def single_batch_nms(candidate_boxes):
y_mask = candidate_boxes[..., 4] >= self.score_threshold
candidate_boxes = candidate_boxes[y_mask]
outputs = torch.zeros((self.max_detection + 1, candidate_boxes.size(-1)))
indices = []
updates = []
count = 0
while candidate_boxes.size(0) > 0 and count < self.max_detection:
best_idx = torch.argmax(candidate_boxes[..., 4], dim=0)
best_box = candidate_boxes[best_idx]
indices.append([count] * candidate_boxes.size(-1))
updates.append(best_box)
count += 1
candidate_boxes = torch.cat(
(candidate_boxes[0:best_idx], candidate_boxes[best_idx + 1:candidate_boxes.size(0)]), dim=0)
iou = broadcast_iou(best_box[0:4], candidate_boxes[..., 0:4])
iou_mask = iou <= self.iou_threshold
candidate_boxes = candidate_boxes[iou_mask]
if count > 0:
count_index = [[self.max_detection] * candidate_boxes.size(-1)]
count_updates = [torch.zeros(candidate_boxes.size(-1)).fill_(count)]
indices = torch.cat((torch.tensor(indices), torch.tensor(count_index)), dim=0)
updates = torch.cat((torch.stack(updates).cuda(), torch.stack(count_updates).cuda()), dim=0)
outputs = outputs.cuda().scatter_(0, indices.cuda(), updates)
return outputs
def calc_ignore_mask(self, true_box, pred_box, true_obj):
# (batch, 13, 13, 3, 4)
true_box_shape = true_box.shape
pred_box_shape = pred_box.shape
true_box = torch.reshape(true_box, [true_box_shape[0], -1, 4])
true_box = torch.sort(true_box, dim=1, descending=True).values
# true_box = true_box[:, 0:100, :]
# pred_box, true_box shape : (batch, 507, 4)
pred_box = torch.reshape(pred_box, [pred_box_shape[0], -1, 4])
# (batch, 507. 507)
iou = broadcast_iou(pred_box, true_box)
# tensorflow 코드에서는 reduce_max를 해야하는데 여기선 필요 없나?
# https://github.com/ethanyanjiali/deep-vision/blob/master/YOLO/tensorflow/yolov3.py#L462
# best_iou = torch.max(iou, dim=-1).values
best_iou = iou
best_iou = torch.reshape(best_iou, [
pred_box_shape[0], pred_box_shape[1], pred_box_shape[2],
pred_box_shape[3]
])
# (batch, 13, 13, 3, 1)
ignore_mask = (best_iou < self.ignore_thresh).float()
ignore_mask = torch.unsqueeze(ignore_mask, dim=-1)
return ignore_mask
def yolo_loss(y_true, y_pred):
# 1. transform all pred outputs
# y_pred: (batch_size, grid, grid, anchors, (x, y, w, h, obj, ...cls))
pred_box, pred_obj, pred_class, pred_xywh = yolo_boxes(
y_pred, anchors, classes)
pred_xy = pred_xywh[..., 0:2]
pred_wh = pred_xywh[..., 2:4]
# 2. transform all true outputs
# y_true: (batch_size, grid, grid, anchors, (x1, y1, x2, y2, obj, cls))
true_box, true_obj, true_class_idx = tf.split(y_true, (4, 1, 1),
axis=-1)
true_xy = (true_box[..., 0:2] + true_box[..., 2:4]) / 2
true_wh = true_box[..., 2:4] - true_box[..., 0:2]
# give higher weights to small boxes
box_loss_scale = 2 - true_wh[..., 0] * true_wh[..., 1]
# 3. inverting the pred box equations
grid_size = tf.shape(y_true)[1]
grid = tf.meshgrid(tf.range(grid_size), tf.range(grid_size))
grid = tf.expand_dims(tf.stack(grid, axis=-1), axis=2)
true_xy = true_xy * tf.cast(grid_size, tf.float32) - \
tf.cast(grid, tf.float32)
true_wh = tf.math.log(true_wh / anchors)
true_wh = tf.where(tf.math.is_inf(true_wh), tf.zeros_like(true_wh),
true_wh)
# 4. calculate all masks
obj_mask = tf.squeeze(true_obj, -1)
# ignore false positive when iou is over threshold
best_iou = tf.map_fn(
lambda x: tf.reduce_max(broadcast_iou(
x[0], tf.boolean_mask(x[1], tf.cast(x[2], tf.bool))),
axis=-1), (pred_box, true_box, obj_mask),
tf.float32)
ignore_mask = tf.cast(best_iou < ignore_thresh, tf.float32)
# 5. calculate all losses
xy_loss = obj_mask * box_loss_scale * \
tf.reduce_sum(tf.square(true_xy - pred_xy), axis=-1)
wh_loss = obj_mask * box_loss_scale * \
tf.reduce_sum(tf.square(true_wh - pred_wh), axis=-1)
obj_loss = binary_crossentropy(true_obj, pred_obj)
