Perspective Projection Error In Visual Inspection Of The LAMOST Focal Plane

The Large Sky Area Multi-Object Fiber Spectroscopic Telescope is a quasi-meridian reflecting Schmidt telescope laid down on the ground with its optical axis fixed in the meridian plane. As one of the national major scientific projects LAMOST has large diameter and large field of view. The focal plane that plays an important role in the accurate tracking of astrology was composed of optical fiber which belongs to optical fiber positioning unit. Therefore, the position accuracy of optical fiber positioning unit in measurement is particularly important. Consider the various factors, visual inspection non-contact measured is chosen, machine vision will help person to complete the observations and judgments, could greatly improve detection accuracy and speed. After CCD camera calibration capture images to detect position of the optical. In the process of capture images through CCD camera, It is possible that microchip plane of camera CCD is not strictly perpendicular to optic axis and object plane is not strictly perpendicular to optic axis. Both of them will bring Perspective Projection error. In visual inspection system through analysis of the process of detection and image data, Research the perspective error is chosen. Main of the research content as following:First introduce the content of machine vision, established internal and external calibration modeling of the camera, also established Standard polynomial calibration modeling of the camera, get the distortion error of two models. According to the CCD camera and the focal plane relative position, established the perspective transformation modeling of the entire focal plane fiber positioning unit through the theory of perspective transformation in space. Calculated the errors of the perspective transformation are obtained the law of variation. Analysis the data of the visual inspection experiment obtained the law of actual variation. According to the CCD camera and the focal plane relative tilt position, established the tilt transformation modeling of the entire focal plane fiber positioning unit through the theory of Three-dimensional transformation and view transformation. Calculated the errors of the tilt transformation are obtained the law of variation. Analysis the data of the visual inspection experiment obtained the law of actual variation.