PaddleOCR/ppocr/modeling/stns/tps.py

262 lines
10 KiB
Python
Executable File

#copyright (c) 2019 PaddlePaddle Authors. All Rights Reserve.
#
#Licensed under the Apache License, Version 2.0 (the "License");
#you may not use this file except in compliance with the License.
#You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
#Unless required by applicable law or agreed to in writing, software
#distributed under the License is distributed on an "AS IS" BASIS,
#WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#See the License for the specific language governing permissions and
#limitations under the License.
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
import math
import paddle.fluid as fluid
import paddle.fluid.layers as layers
from paddle.fluid.param_attr import ParamAttr
import numpy as np
class LocalizationNetwork(object):
def __init__(self, params):
super(LocalizationNetwork, self).__init__()
self.F = params['num_fiducial']
self.loc_lr = params['loc_lr']
self.model_name = params['model_name']
def conv_bn_layer(self,
input,
num_filters,
filter_size,
stride=1,
groups=1,
act=None,
name=None):
conv = layers.conv2d(
input=input,
num_filters=num_filters,
filter_size=filter_size,
stride=stride,
padding=(filter_size - 1) // 2,
groups=groups,
act=None,
param_attr=ParamAttr(name=name + "_weights"),
bias_attr=False)
bn_name = "bn_" + name
return layers.batch_norm(
input=conv,
act=act,
param_attr=ParamAttr(name=bn_name + '_scale'),
bias_attr=ParamAttr(bn_name + '_offset'),
moving_mean_name=bn_name + '_mean',
moving_variance_name=bn_name + '_variance')
def get_initial_fiducials(self):
""" see RARE paper Fig. 6 (a) """
F = self.F
ctrl_pts_x = np.linspace(-1.0, 1.0, int(F / 2))
ctrl_pts_y_top = np.linspace(0.0, -1.0, num=int(F / 2))
ctrl_pts_y_bottom = np.linspace(1.0, 0.0, num=int(F / 2))
ctrl_pts_top = np.stack([ctrl_pts_x, ctrl_pts_y_top], axis=1)
ctrl_pts_bottom = np.stack([ctrl_pts_x, ctrl_pts_y_bottom], axis=1)
initial_bias = np.concatenate([ctrl_pts_top, ctrl_pts_bottom], axis=0)
return initial_bias
def __call__(self, image):
F = self.F
loc_lr = self.loc_lr
if self.model_name == "large":
num_filters_list = [64, 128, 256, 512]
fc_dim = 256
else:
num_filters_list = [16, 32, 64, 128]
fc_dim = 64
for fno in range(len(num_filters_list)):
num_filters = num_filters_list[fno]
name = "loc_conv%d" % fno
if fno == 0:
conv = self.conv_bn_layer(
image, num_filters, 3, act='relu', name=name)
else:
conv = self.conv_bn_layer(
pool, num_filters, 3, act='relu', name=name)
if fno == len(num_filters_list) - 1:
pool = layers.adaptive_pool2d(
input=conv, pool_size=[1, 1], pool_type='avg')
else:
pool = layers.pool2d(
input=conv,
pool_size=2,
pool_stride=2,
pool_padding=0,
pool_type='max')
name = "loc_fc1"
stdv = 1.0 / math.sqrt(pool.shape[1] * 1.0)
fc1 = layers.fc(input=pool,
size=fc_dim,
param_attr=fluid.param_attr.ParamAttr(
learning_rate=loc_lr,
initializer=fluid.initializer.Uniform(-stdv, stdv),
name=name + "_w"),
act='relu',
name=name)
initial_bias = self.get_initial_fiducials()
initial_bias = initial_bias.reshape(-1)
name = "loc_fc2"
param_attr = fluid.param_attr.ParamAttr(
learning_rate=loc_lr,
initializer=fluid.initializer.NumpyArrayInitializer(
np.zeros([fc_dim, F * 2])),
name=name + "_w")
bias_attr = fluid.param_attr.ParamAttr(
learning_rate=loc_lr,
initializer=fluid.initializer.NumpyArrayInitializer(initial_bias),
name=name + "_b")
fc2 = layers.fc(input=fc1,
size=F * 2,
param_attr=param_attr,
bias_attr=bias_attr,
name=name)
batch_C_prime = layers.reshape(x=fc2, shape=[-1, F, 2], inplace=False)
return batch_C_prime
class GridGenerator(object):
def __init__(self, params):
super(GridGenerator, self).__init__()
self.eps = 1e-6
self.F = params['num_fiducial']
def build_C(self):
""" Return coordinates of fiducial points in I_r; C """
F = self.F
ctrl_pts_x = np.linspace(-1.0, 1.0, int(F / 2))
ctrl_pts_y_top = -1 * np.ones(int(F / 2))
ctrl_pts_y_bottom = np.ones(int(F / 2))