obj_loss = obj_mask * obj_loss + \
(1 - obj_mask) * ignore_mask * obj_loss
if Config.CLASS_MUTUALLY_EXCLUSIVE is True:
class_loss = obj_mask * sparse_categorical_crossentropy(
true_class_idx, pred_class)
else:
class_loss = obj_mask * binary_crossentropy(
true_class_idx, pred_class)
# 6. sum over (batch, gridx, gridy, anchors) => (batch, 1)
xy_loss = tf.reduce_sum(xy_loss, axis=(1, 2, 3))
wh_loss = tf.reduce_sum(wh_loss, axis=(1, 2, 3))
obj_loss = tf.reduce_sum(obj_loss, axis=(1, 2, 3))
class_loss = tf.reduce_sum(class_loss, axis=(1, 2, 3))
return xy_loss + wh_loss + obj_loss + class_loss
def yoloLoss(y_true, y_pred):
pred_box, pred_obj, pred_class, pred_xywh = yolo_boxes(
y_pred, anchors, class_num)
pred_xy = pred_xywh[..., 0:2] # 取出偏移量
pred_wh = pred_xywh[..., 2:4]
true_box, true_obj, true_class_idx = tf.split(y_true, (4, 1, 1),
axis=-1)
true_xy = (true_box[..., 0:2] + true_box[..., 2:4]) / 2
true_wh = true_box[..., 2:4] - true_box[..., 0:2]
box_loss_scale = 2 - true_wh[..., 0] * true_wh[..., 1]
grid_size = tf.shape(y_true)[1]
grid = tf.meshgrid(tf.range(grid_size), tf.range(grid_size))
grid = tf.expand_dims(tf.stack(grid, axis=-1), axis=2)
true_xy = true_xy * tf.cast(grid_size, tf.float32) - \
tf.cast(grid, tf.float32)
true_wh = tf.math.log(true_wh / anchors)
true_wh = tf.where(tf.math.is_inf(true_wh), tf.zeros_like(true_wh),
true_wh) # 将真实坐标转变为偏移量用于计算loss
obj_mask = tf.squeeze(true_obj, -1)
# ignore false positive when iou is over threshold
best_iou = tf.map_fn(
lambda x: tf.reduce_max(broadcast_iou(
x[0], tf.boolean_mask(x[1], tf.cast(x[2], tf.bool))),
axis=-1), (pred_box, true_box, obj_mask),
tf.float32)
ignore_mask = tf.cast(best_iou < ignore_thresh, tf.float32)
xy_loss = obj_mask * box_loss_scale * \
tf.reduce_sum(tf.square(true_xy - pred_xy), axis=-1)
wh_loss = obj_mask * box_loss_scale * \
tf.reduce_sum(tf.square(true_wh - pred_wh), axis=-1)
obj_loss = binary_crossentropy(true_obj, pred_obj)
obj_loss = obj_mask * obj_loss + \
(1 - obj_mask) * ignore_mask * obj_loss
# TODO: use binary_crossentropy instead
class_loss = obj_mask * sparse_categorical_crossentropy(
true_class_idx, pred_class)
xy_loss = tf.reduce_sum(xy_loss, axis=(1, 2, 3))
wh_loss = tf.reduce_sum(wh_loss, axis=(1, 2, 3))
obj_loss = tf.reduce_sum(obj_loss, axis=(1, 2, 3))
class_loss = tf.reduce_sum(class_loss, axis=(1, 2, 3))
return xy_loss + wh_loss + obj_loss + class_loss
def calc_ignore_mask(self, true_box, pred_box, true_obj):
obj_mask = torch.squeeze(true_obj, dim=-1)
best_iou = []
for x in zip(pred_box, true_box, obj_mask):
mask = x[1][x[2].bool()]
if mask.size(0) is not 0:
best_iou.append(broadcast_iou(x[0], mask))
else:
best_iou.append(torch.zeros(true_box.shape[1:4]).cuda())
best_iou = torch.stack(best_iou)
ignore_mask = (best_iou < self.ignore_thresh).float()
ignore_mask = ignore_mask.unsqueeze(-1)
return ignore_mask
def single_batch_nms(candidate_boxes):
y_mask = candidate_boxes[
..., 4] >= self.score_threshold # true or false
candidate_boxes = candidate_boxes[y_mask]
outputs = torch.zeros(
(self.max_detection + 1, candidate_boxes.size(-1)))
indices = []
updates = []
count = 0
# candidate_boxes가 없거나 max_detection을 다 채울때 까지 반복
while candidate_boxes.size(0) > 0 and count < self.max_detection:
# candidate_boxes 중에서 점수가 가장 높은 박스 pick
best_idx = torch.argmax(candidate_boxes[..., 4], dim=0)
best_box = candidate_boxes[best_idx]
indices.append([count] * candidate_boxes.size(-1))
updates.append(best_box)
count += 1
# best_box는 candidate_boxes에서 제거
candidate_boxes = torch.cat(
(candidate_boxes[0:best_idx],
candidate_boxes[best_idx + 1:candidate_boxes.size(0)]),
dim=0)
# best_box와 모든 candidate_boxes 비교
iou = broadcast_iou(best_box[0:4], candidate_boxes[..., 0:4])
