For example, an Intelligent Drone that maps the 3D of Interior and Exterior of any object or structure for example… Building, House, Tree, Statue or any thing… just brain storming. … need to choose realizable…
Go for MATLAB and MATLAB based Image Processing Projects, for starting. Also, side by side start learning Classificication algorihms, like K-Means, Logisitc Regression, State Vector Machines, Neural Networks etc.
You can use OpenCV to implement image processing algorithms. You can start with some basic things like Noise Removal, Image enhancement, Template matching, Feature Detection. Source codes are available in internet using different algorithms. You can take one of them and run with your sample image. Then you will be able to find which feature is needed for your application. For example if you want to track human eye, you can use feature detection.
Lots of materials available in Youtube : https://www.youtube.com/results?search_query=opencv+tutorial
You can also use OpenCV on a Raspberry Pi. By which you can make a robot tracking something and so on. https://www.youtube.com/watch?v=6j-Wy9j0TCs