def adjust_input(in_data):#调整输入
"""
adjust the input from (h, w, c) to ( 1, c, h, w) for network input
Parameters:
----------
in_data: numpy array of shape (h, w, c)
input data
Returns:
-------
out_data: numpy array of shape (1, c, h, w)
reshaped array
"""
if in_data.dtype is not np.dtype('float32'):
out_data = in_data.astype(np.float32)
else:
out_data = in_data
out_data = out_data.transpose((2,0,1))
out_data = np.expand_dims(out_data, 0)
out_data = (out_data - 127.5)*0.0078125
return out_data
def generate_bbox(map, reg, scale, threshold):#生成bbox
"""
generate bbox from feature map
Parameters:
----------
map: numpy array , n x m x 1
detect score for each position
reg: numpy array , n x m x 4
bbox
scale: float number
scale of this detection
threshold: float number
detect threshold
Returns:
-------
bbox array
"""
stride = 2
cellsize = 12
t_index = np.where(map>threshold)
# find nothing
if t_index[0].size == 0:
return np.array([])
dx1, dy1, dx2, dy2 = [reg[0, i, t_index[0], t_index[1]] for i in range(4)]
reg = np.array([dx1, dy1, dx2, dy2])
score = map[t_index[0], t_index[1]]
boundingbox = np.vstack([np.round((stride*t_index[1]+1)/scale),
np.round((stride*t_index[0]+1)/scale),
np.round((stride*t_index[1]+1+cellsize)/scale),
np.round((stride*t_index[0]+1+cellsize)/scale),
score,
reg])
return boundingbox.T
def detect_first_stage(img, net, scale, threshold):#检测第一阶段
"""
run PNet for first stage
Parameters:
----------
img: numpy array, bgr order
input image
scale: float number
how much should the input image scale
net: PNet
worker
Returns:
-------
total_boxes : bboxes
"""
height, width, _ = img.shape
hs = int(math.ceil(height * scale))
ws = int(math.ceil(width * scale))
im_data = cv2.resize(img, (ws,hs))
# adjust for the network input
input_buf = adjust_input(im_data)
output = net.predict(input_buf)
boxes = generate_bbox(output[1][0,1,:,:], output[0], scale, threshold)
if boxes.size == 0:
return None
# nms
pick = nms(boxes[:,0:5], 0.5, mode='Union')
boxes = boxes[pick]
return boxes
def detect_first_stage_warpper( args ):
return detect_first_stage(*args)