# iou가 iou_threshold보다 큰 후보 상자 제거
candidate_boxes = candidate_boxes[iou <= self.iou_threshold]
# 한번이라도 count가 됬을 때
if count > 0:
count_idx = [[self.max_detection] * candidate_boxes.size(-1)]
count_update = [
torch.zeros(candidate_boxes.size(-1)).fill_(count)
]
indices = torch.cat(
(torch.tensor(indices), torch.tensor(count_idx)), dim=0)
updates = torch.cat(
(torch.stack(updates), torch.stack(count_update).cuda()),
dim=0)
# dim=0으로 outputs의 indices위치에 updates값 넣기
outputs = outputs.cuda().scatter_(0, indices.cuda(), updates)
return outputs
def calc_ignore_mask(self, true_obj, true_box, pred_box):
true_box_shape = tf.shape(true_box)
pred_box_shape = tf.shape(pred_box)
true_box = tf.reshape(true_box, [true_box_shape[0], -1, 4])
true_box = tf.sort(true_box, axis=1, direction="DESCENDING")
true_box = true_box[:, 0:100, :]
pred_box = tf.reshape(pred_box, [pred_box_shape[0], -1, 4])
iou = broadcast_iou(pred_box, true_box)
best_iou = tf.reduce_max(iou, axis=-1)
best_iou = tf.reshape(best_iou, [
pred_box_shape[0], pred_box_shape[1], pred_box_shape[2],
pred_box_shape[3]
])
ignore_mask = tf.cast(best_iou < self.ignore_thresh, tf.float32)
ignore_mask = tf.expand_dims(ignore_mask, axis=-1)
return ignore_mask
def single_batch_nms(candidate_boxes):
# filter out predictions with score less than score_threshold
candidate_boxes = tf.boolean_mask(
candidate_boxes, candidate_boxes[..., 4] >= score_threshold)
outputs = tf.zeros((max_detection + 1,
tf.shape(candidate_boxes)[-1]))
indices = []
updates = []
count = 0
# keep running this until there's no more candidate box or max_detection is met
while tf.shape(candidate_boxes)[0] > 0 and count < max_detection:
# pick the box with the highest score
best_idx = tf.math.argmax(candidate_boxes[..., 4], axis=0)
best_box = candidate_boxes[best_idx]
# add this best box to the output
indices.append([count])
updates.append(best_box)
count += 1
# remove this box from candidate boxes
candidate_boxes = tf.concat([
candidate_boxes[0:best_idx],
candidate_boxes[best_idx + 1:tf.shape(candidate_boxes)[0]]
],
axis=0)
# calculate IOU between this box and all remaining candidate boxes
iou = broadcast_iou(best_box[0:4], candidate_boxes[..., 0:4])
# remove all candidate boxes with IOU bigger than iou_threshold
candidate_boxes = tf.boolean_mask(candidate_boxes,
iou[0] <= iou_threshold)
if count > 0:
# also append num_detection to the result
count_index = [[max_detection]]
count_updates = [
tf.fill([tf.shape(candidate_boxes)[-1]], count)
]
indices = tf.concat([indices, count_index], axis=0)
updates = tf.concat([updates, count_updates], axis=0)
outputs = tf.tensor_scatter_nd_update(outputs, indices,
updates)
return outputs
def calc_ignore_mask(self, true_obj, true_box, pred_box):
# eg. true_obj (1, 13, 13, 3, 1)
true_obj = tf.squeeze(true_obj, axis=-1)
# eg. true_obj (1, 13, 13, 3)
# eg. true_box (1, 13, 13, 3, 4)
# eg. pred_box (1, 13, 13, 2, 4)
# eg. true_box_filtered (2, 4) it was (3, 4) but one element got filtered out
true_box_filtered = tf.boolean_mask(true_box,
tf.cast(true_obj, tf.bool))
# YOLOv3:
# "If the bounding box prior is not the best but does overlap a ground
# truth object by more than some threshold we ignore the prediction,
# following [17]. We use the threshold of .5."
# calculate the iou for each pair of pred bbox and true bbox, then find the best among them
# eg. best_iou (1, 1, 1, 2)
best_iou = tf.reduce_max(broadcast_iou(pred_box, true_box_filtered),
axis=-1)
# if best iou is higher than threshold, set the box to be ignored for noobj loss
# eg. ignore_mask(1, 1, 1, 2)
ignore_mask = tf.cast(best_iou < self.ignore_thresh, tf.float32)
ignore_mask = tf.expand_dims(ignore_mask, axis=-1)
return ignore_mask
