Add paper pdf, update README.md

README.md

@@ -5,6 +5,12 @@
 Interactive user interface that visualizes the distortions that an image block from
 the fisheye domain experiences in the perspective domain and vice versa.
 
+## Paper
+
+We provide a pdf of the corresponding paper presented at VCIP 2020 [here](paper.pdf).
+
+DOI: [10.1109/VCIP49819.2020.9301754](10.1109/VCIP49819.2020.9301754)
+
 ## Setup
 
 Download or clone this repository and enter the main folder. Python 3 is required to