Sun Shadow Positioning and Timing Based on UnrealEngine 4

It is an important topic in the current image processing and analysis to use the photos or video to determine the shooting position and time. Analyzing the change of the object's sun shadow is an effective way to solve this problem. In this paper, the 3D scene photography is modeled to simulate the virtual reality by the software UnrealEngine 4 and the scene of the video can be reproduced accurately. The values of the solar angle parameters in the virtual environment can be shown on the software interface directly, so the solar elevation angle and solar azimuth angle can be fitted with these data to simplify the unnecessary mathematical derivation and programming. Furthermore, a measurement that reflects the deviation of the theoretical values calculated by the formula and fitted values is set as Difference of Angle. Finally, with the minimum Difference of Angle as the optimization goal, the rough possible range of the optimal solution is determined by the discretization search and the optimum solution is calculated by the least squares method. The result shows that this model is generally-used and operable. This method based on virtual reality technology has high maneuverability and accuracy, with good scalability for the number of unknown parameters.