Study On Photogrammetric Method For Multi-line Intersection Structure And Its Application In Port Machinery

The port harbor hoisting machinery is a kind of typical high-risk special equipment,therefore,it is of great significance to test its key structure and provide data support for safety evaluation research.Photogrammetry,with the advantages of high efficiency in the information collection and low cost,is an ideal measurement method for port harbor hoisting machinery.However,due to the limitation of the port harbor hoisting machinery itself and the limitation in the characteristics of working environment,the efficiency and accuracy of the existing photogrammetric method can not meet the needs of safety evaluation research.This paper,based on the multi-line intersection characteristics of the key structure of port harbor hoisting machinery,has improved the existing photogrammetric method in the aspects of calibration,key point identification,homonym matching and data processing.For the main research work and achievements,this paper has:(a)Proposed the focal length calibration method with precision pointer point and realized the accurate focal length calibration based on the measured photos.On this basis,we have proposed the pointer weighting algorithm based on optical distortion model and sub-pixel iterative optimization algorithm to further optimize the accuracy of focal length calibration.The above method can significantly improve the accuracy of photogrammetric measurement in scenes with uncontrollable shooting distance represented by the measurement of port harbor hoisting machinery.(b)Proposed the automatic key point recognition and homonym matching algorithm for drawing equipment,in which the prediction model is used as the recognition benchmark,and the point groups with geometric constraints of multi-line intersection are used as the basic recognition units.The recognition accuracy of this algorithm is better than that of traditional manual recognition,and it can realize the automation of key point extraction and matching process.(c)Proposed the key point recognition algorithm based on improved Hough Transform linear recognition algorithm for the non-drawing equipment,which takes the matching result of SIFT algorithm as the regional division benchmark.This paper also proposes a matching region selection,classification and sorting algorithm based on the characteristics of multi-line intersection points,and matching homonym points matching algorithm based on improved core line algorithm,on the basis of the results of key points recognition.The algorithm can automatically extract and match the key points of multi-line intersection feature structure in complex background photos,and the recognition accuracy is better than traditional manual recognition methods.(d)Proposed an optimization algorithm of key point coordinate measurement accuracy using key point prediction model and redundant observation for adjustment operation based on the multi-line intersection characteristics of key points and revolving body structure,and an optimization algorithm of radius parameter measurement accuracy based on the weighted prediction model of revolving body radius.The above algorithm has excellent optimization effect on the accuracy of traditional algorithm measurement results under the condition of poor quality of input data and less data for adjustment calculation.(e)Designed a simulation engineering verification test to simulate the real measurement environment of the port for testing the practical application effect of the research results.The experimental results show that the above algorithms can effectively improve the measurement efficiency and accuracy,have a positive significance for the application and popularization of photogrammetric methods in ports,and provide a strong support for the related safety evaluation research.