Research On Video Image Stitching Technique Based On Fisheye Lens

With the high-speed development of national economy, problem of traffic safety hasbecome a problem cannot be ignored with high popularity of vehicle in the people’s life. Thetraffic accidents arise more and more frequently. In recent years, more and more electroniccommunication techniques are equipped in vehicle, how to help the driver parked the vehiclesafely and easily become one of the important research issues in recent years. Therefore,parking assist system becomes a worth subject.In this paper, we present a specific implementation plan of parking assist system basedon a panoramic imaging，On the basis of the research of the key technologies of cameradistortion correction and image stitching，we analyze the disadvantage of them and improvethem, and finally, we implement the method of parking assist system based on fish-eyecamera panoramic imaging. The main contents of this paper are listed as follows:(1) As the traditional parking assist device only has a single camera, resulting in alimited coverage area and the presence of blind spot. In order to solve the problem, wepropose a method of parking assist system based on the surrounding top-view image from thefusion image. First, four fisheye cameras are fixed around the vehicle to capture images, andthen, the front and rear video images with the perspective effect are transformed into theoverlooking effect by the overlooking perspective transform, and surrounding top-view imageis generated by image mosaic. In this paper, four fisheye cameras are fixed around the vehicleto capture images, expanding the parking horizons. The cameras on the left and right side ofthe vehicle is set to shoot the ground vertically. This saves the time of the image conversion.(2) In order to solve the problems of wide-angle fisheye image distortion, the derivationof camera model is introduced detailed. Based on the analysis fisheye image distortioncharacteristics, camera is calibrated to obtain the parameters and removed the fish-eyedistortion, then the virtual bird-view point position was set in order to transform images intobird-view by using homography matrix, then we project them into one common plane.(3) Based on the larger the fish-eye lens radial distance, the greater the calibration error,due to a large span between each camera, resulting in the problem that the deformation ofmerged area is too large, we propose a method for image registration based on the virtualtemplate. The method for image registration based on the virtual template can significantlyreduce the need for the number of registration feature points and the time of registration,improve processing speed, strengthen immunity and the accuracy of the registration method. Based on the analysis of the fish-eye camera image fusion splicing, we propose to selectpixels from the center of the lens and then using the weighted average fusion. This approachsolves the problem of visual consistency and ensures the quality of surrounding top-viewimage fusion.(4) We implement the parking assist system based on a panoramic imaging in theWindows7system with Visual Studio2010. The experimental results show that the proposedalgorithm has better effectiveness and reliability.