I have a data mining assignment where I make a content-based image retrieval system. I have 20 images of 5 animals. So in total 100 images.
My code returns the 10 most relevant images to an input image.
Now I need to evaluate the performance of my system with a Precision-Recall curve. However, I do not understand the concept of a Precision-Recall curve.
Let's say my system returns 10 most relevant images of a gorilla, but only 4 of them are gorillas. The other 6 images returned are other animals'.
Now my precision is
4/10 = 0.4
and my recall is
4/20 = 0.2
So I only have a point
<0.2,0.4> not a curve.
How do I have a curve?
By changing the number of images returned (which is fixed = 10 in my case) ?
Any help would be appreciated,