Study On The Embedded Digital Close-Range Photogrammetry System

The traditional digital close-range photogrammetry system takes computer as the hard core,which has some advantages such as abundant functions, high computing capability, highprecision and so on.But it also has some problems such as huge volume, high power, difficultiesin integration, and dependenc on human-computer interaction, which limites its application inspacecraft rendezvous and docking, planetary patrol vehicle, intelligent control and so on.Currently, the embedded system widely used in industry domain, which takes the embeddedmicroprocessor as the hard core, is characterized by its small volume, power saving, easy forintegration, high efficiency, good reliability and so on. With the rapid development of LargeScale Integrated (LSI) technology, the computiong capability of embedded microprocessor wasgreatly improved, and had the capability in performing complex photogrammetry calculationtask. In the thesis a set of embedded digital close-range photogrammetry system based on DSPwas designed and established by combining the embedded processor with the photogrammetryprocessing technology, and main study focus was put on software and hardware components ofthe system, camera calibration method, coded target recognition, photogrammetry processingalgorithm and etc. The main work and the innovations of this thesis are described as follows.1. A summary and analysis was given on the principle, technique characteristics anddevelopment of the embedded system. It was pointed out the feasibility of establishing theembedded digital close-range photogrammetry system, and analysis was given on its keytechnologies.2. By applying DSP to the photogrammetry processing technology, a camera calibration dataprocessing method based on DSP was designed, and investigation was put on the criticaltechnologies such as the realization of calibration model, data transmission method, calibrationalgorithm and so on. The experimental result shows that this method can obtain the similaraccuracy to the traditional method, and its computing speed can reach real-time demand.3. Aiming at solving the low recognition rate problem of the traditional gray one and itsincompatibility with the embedded system, a set of color point distribution coded target wasdesigned, which did not only simply the decoding procedure of coded target by utilizing thecolor information, but also highly improve the recognition rate, the positioning accuracy andincrease the code number. The design of this target decoding method is easy and advantageousfor realizing the embedded system.4.Based upon the embedded data processing technology and digital close-rangephotogrammetry technology, several key technologies in the embedded3D reconstruction systembased on close-range photogrammetry were studied and realized, including exterior orientation, corresponding point matching, model point computation, scene3D visualization and so on.Results of two sets of experiments validated the correctness and reliability of each technology.5.By combining the embedded data processing system with digital the close-rangephotogrammetry technology, a set of embedded digital close-range photogrammetry prototypesystem based on DSP was designed. This system encompassed the whole processing from thestereo-image grabbing, and photogrammetric processing, to scene3D reconstruction. In addition,the system’s performance was tested and analyzed by experiments. It was also pointed out thedevelopment directions and application fields of the embedded digital photogrammetry system.