Research In Calibration Technique Of Helicopter Rotor Common Taper Measurement System Based On Panoramic Vision

Panoramic vision system can achieve greater than a hemisphere field of view imaging range, and camera on the symmetry axis of rotation will not cause much substantial impact on the scene. Its excellent properties have been widely applied to many areas of robot navigation,3D reconstruction, visual surveillance, virtual roaming, and visual measurement; it has been one of the research focuses in recent years. However, panoramic vision system shot to get the perspective image is at the expense of the image distortion. The generation of distortion is with regard to the panoramic view of the structural design, the mirror parameters and camera performance In order to get the visual image or scene reconstruction, establishing the point correspondence between a complete model of the estimated pixel point and space point is needed. That is to complete a calibration process. Calibration is the essential step for camera to obtain three-dimensional information from the two-dimensional images. This paper studies the panoramic vision applications to helicopter rotor common taper measurement when using the calibration method and makes a rotor taper measurement based on the calibration.First panoramic vision of the development process and the current research situation at home and abroad are described. The catadioptric panoramic vision system as the most widely used panorama mode, in order to facilitate the follow-up calibration, measurement research, conducted a focuses on catadioptric panoramic view. Perspective model, radial distortion and spherical models, mainly spherical projection model proposed continuous improvement, proved to be not only adapted to a single viewpoint system, fisheye lens for non-single viewpoint imaging process can also use this model to explain. Then combined with the research background of this thesis describes the measurement of helicopter rotor taper.Then a calibration method for catadioptric systems based on spherical projection model is proposed. This method is flexible and easy, but mainly for calibration of the single viewpoint panoramic view. Therefore, given a calibration method based on an arbitrary image, the single viewpoint constraint not required, you can estimate the positional relationship of the mirror parameters and relative camera. But the second method used on the helicopter measurement needing a strong constraint, so the method is ease to calibration but not easy to measure. Therefore mainly propose a helicopter rotor taper measurement method according to the calibration principle of the single viewpoint. This method modeled the calibration principle of the spherical projection, pasting the calibration block on the blade, then the rotor taper difference can be measured.Finally, after the instructions for the measurement principle and the comparison of two methods of calibration method, choose the experimental method based on spherical unified model calibration. Simultaneously according to the new method pasting the calibration block on the blade, and then determine the relative positions of rotor system and panoramic system systems. According to the conversion of this spatial relationship can solve rotor taper difference. And measurement results validate values obtained in accordance with laser measurement, it approve that this calibration technique and measurement technique are working.