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Add script to evaluate face recognition by LFW (#72)
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from __future__ import absolute_import | ||
from __future__ import division | ||
from __future__ import print_function | ||
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import os | ||
import numpy as np | ||
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from sklearn.model_selection import KFold | ||
from scipy import interpolate | ||
import sklearn | ||
from sklearn.decomposition import PCA | ||
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import cv2 as cv | ||
from tqdm import tqdm | ||
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def calculate_roc(thresholds, | ||
embeddings1, | ||
embeddings2, | ||
actual_issame, | ||
nrof_folds=10, | ||
pca=0): | ||
assert (embeddings1.shape[0] == embeddings2.shape[0]) | ||
assert (embeddings1.shape[1] == embeddings2.shape[1]) | ||
nrof_pairs = min(len(actual_issame), embeddings1.shape[0]) | ||
nrof_thresholds = len(thresholds) | ||
k_fold = KFold(n_splits=nrof_folds, shuffle=False) | ||
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tprs = np.zeros((nrof_folds, nrof_thresholds)) | ||
fprs = np.zeros((nrof_folds, nrof_thresholds)) | ||
accuracy = np.zeros((nrof_folds)) | ||
indices = np.arange(nrof_pairs) | ||
# print('pca', pca) | ||
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if pca == 0: | ||
diff = np.subtract(embeddings1, embeddings2) | ||
dist = np.sum(np.square(diff), 1) | ||
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for fold_idx, (train_set, test_set) in enumerate(k_fold.split(indices)): | ||
# print('train_set', train_set) | ||
# print('test_set', test_set) | ||
if pca > 0: | ||
print('doing pca on', fold_idx) | ||
embed1_train = embeddings1[train_set] | ||
embed2_train = embeddings2[train_set] | ||
_embed_train = np.concatenate((embed1_train, embed2_train), axis=0) | ||
# print(_embed_train.shape) | ||
pca_model = PCA(n_components=pca) | ||
pca_model.fit(_embed_train) | ||
embed1 = pca_model.transform(embeddings1) | ||
embed2 = pca_model.transform(embeddings2) | ||
embed1 = sklearn.preprocessing.normalize(embed1) | ||
embed2 = sklearn.preprocessing.normalize(embed2) | ||
# print(embed1.shape, embed2.shape) | ||
diff = np.subtract(embed1, embed2) | ||
dist = np.sum(np.square(diff), 1) | ||
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# Find the best threshold for the fold | ||
acc_train = np.zeros((nrof_thresholds)) | ||
for threshold_idx, threshold in enumerate(thresholds): | ||
_, _, acc_train[threshold_idx] = calculate_accuracy( | ||
threshold, dist[train_set], actual_issame[train_set]) | ||
best_threshold_index = np.argmax(acc_train) | ||
for threshold_idx, threshold in enumerate(thresholds): | ||
tprs[fold_idx, | ||
threshold_idx], fprs[fold_idx, | ||
threshold_idx], _ = calculate_accuracy( | ||
threshold, dist[test_set], | ||
actual_issame[test_set]) | ||
_, _, accuracy[fold_idx] = calculate_accuracy( | ||
thresholds[best_threshold_index], dist[test_set], | ||
actual_issame[test_set]) | ||
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tpr = np.mean(tprs, 0) | ||
fpr = np.mean(fprs, 0) | ||
return tpr, fpr, accuracy | ||
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def calculate_accuracy(threshold, dist, actual_issame): | ||
predict_issame = np.less(dist, threshold) | ||
tp = np.sum(np.logical_and(predict_issame, actual_issame)) | ||
fp = np.sum(np.logical_and(predict_issame, np.logical_not(actual_issame))) | ||
tn = np.sum( | ||
np.logical_and(np.logical_not(predict_issame), | ||
np.logical_not(actual_issame))) | ||
fn = np.sum(np.logical_and(np.logical_not(predict_issame), actual_issame)) | ||
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tpr = 0 if (tp + fn == 0) else float(tp) / float(tp + fn) | ||
fpr = 0 if (fp + tn == 0) else float(fp) / float(fp + tn) | ||
acc = float(tp + tn) / dist.size | ||
return tpr, fpr, acc | ||
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def calculate_val(thresholds, | ||
embeddings1, | ||
embeddings2, | ||
actual_issame, | ||
far_target, | ||
nrof_folds=10): | ||
assert (embeddings1.shape[0] == embeddings2.shape[0]) | ||
assert (embeddings1.shape[1] == embeddings2.shape[1]) | ||
nrof_pairs = min(len(actual_issame), embeddings1.shape[0]) | ||
nrof_thresholds = len(thresholds) | ||
k_fold = KFold(n_splits=nrof_folds, shuffle=False) | ||
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val = np.zeros(nrof_folds) | ||
far = np.zeros(nrof_folds) | ||
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diff = np.subtract(embeddings1, embeddings2) | ||
dist = np.sum(np.square(diff), 1) | ||
indices = np.arange(nrof_pairs) | ||
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for fold_idx, (train_set, test_set) in enumerate(k_fold.split(indices)): | ||
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# Find the threshold that gives FAR = far_target | ||
far_train = np.zeros(nrof_thresholds) | ||
for threshold_idx, threshold in enumerate(thresholds): | ||
_, far_train[threshold_idx] = calculate_val_far( | ||
