Video Shadow Positioning Technology

This paper mainly studies the technology of accurately positioning the imaging position through the changes of shadow length in video. 3D modeling software SketchUp is applied to conduct hidden line processing on images and obtain the actual shadow length of objects in the video. Take into account the impact of various factors, a precise model that the shadow length changes over time is established; on this basis, a model that reversely positioning the shadow position is also constructed, with the purpose of maintain the minimum sum between object height variation and rotation angle error, besides, latitude and longitude are regarded as the independent variables. As the function relation of parameters is both complex and non-linear, so grid method is firstly adopted, to obtain the approximate location of possible measuring areas, and then based on the initial value to obtain a corresponding precise position by quasi-Newton iterative method, finally obtain the actual shooting location of objects.