Images of the Russian Empire:Colorizing the Prokudin-Gorskii photo collection
Nisheeth Sharma
So I decided to use a system where matching between two images is done by first generating
all edges of the image using a sobel filter. Then I use a simple sum of square difference algorithm
to generate the match between the edge images. This displacement is then used on the actual color
segments. I find that this method is slightly more accurate while matching than not using the edge
filter. Matching is only performed on the inner 64% of the image by area (I ignore the top and side 10%)
so that the artifacts on the edges do not significantly affect the image. Lastly, all matching is done by
first halving the image until the resultant is less than 250px in height and width. I then search upwards till
I reach the original image.
Smaller images
Larger images
This picture align pretty badly . I think this is because background is such that when the sobel filter runs alot of the edges are just parallel lines. Thus the page tends to align well with the current orientation and the correct one. The same goes for the older gentleman's beard