Research And Implementation On Improvement Of Omnidirectional Image Unwrapping

Omnidirectional vision is a vision system based on reflector,which captures scene of 360 degrees level direction once.Compared with traditional vision system,omnidirectional vision is of wider view that is suitable for various applications in real-time surveillance fields.One omnidirectional image contains information of one level circle scene, however the image is seriously distorted,which isn't capable for practice application unless the scene information can be correctly extracted from omnidierectional image.Firstly,current research and applications of omnidierectional vision technology are introduced.Through specific analysis of geometry light routing in hyperboloid omnidirectional vision system,imaging process of omnidirectional vision is explained in detail,and technique for unwrapping one omnidirectional image to get panorama image and rendering is brought up in this paper.In unwrapping process,traditional methods easily make image pixel discontinuous which causes low image quality,especially for low resolution omnidirectional image.In this paper,quadratic interpolation method is applied for athwart projection transform,which improves image quality.According to athwart projection formula,trigonometric function table-checking method is induced,based on which,massive trigonometric function operation complex is reduced and unwrapping performance is improved.Because the process of omnidirectional vision unwrapping contains complex operation,on the other side,multimedia process makes OS costs plentiful CPU.Both of above will be a bottleneck for omnidirectional vision unwrapping process.Aiming at this bottleneck,DirectShow filter for unwrapping omnidirectional image is designed and implemented.The filter makes full use of graphics card acceleration promising higher performance of graphics card,cost less CPU,what makes the unwrapped panorama video playback more fluent.Omnidirectional vision platform,based on DirectShow filter developed in this paper,implements functions of unwrapping omnidirectional image,video,and real-time video stream to panorama or perspective images.The design and specific implementation,including operations of software and performance evaluation,are explained simply.