Analyzing Dmc Performance in a Production Environment

Since December 2004 the Institut Cartogràfic de Catalunya (ICC) has taken more than 135 000 digital aerial images with two Digital Mapping Cameras (DMC) from ZEISS/INTERGRAPH (Z/I). After three years of experience and with the new, fully digital, production lines well established, this paper analyses the performance of the digital camera in a true production environment, specially compared to the older production lines based on digitized analogue images.The accuracy assessment is studied for every single step of the mapping production line: aerial triangulation, DEM (Digital Elevation Model) generation, stereo plotting and orthophoto quality (image resolution). DMC images of 45cm and 7.5cm pixel size, from several production projects, are analysed and the results are compared to the respective results of analogue workflows (with the same pixel size when scanned at 15μm). The accuracy assessment for the aerial triangulation and stereo plotting is done with independent check points and with Lidar data for the DEM evaluation. The analysis of the photointerpretation is based on the observations of experienced and well trained operators. To asses the resolution of DMC images, a tool based on the computation of the Line Spread Function has been developed. The method takes into account the distance of this kind of structures to the center of the image, both along and across flight direction, in order to quantify the effective resolution power of the DMC and the analogue images.Final conclusions are drawn from the performance analysis of the aerial triangulation, DEM generation, stereo plotting and image resolution in a production environment.