  In this paper, we propose a panorama stitching algorithm based on asymmetric
bidirectional optical flow. This algorithm expects multiple photos captured by
fisheye lens cameras as input, and then, through the proposed algorithm, these
photos can be merged into a high-quality 360-degree spherical panoramic image.
For photos taken from a distant perspective, the parallax among them is
relatively small, and the obtained panoramic image can be nearly seamless and
undistorted. For photos taken from a close perspective or with a relatively
large parallax, a seamless though partially distorted panoramic image can also
be obtained. Besides, with the help of Graphics Processing Unit (GPU), this
algorithm can complete the whole stitching process at a very fast speed:
typically, it only takes less than 30s to obtain a panoramic image of
9000-by-4000 pixels, which means our panorama stitching algorithm is of high
value in many real-time applications. Our code is available at
https://github.com/MungoMeng/Panorama-OpticalFlow.
