During
object detection ,
When the
image has more than one anchor box after filtering by thresholding over the classes scores , we use non-max suppression to get one anchor box for object detection.
Non-max suppression uses intersection over union.
Non-max suppression uses intersection over union.
Intersection over union calculates the intersection area of any two boxes by area of union of two boxes.
Here we have considered the coordinates of each box which are diagonal like top left and bottom right
Here we have considered the coordinates of each box which are diagonal like top left and bottom right
Our naming
conventions here for each box (x1,y1) –
top left and (x2,y2) – bottom right.
Now for two
boxes to calculate the intersection need to find the maximum for top left and minimum
of bottom right.
X1_inter =
max(box1(x1), box2(x1))
Y1_inter =
max(box1(y1), box2(y1))
X2_inter = min(box1(x2),
box2(x2))
Y2_inter =
min(box1(y2), box2(y2))
Here is the
code to implement iou:
