Image stitching - why does the pipeline include 2 times resizing?
Hi all!
I have been working on a project involving image stitching of aerial photography. The stitching pipeline that is given in the documentation of OpenCV I actually encountered many different books and papers and frankly it makes perfect sense (http://docs.opencv.org/modules/stitching/doc/introduction.html). Except for one thing. In the two stages presented there (image acquisition being the first out of three but no point including it there) - registration and composition - I encounter resizing first to a medium and then to low resolution. Can someone explain to me why that is? Does the resizing in the registration stage has to do anything with the feature extraction? The only thing that makes sense to me in all this is that we obviously need the same resolution for all images in an image stitching. Another reason for the additional resizing this time in the composition stage is the computation of masks, which are then applied on the high resolution images that we give as input at the very beginning.
Thanks a lot for your help!
PS: Also with resolution it is obviously meant the number of pixels (since resizing is used in the stitching example), which is somewhat controversial since resolution per definition also depends on the size of each pixel and not only on their numbers as it defines the amount of detail in an image.