threshold, dist[train_set], actual_issame[train_set]) | ||
if np.max(far_train) >= far_target: | ||
f = interpolate.interp1d(far_train, thresholds, kind='slinear') | ||
threshold = f(far_target) | ||
else: | ||
threshold = 0.0 | ||
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val[fold_idx], far[fold_idx] = calculate_val_far( | ||
threshold, dist[test_set], actual_issame[test_set]) | ||
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val_mean = np.mean(val) | ||
far_mean = np.mean(far) | ||
val_std = np.std(val) | ||
return val_mean, val_std, far_mean | ||
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def calculate_val_far(threshold, dist, actual_issame): | ||
predict_issame = np.less(dist, threshold) | ||
true_accept = np.sum(np.logical_and(predict_issame, actual_issame)) | ||
false_accept = np.sum( | ||
np.logical_and(predict_issame, np.logical_not(actual_issame))) | ||
n_same = np.sum(actual_issame) | ||
n_diff = np.sum(np.logical_not(actual_issame)) | ||
val = float(true_accept) / float(n_same) | ||
far = float(false_accept) / float(n_diff) | ||
return val, far | ||
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def evaluate(embeddings, actual_issame, nrof_folds=10, pca=0): | ||
# Calculate evaluation metrics | ||
thresholds = np.arange(0, 4, 0.01) | ||
embeddings1 = embeddings[0::2] | ||
embeddings2 = embeddings[1::2] | ||
tpr, fpr, accuracy = calculate_roc(thresholds, | ||
embeddings1, | ||
embeddings2, | ||
np.asarray(actual_issame), | ||
nrof_folds=nrof_folds, | ||
pca=pca) | ||
thresholds = np.arange(0, 4, 0.001) | ||
val, val_std, far = calculate_val(thresholds, | ||
embeddings1, | ||
embeddings2, | ||
np.asarray(actual_issame), | ||
1e-3, | ||
nrof_folds=nrof_folds) | ||
return tpr, fpr, accuracy, val, val_std, far | ||
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class LFW: | ||
def __init__(self, root, target_size=250): | ||
self.LFW_IMAGE_SIZE = 250 | ||
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self.lfw_root = root | ||
self.target_size = target_size | ||
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self.lfw_pairs_path = os.path.join(self.lfw_root, 'view2/pairs.txt') | ||
self.image_path_pattern = os.path.join(self.lfw_root, 'lfw', '{person_name}', '{image_name}') | ||
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self.lfw_image_paths, self.id_list = self.load_pairs() | ||
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@property | ||
def name(self): | ||
return 'LFW' | ||
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def __len__(self): | ||
return len(self.lfw_image_paths) | ||
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@property | ||
def ids(self): | ||
return self.id_list | ||
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def load_pairs(self): | ||
image_paths = [] | ||
id_list = [] | ||
with open(self.lfw_pairs_path, 'r') as f: | ||
for line in f.readlines()[1:]: | ||
line = line.strip().split() | ||
if len(line) == 3: | ||
person_name = line[0] | ||
image1_name = '{}_{:04d}.jpg'.format(person_name, int(line[1])) | ||
image2_name = '{}_{:04d}.jpg'.format(person_name, int(line[2])) | ||
image_paths += [ | ||
self.image_path_pattern.format(person_name=person_name, image_name=image1_name), | ||
self.image_path_pattern.format(person_name=person_name, image_name=image2_name) | ||
] | ||
id_list.append(True) | ||
elif len(line) == 4: | ||
person1_name = line[0] | ||
image1_name = '{}_{:04d}.jpg'.format(person1_name, int(line[1])) | ||
person2_name = line[2] | ||
image2_name = '{}_{:04d}.jpg'.format(person2_name, int(line[3])) | ||
image_paths += [ | ||
self.image_path_pattern.format(person_name=person1_name, image_name=image1_name), | ||
self.image_path_pattern.format(person_name=person2_name, image_name=image2_name) | ||
] | ||
id_list.append(False) | ||
return image_paths, id_list | ||
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def __getitem__(self, key): | ||
img = cv.imread(self.lfw_image_paths[key]) | ||
if self.target_size != self.LFW_IMAGE_SIZE: | ||
img = cv.resize(img, (self.target_size, self.target_size)) | ||
return img | ||
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def eval(self, model): | ||
ids = self.ids | ||
embeddings = np.zeros(shape=(len(self), 128)) | ||
face_bboxes = np.load("./datasets/lfw_face_bboxes.npy") | ||
for idx, img in tqdm(enumerate(self), desc="Evaluating {} with {} val set".format(model.name, self.name)): | ||
embedding = model.infer(img, face_bboxes[idx]) | ||
embeddings[idx] = embedding | ||
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embeddings = sklearn.preprocessing.normalize(embeddings) | ||
self.tpr, self.fpr, self.acc, self.val, self.std, self.far = evaluate(embeddings, ids, nrof_folds=10) | ||
self.acc, self.std = np.mean(self.acc), np.std(self.acc) | ||
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def print_result(self): | ||
print("==================== Results ====================") | ||
print("Average Accuracy: {:.4f}".format(self.acc)) | ||
print("=================================================") |
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