Real-time Measurement Method And System Implementation Of Hull 6 Degrees Of Freedom

Since the hull has characteristics such as an irregular shape,a large target,it is not easy to use the traditional ruler,gyroscope to measure the hull six degrees of freedom However,if the markers will have certain characteristics attached to the hull,hull motion,markers along with the movement,measuring six degrees of freedom of the hull that is converted to measure markers of six degrees of freedom motion,greatly reducing the simplicity and reliability of the measurement method.In this paper,we choose 15 cm × 15 cm piece of the RGB(Red,Green,Blue)there kinds of color as markers,to be placed in different position of the hull.Processing the images of the hull motion,by two cameras from different angles for the same time,to get the geometric relationships between the two image points according to the principle of imaging camera,and then calculate the three-dimensional coordinates of the point.By obtaining a large number of feature points,the three-dimensional coordinate data of the trajectory of the hull can be reconstructed.To obtain accurate feature point coordinates need to accurately extract the feature point area,so a good method for feature detection is the core of this measuring system.In this paper,in order to ensure the real-time measurement system,we use the image pyramid algorithm to down-sample the input image to reduce the resolution of the image,and then use the two-step to detect and locate feature points,which are based on color feature of rough localization and the feature point on the accurate positioning.In the process of rough localization,using the RGB space to the Lab space transformation,K-means cluster methods to analysis image template of color components,to locate the approximate area of the target appears in the image.Then using cornerSubPix function to detect feature points within the localization region,finally finish the accurate position of feature points.The improved feature extraction and matching location method proposed in this paper has the characteristics of real-time and high precision,which provides a good powerful guarantee for the realization of non-contact hull six degree of freedom measurement system.