Research On The Key Technology Of Panoramic Imaging Based On Ultrawide Angle Fisheye

The use of fisheye lens images for panoramic image stitching has been more and more researched and widely used.Compared with the perspective images,the fisheye lens has a larger viewing angle,so it can reduce the number of images of acquisition,which greatly shorten the process of image processing and improve the efficiency of stitching.But the distortion effect caused by special optical effect makes the image registration difficult to be carried out.The determination of the relative positional relationship between the fish-eye lens cameras has been an important factor affecting the effect of fish-eye images stitching into panoramic images.In order to get the internal and external parameters of camera,ordinary camera can be calibrated for single camera and then determine the relative position by external parameters.However,the fisheye lens used in this paper has a visual angle of more than 220 °.The traditional method can not calibrate the external parameters,so a panoramic image generation method based on the equiangular rectangular projection method and the spherical matching method is proposed.In this paper,the method of stitching fisheye images using two wide-angle-of-view fisheye images is taken with two "back-to-back" fixed-position cameras.Due to the distortion(mainly barrel distortion)effect of the existence,resulting in the relative figure in the same scene with different characteristics.According to the imaging model of fish-eye camera and the feature of map projection,this paper proposes the projection of fish-eye image by equiangular rectangle projection.The image is rotated 90 ° around the X axis in the camera coordinate system.After these two operations,fisheye images around the image can be a unified correction.For the case of exposure differences,this paper uses the linear weighted fusion method to deal with the better results.