"""
Copyright 2017-2018 Fizyr (https://fizyr.com)
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""
from .anchors import compute_overlap
from .visualization import draw_detections, draw_annotations
import tensorflow as tf
import numpy as np
import os
import time
import cv2
import progressbar
assert(callable(progressbar.progressbar)), "Using wrong progressbar module, install 'progressbar2' instead."
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 _get_detections(generator, model, score_threshold=0.05, max_detections=100, save_path=None):
""" Get the detections from the model using the generator.
The result is a list of lists such that the size is:
all_detections[num_images][num_classes] = detections[num_detections, 4 + num_classes]
# Arguments
generator : The generator used to run images through the model.
model : The model to run on the images.
score_threshold : The score confidence threshold to use.
max_detections : The maximum number of detections to use per image.
save_path : The path to save the images with visualized detections to.
# Returns
A list of lists containing the detections for each image in the generator.
"""
all_detections = [[None for i in range(generator.num_classes()) if generator.has_label(i)] for j in range(generator.size())]
all_inferences = [None for i in range(generator.size())]
for i in progressbar.progressbar(range(generator.size()), prefix='Running network: '):
raw_image = generator.load_image(i)
image = generator.preprocess_image(raw_image.copy())
image, scale = generator.resize_image(image)
if tf.keras.backend.image_data_format() == 'channels_first':
image = image.transpose((2, 0, 1))
# run network
start = time.time()
boxes, scores, labels = model.predict(np.expand_dims(image, axis=0))[:3]
inference_time = time.time() - start
# correct boxes for image scale
boxes /= scale
# select indices which have a score above the threshold
indices = np.where(scores[0, :] > score_threshold)[0]
# select those scores
scores = scores[0][indices]
# find the order with which to sort the scores
scores_sort = np.argsort(-scores)[:max_detections]
# select detections
image_boxes = boxes[0, indices[scores_sort], :]
image_scores = scores[scores_sort]
image_labels = labels[0, indices[scores_sort]]
image_detections = np.concatenate([image_boxes, np.expand_dims(image_scores, axis=1), np.expand_dims(image_labels, axis=1)], axis=1)
if save_path is not None:
draw_annotations(raw_image, generator.load_annotations(i), label_to_name=generator.label_to_name)
draw_detections(raw_image, image_boxes, image_scores, image_labels, label_to_name=generator.label_to_name, score_threshold=score_threshold)
cv2.imwrite(os.path.join(save_path, '{}.png'.format(i)), raw_image)
# copy detections to all_detections
for label in range(generator.num_classes()):
if not generator.has_label(label):
continue
all_detections[i][label] = image_detections[image_detections[:, -1] == label, :-1]
all_inferences[i] = inference_time
return all_detections, all_inferences
def _get_annotations(generator):
""" Get the ground truth annotations from the generator.
The result is a list of lists such that the size is:
all_detections[num_images][num_classes] = annotations[num_detections, 5]
# Arguments
generator : The generator used to retrieve ground truth annotations.
# Returns
A list of lists containing the annotations for each image in the generator.
"""
all_annotations = [[None for i in range(generator.num_classes())] for j in range(generator.size())]
for i in progressbar.progressbar(range(generator.size()), prefix='Parsing annotations: '):
# load the annotations
annotations = generator.load_annotations(i)
# copy detections to all_annotations
for label in range(generator.num_classes()):
if not generator.has_label(label):
continue
all_annotations[i][label] = annotations['bboxes'][annotations['labels'] == label, :].copy()
return all_annotations
def print_results(generator, average_precisions, inference_time):
""" Print evaluation results.
# Arguments
generator : The generator that represents the dataset to evaluate.
average_precision : Average precisions per label.
inference_time : Total time spent on inference.
"""
total_instances = []
precisions = []
for label, (average_precision, num_annotations) in average_precisions.items():
print('{:.0f} instances of class'.format(num_annotations),
generator.label_to_name(label), 'with average precision: {:.4f}'.format(average_precision))
total_instances.append(num_annotations)
precisions.append(average_precision)
if sum(total_instances) == 0:
print('No test instances found.')
return
print('Inference time for {:.0f} images: {:.4f}'.format(generator.size(), inference_time))
print('mAP using the weighted average of precisions among classes: {:.4f}'.format(sum([a * b for a, b in zip(total_instances, precisions)]) / sum(total_instances)))
print('mAP: {:.4f}'.format(sum(precisions) / sum(x > 0 for x in total_instances)))
def evaluate(
generator,
model,
iou_threshold=0.5,
score_threshold=0.05,
max_detections=100,
save_path=None
):
""" Evaluate a given dataset using a given model.
# Arguments
generator : The generator that represents the dataset to evaluate.
model : The model to evaluate.
iou_threshold : The threshold used to consider when a detection is positive or negative.
score_threshold : The score confidence threshold to use for detections.
max_detections : The maximum number of detections to use per image.
save_path : The path to save images with visualized detections to.
# Returns
A dict mapping class names to mAP scores.
"""
# gather all detections and annotations
all_detections, all_inferences = _get_detections(generator, model, score_threshold=score_threshold, max_detections=max_detections, save_path=save_path)
all_annotations = _get_annotations(generator)
average_precisions = {}
# all_detections = pickle.load(open('all_detections.pkl', 'rb'))
# all_annotations = pickle.load(open('all_annotations.pkl', 'rb'))
# pickle.dump(all_detections, open('all_detections.pkl', 'wb'))
# pickle.dump(all_annotations, open('all_annotations.pkl', 'wb'))
# process detections and annotations
for label in range(generator.num_classes()):
if not generator.has_label(label):
continue
false_positives = np.zeros((0,))
true_positives = np.zeros((0,))
scores = np.zeros((0,))
num_annotations = 0.0
for i in range(generator.size()):
detections = all_detections[i][label]
annotations = all_annotations[i][label]
num_annotations += annotations.shape[0]
detected_annotations = []
for d in detections:
scores = np.append(scores, d[4])
if annotations.shape[0] == 0:
false_positives = np.append(false_positives, 1)
true_positives = np.append(true_positives, 0)
continue
overlaps = compute_overlap(np.expand_dims(d, axis=0), annotations)
assigned_annotation = np.argmax(overlaps, axis=1)
max_overlap = overlaps[0, assigned_annotation]
if max_overlap >= iou_threshold and assigned_annotation not in detected_annotations:
false_positives = np.append(false_positives, 0)
true_positives = np.append(true_positives, 1)
detected_annotations.append(assigned_annotation)
else:
false_positives = np.append(false_positives, 1)
true_positives = np.append(true_positives, 0)
# no annotations -> AP for this class is 0 (is this correct?)
if num_annotations == 0:
average_precisions[label] = 0, 0
continue
# sort by score
indices = np.argsort(-scores)
false_positives = false_positives[indices]
true_positives = true_positives[indices]
# compute false positives and true positives
false_positives = np.cumsum(false_positives)
true_positives = np.cumsum(true_positives)
# compute recall and precision
recall = true_positives / num_annotations
precision = true_positives / np.maximum(true_positives + false_positives, np.finfo(np.float64).eps)
# compute average precision
average_precision = _compute_ap(recall, precision)
average_precisions[label] = average_precision, num_annotations
inference_time = np.sum(all_inferences) / generator.size()
print_results(generator, average_precisions, inference_time)
