Object Detection Evaluation
• Match the object “book1.pgm” to each of the images
“Img0[i].pgm”, where [i]=1...10.
• What is a good threshold for the number of feature matches,
that can classify whether the object is present in an image?
• You want a value that the maximizes the true positive rate and
minimizes the false positive rate.
– True positive rate: The number of correct detections of the object
divided by the number of times that it was really there.
– False positive: The number of false detections of the object divided
by the number of times that it was not really there.
from: “Computer Vision: Algorithms and
Applications”, by Richard Szeliski
Image Alignment
• Images river1.jpg,
river2.jpg in vlfeat’s data
folder
• Images roofs1.jpg,
roofs2.jpg in vlfeat’s data
folder
• Images floor1.jpg,
floor2.jpg on course
website