x and y optical axes, in photography plane), dealing in this way even with the skew presence case (non-rectangle dot). The presence of skew is not a negligible factor in historical photography of early 20th century years, due to dot optical axes failure (carelessness manufacturing) or collapse, as well as the twist effect (distortion) from the undocumented film development process in 1920s. The graphical recovery of the skew factor is the main contribution of the paper to the pose and CAAD literature. It is shown that a single three-point perspective amateur photography, even with the presence of skew, is adequate for calibration, pose and planar structure (building façades) recovery, if the usual in building's architecture geometric clues are present (i.e. planarity, orthogonality and parallelism) and some metric data (e.g. length and width of demolished building's dimensions) are available. The proposed method was validated on a simulated cuboid and demonstrated on a number of demolished historical buildings for which only one uncalibrated (and skewed) photography was available. The accuracy evaluation shows that the method is suitable for CAAD modeling applications regarding demolished buildings and monuments of the early 20th century years (2% relative accuracy, i.e. 40 cm for a 20 m façade, included the metric data inaccuracy). The method is of interest for architecture, archaeology, reverse engineering and virtual reality.