def back_projection(y_sr, y_lr, down_kernel, up_kernel, sf=None):
"""Projects the error between the downscaled SR image and the LR image"""
y_sr += imresize(y_lr - imresize(y_sr,
scale_factor=1.0 / sf,
output_shape=y_lr.shape,
kernel=down_kernel),
scale_factor=sf,
output_shape=y_sr.shape,
kernel=up_kernel)
return np.clip(y_sr, 0, 1)
def process_for_lr():
r""" The low resolution data set is preliminarily processed.
"""
for filename in tqdm(lr_files, desc="Generating images from lr dir"):
img = Image.open(filename)
img = pil2tensor(img)
# Remove noise
img = utils.imresize(img, 1.0 / args.cleanup_factor, True)
_, w, h = img.size()
w = w - w % args.upscale_factor
h = h - h % args.upscale_factor
img = img[:, :w, :h]
# Save high resolution img
img = tensor2pil(img)
img.save(os.path.join(hr_dir, os.path.basename(filename)), "bmp")
# The noise distribution obtained in kernelGAN is used to adjust the image.
kernel_path = kernel_paths[np.random.randint(0, len(kernel_paths))]
mat = loadmat(kernel_path)
k = np.array([mat["Kernel"]]).squeeze()
img = imresize(np.array(img),
scale_factor=1.0 / args.upscale_factor,
kernel=k)
# Save low resolution img
img = tensor2pil(img)
img.save(os.path.join(lr_dir, os.path.basename(filename)), "bmp")
def create_prob_maps(self, scale_factor):
# Create loss maps for input image and downscaled one
loss_map_big = create_gradient_map(self.input_image)
loss_map_sml = create_gradient_map(imresize(im=self.input_image, scale_factor=scale_factor, kernel='cubic'))
# Create corresponding probability maps
prob_map_big = create_probability_map(loss_map_big, self.d_input_shape)
prob_map_sml = create_probability_map(nn_interpolation(loss_map_sml, int(1 / scale_factor)), self.g_input_shape)
return prob_map_big, prob_map_sml
def back_project_image(lr,
sf=2,
output_shape=None,
down_kernel='cubic',
up_kernel='cubic',
bp_iters=8):
"""Runs 'bp_iters' iteration of back projection SR technique"""
tmp_sr = imresize(lr,
scale_factor=sf,
output_shape=output_shape,
kernel=up_kernel)
for _ in range(bp_iters):
tmp_sr = back_projection(y_sr=tmp_sr,
y_lr=lr,
down_kernel=down_kernel,
up_kernel=up_kernel,
sf=sf)
return tmp_sr
_, w, h = resize2_img.size()
w = w - w % opt.upscale_factor
h = h - h % opt.upscale_factor
resize2_cut_img = resize2_img[:, :w, :h]
try:
file_name = os.path.basename(file)
file_id = file_name.split('.')[0]
kernel_path = os.path.join(
opt.kernel_path, file_id + '/' + file_id + '_kernel_x4.mat')
mat = loadmat(kernel_path)
path = os.path.join(tdsr_hr_dir, os.path.basename(file))
if not os.path.exists(path):
print(f'create_HrLr kernel_path:{kernel_path}')
HR_img = TF.to_pil_image(input_img)
HR_img.save(path, 'PNG')
k = np.array([mat['Kernel']]).squeeze()
resize_img = imresize(np.array(HR_img),
scale_factor=1.0 / opt.upscale_factor,
kernel=k)
path = os.path.join(tdsr_lr_dir, os.path.basename(file))
TF.to_pil_image(resize_img).save(path, 'PNG')
else:
print(f'skip kernel_path:{kernel_path}')
except Exception as e:
print(e)