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Machine-Learning-Collection/ML/Pytorch/object_detection/metrics/nms.py
Aladdin Persson 65b8c80495 Initial commit
2021-01-30 21:49:15 +01:00

43 lines
1.3 KiB
Python

import torch
from iou import intersection_over_union
def nms(bboxes, iou_threshold, threshold, box_format="corners"):
"""
Does Non Max Suppression given bboxes
Parameters:
bboxes (list): list of lists containing all bboxes with each bboxes
specified as [class_pred, prob_score, x1, y1, x2, y2]
iou_threshold (float): threshold where predicted bboxes is correct
threshold (float): threshold to remove predicted bboxes (independent of IoU)
box_format (str): "midpoint" or "corners" used to specify bboxes
Returns:
list: bboxes after performing NMS given a specific IoU threshold
"""
assert type(bboxes) == list
bboxes = [box for box in bboxes if box[1] > threshold]
bboxes = sorted(bboxes, key=lambda x: x[1], reverse=True)
bboxes_after_nms = []
while bboxes:
chosen_box = bboxes.pop(0)
bboxes = [
box
for box in bboxes
if box[0] != chosen_box[0]
or intersection_over_union(
torch.tensor(chosen_box[2:]),
torch.tensor(box[2:]),
box_format=box_format,
)
< iou_threshold
]
bboxes_after_nms.append(chosen_box)
return bboxes_after_nms