forked from experiencor/keras-yolo2
/
utils.py
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/
utils.py
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import numpy as np
import os
import xml.etree.ElementTree as ET
import tensorflow as tf
import copy
import cv2
class BoundBox:
def __init__(self, xmin, ymin, xmax, ymax, c = None, classes = None):
self.xmin = xmin
self.ymin = ymin
self.xmax = xmax
self.ymax = ymax
self.c = c
self.classes = classes
self.label = -1
self.score = -1
def get_label(self):
if self.label == -1:
self.label = np.argmax(self.classes)
return self.label
def get_score(self):
if self.score == -1:
self.score = self.classes[self.get_label()]
return self.score
class WeightReader:
def __init__(self, weight_file):
self.offset = 4
self.all_weights = np.fromfile(weight_file, dtype='float32')
def read_bytes(self, size):
self.offset = self.offset + size
return self.all_weights[self.offset-size:self.offset]
def reset(self):
self.offset = 4
def bbox_iou(box1, box2):
intersect_w = _interval_overlap([box1.xmin, box1.xmax], [box2.xmin, box2.xmax])
intersect_h = _interval_overlap([box1.ymin, box1.ymax], [box2.ymin, box2.ymax])
intersect = intersect_w * intersect_h
w1, h1 = box1.xmax-box1.xmin, box1.ymax-box1.ymin
w2, h2 = box2.xmax-box2.xmin, box2.ymax-box2.ymin
union = w1*h1 + w2*h2 - intersect
return float(intersect) / union
def draw_boxes(image, boxes, labels):
image_h, image_w, _ = image.shape
for box in boxes:
xmin = int(box.xmin*image_w)
ymin = int(box.ymin*image_h)
xmax = int(box.xmax*image_w)
ymax = int(box.ymax*image_h)
cv2.rectangle(image, (xmin,ymin), (xmax,ymax), (0,255,0), 3)
cv2.putText(image,
labels[box.get_label()] + ' ' + str(box.get_score()),
(xmin, ymin - 13),
cv2.FONT_HERSHEY_SIMPLEX,
1e-3 * image_h,
(0,255,0), 2)
return image
def decode_netout(netout, anchors, nb_class, obj_threshold=0.3, nms_threshold=0.3):
grid_h, grid_w, nb_box = netout.shape[:3]
boxes = []
# decode the output by the network
netout[..., 4] = _sigmoid(netout[..., 4])
netout[..., 5:] = netout[..., 4][..., np.newaxis] * _softmax(netout[..., 5:])
netout[..., 5:] *= netout[..., 5:] > obj_threshold
for row in range(grid_h):
for col in range(grid_w):
for b in range(nb_box):
# from 4th element onwards are confidence and class classes
classes = netout[row,col,b,5:]
if np.sum(classes) > 0:
# first 4 elements are x, y, w, and h
x, y, w, h = netout[row,col,b,:4]
x = (col + _sigmoid(x)) / grid_w # center position, unit: image width
y = (row + _sigmoid(y)) / grid_h # center position, unit: image height
w = anchors[2 * b + 0] * np.exp(w) / grid_w # unit: image width
h = anchors[2 * b + 1] * np.exp(h) / grid_h # unit: image height
confidence = netout[row,col,b,4]
box = BoundBox(x-w/2, y-h/2, x+w/2, y+h/2, confidence, classes)
boxes.append(box)
# suppress non-maximal boxes
for c in range(nb_class):
sorted_indices = list(reversed(np.argsort([box.classes[c] for box in boxes])))
for i in range(len(sorted_indices)):
index_i = sorted_indices[i]
if boxes[index_i].classes[c] == 0:
continue
else:
for j in range(i+1, len(sorted_indices)):
index_j = sorted_indices[j]
if bbox_iou(boxes[index_i], boxes[index_j]) >= nms_threshold:
boxes[index_j].classes[c] = 0
# remove the boxes which are less likely than a obj_threshold
boxes = [box for box in boxes if box.get_score() > obj_threshold]
return boxes
def compute_overlap(a, b):
"""
Code originally from https://github.com/rbgirshick/py-faster-rcnn.
Parameters
----------
a: (N, 4) ndarray of float
b: (K, 4) ndarray of float
Returns
-------
overlaps: (N, K) ndarray of overlap between boxes and query_boxes
"""
area = (b[:, 2] - b[:, 0]) * (b[:, 3] - b[:, 1])
iw = np.minimum(np.expand_dims(a[:, 2], axis=1), b[:, 2]) - np.maximum(np.expand_dims(a[:, 0], 1), b[:, 0])
ih = np.minimum(np.expand_dims(a[:, 3], axis=1), b[:, 3]) - np.maximum(np.expand_dims(a[:, 1], 1), b[:, 1])
iw = np.maximum(iw, 0)
ih = np.maximum(ih, 0)
ua = np.expand_dims((a[:, 2] - a[:, 0]) * (a[:, 3] - a[:, 1]), axis=1) + area - iw * ih
ua = np.maximum(ua, np.finfo(float).eps)
intersection = iw * ih
return intersection / ua
def compute_ap(recall, precision):
""" Compute the average precision, given the recall and precision curves.
Code originally from https://github.com/rbgirshick/py-faster-rcnn.
# Arguments
recall: The recall curve (list).
precision: The precision curve (list).
# Returns
The average precision as computed in py-faster-rcnn.
"""
# correct AP calculation
# first append sentinel values at the end
mrec = np.concatenate(([0.], recall, [1.]))
mpre = np.concatenate(([0.], precision, [0.]))
# compute the precision envelope
for i in range(mpre.size - 1, 0, -1):
mpre[i - 1] = np.maximum(mpre[i - 1], mpre[i])
# to calculate area under PR curve, look for points
# where X axis (recall) changes value
i = np.where(mrec[1:] != mrec[:-1])[0]
# and sum (\Delta recall) * prec
ap = np.sum((mrec[i + 1] - mrec[i]) * mpre[i + 1])
return ap
def _interval_overlap(interval_a, interval_b):
x1, x2 = interval_a
x3, x4 = interval_b
if x3 < x1:
if x4 < x1:
return 0
else:
return min(x2,x4) - x1
else:
if x2 < x3:
return 0
else:
return min(x2,x4) - x3
def _sigmoid(x):
return 1. / (1. + np.exp(-x))
def _softmax(x, axis=-1, t=-100.):
x = x - np.max(x)
if np.min(x) < t:
x = x/np.min(x)*t
e_x = np.exp(x)
return e_x / e_x.sum(axis, keepdims=True)