164 lines
6.2 KiB
Python
164 lines
6.2 KiB
Python
# copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import numpy as np
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class WarpMLS:
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def __init__(self, src, src_pts, dst_pts, dst_w, dst_h, trans_ratio=1.):
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self.src = src
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self.src_pts = src_pts
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self.dst_pts = dst_pts
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self.pt_count = len(self.dst_pts)
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self.dst_w = dst_w
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self.dst_h = dst_h
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self.trans_ratio = trans_ratio
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self.grid_size = 100
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self.rdx = np.zeros((self.dst_h, self.dst_w))
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self.rdy = np.zeros((self.dst_h, self.dst_w))
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@staticmethod
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def __bilinear_interp(x, y, v11, v12, v21, v22):
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return (v11 * (1 - y) + v12 * y) * (1 - x) + (v21 *
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(1 - y) + v22 * y) * x
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def generate(self):
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self.calc_delta()
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return self.gen_img()
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def calc_delta(self):
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w = np.zeros(self.pt_count, dtype=np.float32)
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if self.pt_count < 2:
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return
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i = 0
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while 1:
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if self.dst_w <= i < self.dst_w + self.grid_size - 1:
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i = self.dst_w - 1
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elif i >= self.dst_w:
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break
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j = 0
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while 1:
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if self.dst_h <= j < self.dst_h + self.grid_size - 1:
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j = self.dst_h - 1
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elif j >= self.dst_h:
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break
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sw = 0
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swp = np.zeros(2, dtype=np.float32)
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swq = np.zeros(2, dtype=np.float32)
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new_pt = np.zeros(2, dtype=np.float32)
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cur_pt = np.array([i, j], dtype=np.float32)
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k = 0
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for k in range(self.pt_count):
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if i == self.dst_pts[k][0] and j == self.dst_pts[k][1]:
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break
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w[k] = 1. / (
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(i - self.dst_pts[k][0]) * (i - self.dst_pts[k][0]) +
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(j - self.dst_pts[k][1]) * (j - self.dst_pts[k][1]))
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sw += w[k]
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swp = swp + w[k] * np.array(self.dst_pts[k])
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swq = swq + w[k] * np.array(self.src_pts[k])
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if k == self.pt_count - 1:
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pstar = 1 / sw * swp
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qstar = 1 / sw * swq
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miu_s = 0
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for k in range(self.pt_count):
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if i == self.dst_pts[k][0] and j == self.dst_pts[k][1]:
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continue
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pt_i = self.dst_pts[k] - pstar
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miu_s += w[k] * np.sum(pt_i * pt_i)
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cur_pt -= pstar
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cur_pt_j = np.array([-cur_pt[1], cur_pt[0]])
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for k in range(self.pt_count):
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if i == self.dst_pts[k][0] and j == self.dst_pts[k][1]:
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continue
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pt_i = self.dst_pts[k] - pstar
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pt_j = np.array([-pt_i[1], pt_i[0]])
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tmp_pt = np.zeros(2, dtype=np.float32)
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tmp_pt[0] = np.sum(pt_i * cur_pt) * self.src_pts[k][0] - \
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np.sum(pt_j * cur_pt) * self.src_pts[k][1]
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tmp_pt[1] = -np.sum(pt_i * cur_pt_j) * self.src_pts[k][0] + \
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np.sum(pt_j * cur_pt_j) * self.src_pts[k][1]
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tmp_pt *= (w[k] / miu_s)
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new_pt += tmp_pt
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new_pt += qstar
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else:
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new_pt = self.src_pts[k]
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self.rdx[j, i] = new_pt[0] - i
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self.rdy[j, i] = new_pt[1] - j
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j += self.grid_size
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i += self.grid_size
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def gen_img(self):
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src_h, src_w = self.src.shape[:2]
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dst = np.zeros_like(self.src, dtype=np.float32)
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for i in np.arange(0, self.dst_h, self.grid_size):
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for j in np.arange(0, self.dst_w, self.grid_size):
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ni = i + self.grid_size
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nj = j + self.grid_size
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w = h = self.grid_size
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if ni >= self.dst_h:
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ni = self.dst_h - 1
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h = ni - i + 1
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if nj >= self.dst_w:
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nj = self.dst_w - 1
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w = nj - j + 1
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di = np.reshape(np.arange(h), (-1, 1))
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dj = np.reshape(np.arange(w), (1, -1))
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delta_x = self.__bilinear_interp(
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di / h, dj / w, self.rdx[i, j], self.rdx[i, nj],
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self.rdx[ni, j], self.rdx[ni, nj])
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delta_y = self.__bilinear_interp(
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di / h, dj / w, self.rdy[i, j], self.rdy[i, nj],
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self.rdy[ni, j], self.rdy[ni, nj])
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nx = j + dj + delta_x * self.trans_ratio
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ny = i + di + delta_y * self.trans_ratio
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nx = np.clip(nx, 0, src_w - 1)
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ny = np.clip(ny, 0, src_h - 1)
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nxi = np.array(np.floor(nx), dtype=np.int32)
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nyi = np.array(np.floor(ny), dtype=np.int32)
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nxi1 = np.array(np.ceil(nx), dtype=np.int32)
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nyi1 = np.array(np.ceil(ny), dtype=np.int32)
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if len(self.src.shape) == 3:
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x = np.tile(np.expand_dims(ny - nyi, axis=-1), (1, 1, 3))
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y = np.tile(np.expand_dims(nx - nxi, axis=-1), (1, 1, 3))
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else:
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x = ny - nyi
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y = nx - nxi
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dst[i:i + h, j:j + w] = self.__bilinear_interp(
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x, y, self.src[nyi, nxi], self.src[nyi, nxi1],
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self.src[nyi1, nxi], self.src[nyi1, nxi1])
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dst = np.clip(dst, 0, 255)
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dst = np.array(dst, dtype=np.uint8)
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return dst |