The Research Of 3D Coordinates Acquisition Based On Spatial Resection

According to the conventional view of close range photogrammetry, in order to acquire absolute 3D coordinates of objects, it needs two conditions: First, it needs abundance of texture in objects and these objects are in condign condition, which can acquire stereo image pair accord with themselves quality; Second, it needs to establish some control points on the surface or around of these objects. But in many projects of close range photogrammetry, these objects themselves run short of texture and are shady, sightless, or unable to be measured directly. At the same time, it needs a mass of time to establish some control points .So based on the conventional view of close range photogrammetry, it is difficult or even unable to acquire absolute 3D coordinates of these objects.In order to deal with this situation, the paper provides a new method based on the principle of spatial resection to measure 3D coordinates of objects. This way needs fix an Aid Measuring Pole (AMP) on a digital camera. After calculating the coordination about the end point of AMP in image spatial coordinate system, if the end point of AMP touches the unknown point closely, the coordination of unknown point can be obtained using the exterior elements of image. The detailed research work can be sum up as follows.1. The paper introduces the using of digital camera in close range photogrammertry and discusses the theory and method of digital camera calibration. These include the choice principle and gist of digital camera, the content and methods of digital camera calibration. Based on the measure precision received from different distortion parameters of digital camera, the paper advocate to choose appropriate distortion parameters.2. The paper introduces the several main artificial marks of control points, and points out the main principles of selection. The ways using the geometrical relation of images to identify the control points automatically and semi-automatically as well as measure methods about their sub-pixel have been introduced. The key techniques including image division, point's position and calculation of coordinate ground points using bundle adjustment have been clearly expatiated. The paper applies these methods and techniques to establish a 2D control ground.3: The paper provides a new method based on the principle of spatial resection to acquire target's3D coordinates, discusses the principle key techniques and project, approves the path and analyses the factors which can influence the precision. Based on the research of this paper, we can design a tool based on theprinciple of spatial resection to acquire promptly absolute 3D coordinates of objects which run short of texture and are shady, sightless, or unable to be measured directly. As well as it can acquire others geometry data based on these absolute 3D coordinates.