Hugin is an easy to use cross-platform panoramic imaging toolchain based on Panorama Tools. With Hugin you can assemble a mosaic of photographs into a complete impressive panorama, stitch any series of overlapping pictures and much more.i
Hugin vs PTgui opinions
Fast Panorama Stitcher and Blender, implemented in SIMD-Math.
PTStitcherNG reads and transforms any number and type of input images, and combines them into one seamless panoramic image with larger field-of-view. Given enough input images, full spherical 360x180 degree views can.