WHY ARE THERE FLOATING HEADS IN THE IMAGE?
This is a problem that often occurs in panoramic photography when the scene that has been captured contains objects that have moved between frames, like people or cars, clouds, waves, or boats on a river. Since panoramic frames overlap the object may be in one frame and not the other.
Advanced panorama software such as Autopano Giga use anti-ghosting algorithms when they blend the images. It gets rid of a lot of the ghosting but not all of it.
Some panorama software simply defines a rectangular 'blend area' and merges the pixels from the two images inside the blend area. This method is very crude by today's standards and can cause some extreme ghosting problems, where the slightest movement in the overlap zone results in transparent double images in the finished panoramic photo.
Other, smarter photo stitching software packages calculate a 'blend path' which is like a meandering line where the two images can be joined together with the least possible variations from one side of the line to the other. In most cases the user can adjust the blend path to improve the result if the software doesn't quite get it right.
If the file size isn’t too big the stitched image can be retouched with Photoshop via the healing brush or clone stamp tools.