摄影测量外文翻译--数字摄影测量和激光扫描文化遗产文档的一体化(编辑修改稿)

摄影测量外文翻译--数字摄影测量和激光扫描文化遗产文档的一体化(编辑修改稿)内容摘要：

ils. Additionally, the identification of points to be measured, being manual or semi automatic, requires a long and tedious work, especially if a considerable number of points has to be captured. The plete coverage of spatially plex objects like heritage sites can only be guaranteed, if data collection is realized from different viewpoints. Even though this is possible in most scenarios, problems can result from the fact that setting up and dismounting the plete laser system is relatively time consuming. In contrast to that, the effort to collect additional images with a standard digital camera can almost be neglected. Additionally, pared to laser scanning there are fewer restrictions on the range of measurements during image collection, which simplifies the selection of different viewpoint in order to cover the plete structure of the object. For this reason, it can be advantageous to plete a geometric model, which has been generated from the laser measurement, based on intensity images captured independently from the range data. By these means object geometry, which is not available in the range data due to occlusions is provided based on photogrammetric measurements. Thus, the highest possible degree in efficiency and flexibility of data collection will be possible, if both techniques are bined during data processing. In our approach this integration helps to improve the geometry and visual quality of the collected 3D model. During data collection the information on edges and linear surface features like cracks is based on the analysis of the images, whereas information on object geometry is provided from the laser data. Additionally, areas, which are not accessible in the laser scanner data due to occlusions are added based on semiautomatic evaluation of the imagery. By these means, a plete 3D features for the scene can be generated with sufficient and clear details. Within the paper the presented approaches are demonstrated in the framework of a project aiming at the generation of a 3D virtual model of the AlKhasneh, a wellknown monument in Petra, Jordan. In section 2 the collection and preprocessing of the relevant image and LIDAR data is discussed. This preprocessing is mainly required in order to coregister laser and image data for further processing. Section 3 exemplarily presents our feature extraction approach using the hybrid system for the left door of AlKhasneh. 2 DATA COLLECTION AND PREPROCESSING The collection of the data, which has been used for our investigations, was performed in cooperation with the Hashemite University of Jordan. One of the project goals is the generation of a 3D documentation of the AlKhasneh monument in Petra city, Jordan, which is depicted in Figure 1. AlKhasneh Monument The ancient Nabataean city of Petra has often been called the eighth wonder of the ancient world. Figure 1. AlKhasneh facade, Petra Petra city in southwestern Jordan prospered as the capital of the Nabataean empire from 400 . to . 106. Petra39。 s temples, tombs, theaters and other buildings are scattered over 400 square miles, these architectures are carved into rosecolored sandstone cliffs. After a visitor enters Petra via AlSiq, a twokilometer impressive crack in the mountain, the first facade to be seen is AlKhasneh, which is considered as the bestknown monuments in Petra city. The AlKhasneh facade is 40m high and remarkably well preserved, probably because the confined space in which it was built has protected it from the effects of erosion. The name Al Khasneh, as the Arabs call it, means treasury or tax house for passing camel caravans, while others have proposed that the Al Khasneh Monument was a tomb. Behind the impressive facade of AlKhasneh, large square rooms have been carved out of the rock [Sedlaczek, 2020]. Sensors Applied For point collection, the 3D laser scanning system GS100, manufactured by Mensi ., France was applied. The scanner features a field of view of 360?in the horizontal and 60?in the vertical direction, enabling the collection of full panoramic views. The distance measurement is realized by the time of flight measurement principle based on a green laser at 532 nm. The scanning range of the system allows distance measurements between 2 and 100 meters. The scanner抯 spot size is 3 mm at a distance of 50 meters。 the standard deviation of the distance measurement is 6 mm for a single shot. The system is able to measure 5000 points per second. During data collection a calibrated video snapshot of 768x576 pixel resolution is additionally captured, which is automatically mapped to the corresponding point measurements. In addition to the laser data, digital images were captured for photogrammetric processing using a Fuji S1 Pro camera, which provides a resolution of 1536x2034 pixel with a focal length of 20 mm. Measurement Configurati。