ctrl_pts_top = np.stack([ctrl_pts_x, ctrl_pts_y_top], axis=1)
ctrl_pts_bottom = np.stack([ctrl_pts_x, ctrl_pts_y_bottom], axis=1)
C = np.concatenate([ctrl_pts_top, ctrl_pts_bottom], axis=0)
return C # F x 2
def build_P(self, I_r_size):
I_r_width, I_r_height = I_r_size
I_r_grid_x = (np.arange(-I_r_width, I_r_width, 2) + 1.0)\
/ I_r_width # self.I_r_width
I_r_grid_y = (np.arange(-I_r_height, I_r_height, 2) + 1.0)\
/ I_r_height # self.I_r_height
# P: self.I_r_width x self.I_r_height x 2
P = np.stack(np.meshgrid(I_r_grid_x, I_r_grid_y), axis=2)
# n (= self.I_r_width x self.I_r_height) x 2
return P.reshape([-1, 2])
def build_inv_delta_C(self, C):
""" Return inv_delta_C which is needed to calculate T """
F = self.F
hat_C = np.zeros((F, F), dtype=float) # F x F
for i in range(0, F):
for j in range(i, F):
r = np.linalg.norm(C[i] - C[j])
hat_C[i, j] = r
hat_C[j, i] = r
np.fill_diagonal(hat_C, 1)
hat_C = (hat_C**2) * np.log(hat_C)
# print(C.shape, hat_C.shape)
delta_C = np.concatenate( # F+3 x F+3
[
np.concatenate(
[np.ones((F, 1)), C, hat_C], axis=1), # F x F+3
np.concatenate(
[np.zeros((2, 3)), np.transpose(C)], axis=1), # 2 x F+3
np.concatenate(
[np.zeros((1, 3)), np.ones((1, F))], axis=1) # 1 x F+3
],
axis=0)
inv_delta_C = np.linalg.inv(delta_C)
return inv_delta_C # F+3 x F+3
def build_P_hat(self, C, P):
F = self.F
eps = self.eps
n = P.shape[0] # n (= self.I_r_width x self.I_r_height)
#P_tile: n x 2 -> n x 1 x 2 -> n x F x 2
P_tile = np.tile(np.expand_dims(P, axis=1), (1, F, 1))
C_tile = np.expand_dims(C, axis=0) # 1 x F x 2
P_diff = P_tile - C_tile # n x F x 2
#rbf_norm: n x F
rbf_norm = np.linalg.norm(P_diff, ord=2, axis=2, keepdims=False)
#rbf: n x F
rbf = np.multiply(np.square(rbf_norm), np.log(rbf_norm + eps))
P_hat = np.concatenate([np.ones((n, 1)), P, rbf], axis=1)
return P_hat # n x F+3
def get_expand_tensor(self, batch_C_prime):
name = "ex_fc"
initializer = fluid.initializer.ConstantInitializer(value=0.0)
param_attr = fluid.param_attr.ParamAttr(
learning_rate=0.0, initializer=initializer, name=name + "_w")
bias_attr = fluid.param_attr.ParamAttr(
learning_rate=0.0, initializer=initializer, name=name + "_b")
batch_C_ex_part_tensor = fluid.layers.fc(input=batch_C_prime,
size=6,
param_attr=param_attr,
bias_attr=bias_attr,
name=name)
batch_C_ex_part_tensor = fluid.layers.reshape(
x=batch_C_ex_part_tensor, shape=[-1, 3, 2])
return batch_C_ex_part_tensor
def __call__(self, batch_C_prime, I_r_size):
C = self.build_C()
P = self.build_P(I_r_size)
inv_delta_C = self.build_inv_delta_C(C).astype('float32')
P_hat = self.build_P_hat(C, P).astype('float32')
inv_delta_C_tensor = layers.create_tensor(dtype='float32')
layers.assign(inv_delta_C, inv_delta_C_tensor)
inv_delta_C_tensor.stop_gradient = True
P_hat_tensor = layers.create_tensor(dtype='float32')
layers.assign(P_hat, P_hat_tensor)
P_hat_tensor.stop_gradient = True
batch_C_ex_part_tensor = self.get_expand_tensor(batch_C_prime)
# batch_C_ex_part_tensor = create_tmp_var(
# fluid.default_main_program(),
# name='batch_C_ex_part_tensor',
# dtype='float32', shape=[-1, 3, 2])
# layers.py_func(func=get_batch_C_expand,
# x=[batch_C_prime], out=[batch_C_ex_part_tensor])
batch_C_ex_part_tensor.stop_gradient = True
batch_C_prime_with_zeros = layers.concat(
[batch_C_prime, batch_C_ex_part_tensor], axis=1)
batch_T = layers.matmul(inv_delta_C_tensor, batch_C_prime_with_zeros)
batch_P_prime = layers.matmul(P_hat_tensor, batch_T)
return batch_P_prime
class TPS(object):
def __init__(self, params):
super(TPS, self).__init__()
self.loc_net = LocalizationNetwork(params)
self.grid_generator = GridGenerator(params)
def __call__(self, image):
batch_C_prime = self.loc_net(image)
I_r_size = [image.shape[3], image.shape[2]]
batch_P_prime = self.grid_generator(batch_C_prime, I_r_size)
batch_P_prime = layers.reshape(
x=batch_P_prime, shape=[-1, image.shape[2], image.shape[3], 2])
batch_I_r = layers.grid_sampler(x=image, grid=batch_P_prime)
image.stop_gradient = False
return batch_I_r