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from __future__ import absolute_import, division, print_function, unicode_literals
import scipy.ndimage
from scipy.sparse.linalg import spsolve
from scipy import sparse
import scipy.io as sio
import numpy as np
from PIL import Image
import copy
import cv2
import os
import argparse
def sub2ind(pi, pj, imgH, imgW):
return pj + pi * imgW
def Poisson_blend(imgTrg, imgSrc_gx, imgSrc_gy, holeMask, edge=None):
imgH, imgW, nCh = imgTrg.shape
if not isinstance(edge, np.ndarray):
edge = np.zeros((imgH, imgW), dtype=np.float32)
# Initialize the reconstructed image
imgRecon = np.zeros((imgH, imgW, nCh), dtype=np.float32)
# prepare discrete Poisson equation
A, b = solvePoisson(holeMask, imgSrc_gx, imgSrc_gy, imgTrg, edge)
# Independently process each channel
for ch in range(nCh):
# solve Poisson equation
x = scipy.sparse.linalg.lsqr(A, b[:, ch, None])[0]
imgRecon[:, :, ch] = x.reshape(imgH, imgW)
# Combined with the known region in the target
holeMaskC = np.tile(np.expand_dims(holeMask, axis=2), (1, 1, nCh))
imgBlend = holeMaskC * imgRecon + (1 - holeMaskC) * imgTrg
# Fill in edge pixel
pi = np.expand_dims(np.where((holeMask * edge) == 1)[0], axis=1) # y, i
pj = np.expand_dims(np.where((holeMask * edge) == 1)[1], axis=1) # x, j
for k in range(len(pi)):
if pi[k, 0] - 1 >= 0:
if edge[pi[k, 0] - 1, pj[k, 0]] == 0:
imgBlend[pi[k, 0], pj[k, 0], :] = imgBlend[pi[k, 0] - 1, pj[k, 0], :]
continue
if pi[k, 0] + 1 <= imgH - 1:
if edge[pi[k, 0] + 1, pj[k, 0]] == 0:
imgBlend[pi[k, 0], pj[k, 0], :] = imgBlend[pi[k, 0] + 1, pj[k, 0], :]
continue
if pj[k, 0] - 1 >= 0:
if edge[pi[k, 0], pj[k, 0] - 1] == 0:
imgBlend[pi[k, 0], pj[k, 0], :] = imgBlend[pi[k, 0], pj[k, 0] - 1, :]
continue
if pj[k, 0] + 1 <= imgW - 1:
if edge[pi[k, 0], pj[k, 0] + 1] == 0:
imgBlend[pi[k, 0], pj[k, 0], :] = imgBlend[pi[k, 0], pj[k, 0] + 1, :]
return imgBlend
def solvePoisson(holeMask, imgSrc_gx, imgSrc_gy, imgTrg, edge):
# Prepare the linear system of equations for Poisson blending
imgH, imgW = holeMask.shape
N = imgH * imgW
# Number of unknown variables
numUnknownPix = holeMask.sum()
# 4-neighbors: dx and dy
dx = [1, 0, -1, 0]
dy = [0, 1, 0, -1]
# 3
# |
# 2 -- * -- 0
# |
# 1
#
# Initialize (I, J, S), for sparse matrix A where A(I(k), J(k)) = S(k)
I = np.empty((0, 1), dtype=np.float32)
J = np.empty((0, 1), dtype=np.float32)
S = np.empty((0, 1), dtype=np.float32)
# Initialize b
b = np.empty((0, 2), dtype=np.float32)
# Precompute unkonwn pixel position
pi = np.expand_dims(np.where(holeMask == 1)[0], axis=1) # y, i
pj = np.expand_dims(np.where(holeMask == 1)[1], axis=1) # x, j
pind = sub2ind(pi, pj, imgH, imgW)
# |--------------------|
# | y (i) |
# | x (j) * |
# | |
# |--------------------|
qi = np.concatenate((pi + dy[0],
pi + dy[1],
pi + dy[2],
pi + dy[3]), axis=1)
qj = np.concatenate((pj + dx[0],
pj + dx[1],
pj + dx[2],
pj + dx[3]), axis=1)
