Many panoramic cameras, such as Mijia Panoramic Camera, consist of 2 fisheye cameras.
The resulting file is a fisheye lens image, as shown below.
If you need to create a panorama from a fish-eye image, you need to install professional software, such as PTGui.
Occasionally I found a related project on Github dualfisheye2equirectangular which is specially designed to meet such a need.
Follow the README operation can successfully generate the following panorama original image
The resulting original image will overlap on the other side of the two fisheye seams because a fisheye lens greater than 180 degrees was used.