The Study Of Inverse Lighting Based On Screen Space Normal

With the rapid development of computer graphics and computer vision technology in recent years,augmented reality,machine vision and other technologies have become new hotspot in the fields of military,commercial and entertainment.How to improve the realism and credibility of augmented reality and machine vision has become a research hotspot at home and abroad.The illumination inversion problem of how to obtain the illumination information in the 3D scene from the image is one of the key techniques to improve the reality and credibility.The requirements for scene illumination information are different for different application purposes.For example,under the condition of illumination consistency of augmented reality,it is necessary to obtain the illumination environment of the real scene,including the position of the light source and the light intensity.The intrinsic image problem in the field of computer vision requires separation and removal of highlight components of the surface of the object in the scene.It can be seen that acquisition the illumination distribution of each component in the scene is the main target of illumination inversion.In this thesis,a kind of screen space normal map is used to extract the illumination information from the scene onto the spherical surface,and then the reflection component is separated by mathematical morphology according to the regularity of the illumination reflection on the spherical surface.(1)Firstly,some physical properties of optics are described,and some common illumination reflection models are listed.The relationship between illumination reflection and normal is explained.Based on the illumination model,the illumination reflection distribution on the spherical surface has a certain regularity,which leads to the research direction of extracting the illumination information onto the spherical surface.And the decomposition of the illumination reflection component is described based on the illumination model.(2)Then use a texture mapping technology based on the screen space normal in the rendering pipeline,and establishing a mapping relationship between the illumination information of the surface of the object in the real shot image and the normal of the surface of the object by this mapping technique,so as to extract the illumination to a sphere.Therefore,the mathematical morphology operator can be constructed according to the regularity of the reflection distribution on the spherical surface.Separating the reflection components.(3)Finally,the inverse illumination is solved for the ideal simple light source scene and the image in the actual visible scene,and the inverse illumination of the infrared scene is exploratory solved.From the result analysis,the trusted illumination result can be obtained in the visible light scene.And simplify the calculation process and the image acquisition process compared to the previous solution method.