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# https://github.com/IDEA-Research/DWPose
from typing import List, Tuple
import cv2
import numpy as np
import onnxruntime as ort
def preprocess(
img: np.ndarray, out_bbox, input_size: Tuple[int, int] = (192, 256)
) -> Tuple[np.ndarray, np.ndarray, np.ndarray]:
"""Do preprocessing for RTMPose model inference.
Args:
img (np.ndarray): Input image in shape.
input_size (tuple): Input image size in shape (w, h).
Returns:
tuple:
- resized_img (np.ndarray): Preprocessed image.
- center (np.ndarray): Center of image.
- scale (np.ndarray): Scale of image.
"""
# get shape of image
img_shape = img.shape[:2]
out_img, out_center, out_scale = [], [], []
if len(out_bbox) == 0:
out_bbox = [[0, 0, img_shape[1], img_shape[0]]]
for i in range(len(out_bbox)):
x0 = out_bbox[i][0]
y0 = out_bbox[i][1]
x1 = out_bbox[i][2]
y1 = out_bbox[i][3]
bbox = np.array([x0, y0, x1, y1])
# get center and scale
center, scale = bbox_xyxy2cs(bbox, padding=1.25)
# do affine transformation
resized_img, scale = top_down_affine(input_size, scale, center, img)
# normalize image
mean = np.array([123.675, 116.28, 103.53])
std = np.array([58.395, 57.12, 57.375])
resized_img = (resized_img - mean) / std
out_img.append(resized_img)
out_center.append(center)
out_scale.append(scale)
return out_img, out_center, out_scale
def inference(sess: ort.InferenceSession, img: np.ndarray) -> np.ndarray:
"""Inference RTMPose model.
Args:
sess (ort.InferenceSession): ONNXRuntime session.
img (np.ndarray): Input image in shape.
Returns:
outputs (np.ndarray): Output of RTMPose model.
"""
all_out = []
# build input
for i in range(len(img)):
input = [img[i].transpose(2, 0, 1)]
# build output
sess_input = {sess.get_inputs()[0].name: input}
sess_output = []
for out in sess.get_outputs():
sess_output.append(out.name)
# run model
outputs = sess.run(sess_output, sess_input)
all_out.append(outputs)
return all_out
def postprocess(
outputs: List[np.ndarray],
model_input_size: Tuple[int, int],
center: Tuple[int, int],
scale: Tuple[int, int],
simcc_split_ratio: float = 2.0,
) -> Tuple[np.ndarray, np.ndarray]:
"""Postprocess for RTMPose model output.
Args:
outputs (np.ndarray): Output of RTMPose model.
model_input_size (tuple): RTMPose model Input image size.
center (tuple): Center of bbox in shape (x, y).
scale (tuple): Scale of bbox in shape (w, h).
simcc_split_ratio (float): Split ratio of simcc.
Returns:
tuple:
- keypoints (np.ndarray): Rescaled keypoints.
- scores (np.ndarray): Model predict scores.
"""
all_key = []
all_score = []
for i in range(len(outputs)):
# use simcc to decode
simcc_x, simcc_y = outputs[i]
keypoints, scores = decode(simcc_x, simcc_y, simcc_split_ratio)
# rescale keypoints
keypoints = keypoints / model_input_size * scale[i] + center[i] - scale[i] / 2
all_key.append(keypoints[0])
all_score.append(scores[0])
return np.array(all_key), np.array(all_score)
def bbox_xyxy2cs(
bbox: np.ndarray, padding: float = 1.0
) -> Tuple[np.ndarray, np.ndarray]:
"""Transform the bbox format from (x,y,w,h) into (center, scale)
Args:
bbox (ndarray): Bounding box(es) in shape (4,) or (n, 4), formatted
as (left, top, right, bottom)
padding (float): BBox padding factor that will be multilied to scale.
Default: 1.0
Returns:
tuple: A tuple containing center and scale.
