Research And Application Of The Short Focus Length Camera Calibration In Wide Field

The non-contact measurement of large-size object is being paid more and more attention as a result of the rapid development of computer vision. It can not only be implemented through the data registration measurement, but also be completed by the overall measurement. The overall measurement is relatively simple for only a calibrated camera with short focus length in wide field is needed. The first issue to tackle is the short focus length camera calibration in wide field for the non-contact measurement of large-size object. In addition, the traditional calibration algorithm requires a calibration template whose size corresponds to the object to be measured. Therefore, the design of calibration template for camera calibration in wide field is of much concern.The main content of this thesis is the research and application of the camera calibration with short focus length in wide field. A new scheme is explored on the basis of the advantages and disadvantages of the existing short focus length camera calibration algorithms. Furthermore, a relevant calibration template scheme is proposed. Finally, what is obtained from the camera calibration with short focus length in wide field is applied to the actual measurement, verifying the correctness and practicability of the proposed calibration algorithm.Firstly, the basic theory of camera imaging is elaborated, which consists of two kinds of imaging models, namely the linear model and the non-linear model. The realization of Zhang’s calibration algorithm is introduced in detail.Secondly, a current concentric circles detection algorithm is recommended briefly, to which some improvement plans are applied because of the exsisting limitations. The improved algorithm is adopted in this thesis and is proved to be successful through actual experiments. Concentric circles are used as the pattern on the calibration template due to its numerous advantages.Thirdly, the detailed design of the template for the camera calibration with short focus length in wide field is introduced emphasisly. Besides, a calibration algorithm based on the registration template is suggested for the short focus length camera calibration in wide field, which is confirmed in fact. The result of the camera calibration with short focus length in wide field is applied to the actual measurement.Finally, The object to be measured is a hoop-rib deployable antenna whose size is relatively large. The antenna is flexible and easy to be deformed for various external factors. The non-contact overall measurement scheme is adopted due to the characteristics of the antenna, which can simplify the measurement procedure greatly and reduce the time spending on the actual measurement. The overall measurement of the antenna is put into effect based on the binocular stereo vision theory in this thesis. The measurement precision satisfies the requirement, indicating the rationality and feasibility of the camera calibration with short focus length in wide field.