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"""This script contains the image preprocessing code for Deep3DFaceRecon_pytorch | |
""" | |
import numpy as np | |
from scipy.io import loadmat | |
from PIL import Image | |
import cv2 | |
import os | |
from skimage import transform as trans | |
import torch | |
import warnings | |
warnings.filterwarnings("ignore", category=np.VisibleDeprecationWarning) | |
warnings.filterwarnings("ignore", category=FutureWarning) | |
# calculating least square problem for image alignment | |
def POS(xp, x): | |
npts = xp.shape[1] | |
A = np.zeros([2*npts, 8]) | |
A[0:2*npts-1:2, 0:3] = x.transpose() | |
A[0:2*npts-1:2, 3] = 1 | |
A[1:2*npts:2, 4:7] = x.transpose() | |
A[1:2*npts:2, 7] = 1 | |
b = np.reshape(xp.transpose(), [2*npts, 1]) | |
k, _, _, _ = np.linalg.lstsq(A, b) | |
R1 = k[0:3] | |
R2 = k[4:7] | |
sTx = k[3] | |
sTy = k[7] | |
s = (np.linalg.norm(R1) + np.linalg.norm(R2))/2 | |
t = np.stack([sTx, sTy], axis=0) | |
return t, s | |
# resize and crop images for face reconstruction | |
def resize_n_crop_img(img, lm, t, s, target_size=224., mask=None): | |
w0, h0 = img.size | |
w = (w0*s).astype(np.int32) | |
h = (h0*s).astype(np.int32) | |
left = (w/2 - target_size/2 + float((t[0] - w0/2)*s)).astype(np.int32) | |
right = left + target_size | |
up = (h/2 - target_size/2 + float((h0/2 - t[1])*s)).astype(np.int32) | |
below = up + target_size | |
img = img.resize((w, h), resample=Image.BICUBIC) | |
img = img.crop((left, up, right, below)) | |
if mask is not None: | |
mask = mask.resize((w, h), resample=Image.BICUBIC) | |
mask = mask.crop((left, up, right, below)) | |
lm = np.stack([lm[:, 0] - t[0] + w0/2, lm[:, 1] - | |
t[1] + h0/2], axis=1)*s | |
lm = lm - np.reshape( | |
np.array([(w/2 - target_size/2), (h/2-target_size/2)]), [1, 2]) | |
return img, lm, mask | |
# utils for face reconstruction | |
def extract_5p(lm): | |
lm_idx = np.array([31, 37, 40, 43, 46, 49, 55]) - 1 | |
lm5p = np.stack([lm[lm_idx[0], :], np.mean(lm[lm_idx[[1, 2]], :], 0), np.mean( | |
lm[lm_idx[[3, 4]], :], 0), lm[lm_idx[5], :], lm[lm_idx[6], :]], axis=0) | |
lm5p = lm5p[[1, 2, 0, 3, 4], :] | |
return lm5p | |
# utils for face reconstruction | |
def align_img(img, lm, lm3D, mask=None, target_size=224., rescale_factor=102.): | |
""" | |
Return: | |
transparams --numpy.array (raw_W, raw_H, scale, tx, ty) | |
img_new --PIL.Image (target_size, target_size, 3) | |
lm_new --numpy.array (68, 2), y direction is opposite to v direction | |
mask_new --PIL.Image (target_size, target_size) | |
Parameters: | |
img --PIL.Image (raw_H, raw_W, 3) | |
lm --numpy.array (68, 2), y direction is opposite to v direction | |
lm3D --numpy.array (5, 3) | |
mask --PIL.Image (raw_H, raw_W, 3) | |
""" | |
w0, h0 = img.size | |
if lm.shape[0] != 5: | |
lm5p = extract_5p(lm) | |
else: | |
lm5p = lm | |
# calculate translation and scale factors using 5 facial landmarks and standard landmarks of a 3D face | |
t, s = POS(lm5p.transpose(), lm3D.transpose()) | |
s = rescale_factor/s | |
# processing the image | |
img_new, lm_new, mask_new = resize_n_crop_img(img, lm, t, s, target_size=target_size, mask=mask) | |
trans_params = np.array([w0, h0, s, t[0], t[1]]) | |
return trans_params, img_new, lm_new, mask_new | |