- np.ndarray[float32]: Center (x, y) of the bbox in shape (2,) or
(n, 2)
- np.ndarray[float32]: Scale (w, h) of the bbox in shape (2,) or
(n, 2)
"""
# convert single bbox from (4, ) to (1, 4)
dim = bbox.ndim
if dim == 1:
bbox = bbox[None, :]
# get bbox center and scale
x1, y1, x2, y2 = np.hsplit(bbox, [1, 2, 3])
center = np.hstack([x1 + x2, y1 + y2]) * 0.5
scale = np.hstack([x2 - x1, y2 - y1]) * padding
if dim == 1:
center = center[0]
scale = scale[0]
return center, scale
def _fix_aspect_ratio(bbox_scale: np.ndarray, aspect_ratio: float) -> np.ndarray:
"""Extend the scale to match the given aspect ratio.
Args:
scale (np.ndarray): The image scale (w, h) in shape (2, )
aspect_ratio (float): The ratio of ``w/h``
Returns:
np.ndarray: The reshaped image scale in (2, )
"""
w, h = np.hsplit(bbox_scale, [1])
bbox_scale = np.where(
w > h * aspect_ratio,
np.hstack([w, w / aspect_ratio]),
np.hstack([h * aspect_ratio, h]),
)
return bbox_scale
def _rotate_point(pt: np.ndarray, angle_rad: float) -> np.ndarray:
"""Rotate a point by an angle.
Args:
pt (np.ndarray): 2D point coordinates (x, y) in shape (2, )
angle_rad (float): rotation angle in radian
Returns:
np.ndarray: Rotated point in shape (2, )
"""
sn, cs = np.sin(angle_rad), np.cos(angle_rad)
rot_mat = np.array([[cs, -sn], [sn, cs]])
return rot_mat @ pt
def _get_3rd_point(a: np.ndarray, b: np.ndarray) -> np.ndarray:
"""To calculate the affine matrix, three pairs of points are required. This
function is used to get the 3rd point, given 2D points a & b.
The 3rd point is defined by rotating vector `a - b` by 90 degrees
anticlockwise, using b as the rotation center.
Args:
a (np.ndarray): The 1st point (x,y) in shape (2, )
b (np.ndarray): The 2nd point (x,y) in shape (2, )
Returns:
np.ndarray: The 3rd point.
"""
direction = a - b
c = b + np.r_[-direction[1], direction[0]]
return c
def get_warp_matrix(
center: np.ndarray,
scale: np.ndarray,
rot: float,
output_size: Tuple[int, int],
shift: Tuple[float, float] = (0.0, 0.0),
inv: bool = False,
) -> np.ndarray:
"""Calculate the affine transformation matrix that can warp the bbox area
in the input image to the output size.
Args:
center (np.ndarray[2, ]): Center of the bounding box (x, y).
scale (np.ndarray[2, ]): Scale of the bounding box
wrt [width, height].
rot (float): Rotation angle (degree).
output_size (np.ndarray[2, ] | list(2,)): Size of the
destination heatmaps.
shift (0-100%): Shift translation ratio wrt the width/height.
Default (0., 0.).
inv (bool): Option to inverse the affine transform direction.
(inv=False: src->dst or inv=True: dst->src)
Returns:
np.ndarray: A 2x3 transformation matrix
"""
shift = np.array(shift)
src_w = scale[0]
dst_w = output_size[0]
dst_h = output_size[1]
# compute transformation matrix
rot_rad = np.deg2rad(rot)
src_dir = _rotate_point(np.array([0.0, src_w * -0.5]), rot_rad)
dst_dir = np.array([0.0, dst_w * -0.5])
# get four corners of the src rectangle in the original image
src = np.zeros((3, 2), dtype=np.float32)
src[0, :] = center + scale * shift
src[1, :] = center + src_dir + scale * shift
src[2, :] = _get_3rd_point(src[0, :], src[1, :])
# get four corners of the dst rectangle in the input image
dst = np.zeros((3, 2), dtype=np.float32)
dst[0, :] = [dst_w * 0.5, dst_h * 0.5]
dst[1, :] = np.array([dst_w * 0.5, dst_h * 0.5]) + dst_dir
dst[2, :] = _get_3rd_point(dst[0, :], dst[1, :])
if inv:
warp_mat = cv2.getAffineTransform(np.float32(dst), np.float32(src))
else:
warp_mat = cv2.getAffineTransform(np.float32(src), np.float32(dst))
return warp_mat
def top_down_affine(
input_size: dict, bbox_scale: dict, bbox_center: dict, img: np.ndarray
) -> Tuple[np.ndarray, np.ndarray]:
"""Get the bbox image as the model input by affine transform.
Args:
input_size (dict): The input size of the model.
bbox_scale (dict): The bbox scale of the img.
bbox_center (dict): The bbox center of the img.
img (np.ndarray): The original image.
Returns:
tuple: A tuple containing center and scale.
- np.ndarray[float32]: img after affine transform.
- np.ndarray[float32]: bbox scale after affine transform.
"""
w, h = input_size
warp_size = (int(w), int(h))
# reshape bbox to fixed aspect ratio
bbox_scale = _fix_aspect_ratio(bbox_scale, aspect_ratio=w / h)
# get the affine matrix
center = bbox_center
scale = bbox_scale
rot = 0
warp_mat = get_warp_matrix(center, scale, rot, output_size=(w, h))
# do affine transform
img = cv2.warpAffine(img, warp_mat, warp_size, flags=cv2.INTER_LINEAR)
return img, bbox_scale
def get_simcc_maximum(
simcc_x: np.ndarray, simcc_y: np.ndarray
) -> Tuple[np.ndarray, np.ndarray]:
"""Get maximum response location and value from simcc representations.
Note:
instance number: N
num_keypoints: K
heatmap height: H
heatmap width: W
Args:
simcc_x (np.ndarray): x-axis SimCC in shape (K, Wx) or (N, K, Wx)
simcc_y (np.ndarray): y-axis SimCC in shape (K, Wy) or (N, K, Wy)
Returns:
tuple:
- locs (np.ndarray): locations of maximum heatmap responses in shape
(K, 2) or (N, K, 2)
- vals (np.ndarray): values of maximum heatmap responses in shape
(K,) or (N, K)
"""
N, K, Wx = simcc_x.shape
simcc_x = simcc_x.reshape(N * K, -1)
simcc_y = simcc_y.reshape(N * K, -1)
# get maximum value locations
x_locs = np.argmax(simcc_x, axis=1)
y_locs = np.argmax(simcc_y, axis=1)
locs = np.stack((x_locs, y_locs), axis=-1).astype(np.float32)
max_val_x = np.amax(simcc_x, axis=1)
max_val_y = np.amax(simcc_y, axis=1)
# get maximum value across x and y axis
mask = max_val_x > max_val_y
max_val_x[mask] = max_val_y[mask]
vals = max_val_x
locs[vals <= 0.0] = -1
# reshape
locs = locs.reshape(N, K, 2)
vals = vals.reshape(N, K)
return locs, vals
def decode(
simcc_x: np.ndarray, simcc_y: np.ndarray, simcc_split_ratio
) -> Tuple[np.ndarray, np.ndarray]:
"""Modulate simcc distribution with Gaussian.
Args:
simcc_x (np.ndarray[K, Wx]): model predicted simcc in x.
simcc_y (np.ndarray[K, Wy]): model predicted simcc in y.
simcc_split_ratio (int): The split ratio of simcc.
Returns:
tuple: A tuple containing center and scale.
- np.ndarray[float32]: keypoints in shape (K, 2) or (n, K, 2)
- np.ndarray[float32]: scores in shape (K,) or (n, K)
"""
keypoints, scores = get_simcc_maximum(simcc_x, simcc_y)
keypoints /= simcc_split_ratio
return keypoints, scores
def inference_pose(session, out_bbox, oriImg):
h, w = session.get_inputs()[0].shape[2:]
model_input_size = (w, h)
resized_img, center, scale = preprocess(oriImg, out_bbox, model_input_size)
outputs = inference(session, resized_img)
keypoints, scores = postprocess(outputs, model_input_size, center, scale)
return keypoints, scores