# Handling cases at image borders
validN = (qi >= 0) & (qi <= imgH - 1) & (qj >= 0) & (qj <= imgW - 1)
qind = np.zeros((validN.shape), dtype=np.float32)
qind[validN] = sub2ind(qi[validN], qj[validN], imgH, imgW)
e_start = 0 # equation counter start
e_stop = 0 # equation stop
# 4 neighbors
I, J, S, b, e_start, e_stop = constructEquation(0, validN, holeMask, edge, imgSrc_gx, imgSrc_gy, imgTrg, pi, pj, pind, qi, qj, qind, I, J, S, b, e_start, e_stop)
I, J, S, b, e_start, e_stop = constructEquation(1, validN, holeMask, edge, imgSrc_gx, imgSrc_gy, imgTrg, pi, pj, pind, qi, qj, qind, I, J, S, b, e_start, e_stop)
I, J, S, b, e_start, e_stop = constructEquation(2, validN, holeMask, edge, imgSrc_gx, imgSrc_gy, imgTrg, pi, pj, pind, qi, qj, qind, I, J, S, b, e_start, e_stop)
I, J, S, b, e_start, e_stop = constructEquation(3, validN, holeMask, edge, imgSrc_gx, imgSrc_gy, imgTrg, pi, pj, pind, qi, qj, qind, I, J, S, b, e_start, e_stop)
nEqn = len(b)
# Construct the sparse matrix A
A = sparse.csr_matrix((S[:, 0], (I[:, 0], J[:, 0])), shape=(nEqn, N))
return A, b
def constructEquation(n, validN, holeMask, edge, imgSrc_gx, imgSrc_gy, imgTrg, pi, pj, pind, qi, qj, qind, I, J, S, b, e_start, e_stop):
# Pixel that has valid neighbors
validNeighbor = validN[:, n]
# Change the out-of-boundary value to 0, in order to run edge[y,x]
# in the next line. It won't affect anything as validNeighbor is saved already
qi_tmp = copy.deepcopy(qi)
qj_tmp = copy.deepcopy(qj)
qi_tmp[np.invert(validNeighbor), n] = 0
qj_tmp[np.invert(validNeighbor), n] = 0
# Not edge
NotEdge = (edge[pi[:, 0], pj[:, 0]] == 0) * (edge[qi_tmp[:, n], qj_tmp[:, n]] == 0)
# Boundary constraint
Boundary = holeMask[qi_tmp[:, n], qj_tmp[:, n]] == 0
valid = validNeighbor * NotEdge * Boundary
J_tmp = pind[valid, :]
# num of equations: len(J_tmp)
e_stop = e_start + len(J_tmp)
I_tmp = np.arange(e_start, e_stop, dtype=np.float32).reshape(-1, 1)
e_start = e_stop
S_tmp = np.ones(J_tmp.shape, dtype=np.float32)
if n == 0:
b_tmp = - imgSrc_gx[pi[valid, 0], pj[valid, 0], :] + imgTrg[qi[valid, n], qj[valid, n], :]
elif n == 2:
b_tmp = imgSrc_gx[pi[valid, 0], pj[valid, 0] - 1, :] + imgTrg[qi[valid, n], qj[valid, n], :]
elif n == 1:
b_tmp = - imgSrc_gy[pi[valid, 0], pj[valid, 0], :] + imgTrg[qi[valid, n], qj[valid, n], :]
elif n == 3:
b_tmp = imgSrc_gy[pi[valid, 0] - 1, pj[valid, 0], :] + imgTrg[qi[valid, n], qj[valid, n], :]
I = np.concatenate((I, I_tmp))
J = np.concatenate((J, J_tmp))
S = np.concatenate((S, S_tmp))
b = np.concatenate((b, b_tmp))
# Non-boundary constraint
NonBoundary = holeMask[qi_tmp[:, n], qj_tmp[:, n]] == 1
valid = validNeighbor * NotEdge * NonBoundary
J_tmp = pind[valid, :]
# num of equations: len(J_tmp)
e_stop = e_start + len(J_tmp)
I_tmp = np.arange(e_start, e_stop, dtype=np.float32).reshape(-1, 1)
e_start = e_stop
S_tmp = np.ones(J_tmp.shape, dtype=np.float32)
if n == 0:
b_tmp = - imgSrc_gx[pi[valid, 0], pj[valid, 0], :]
elif n == 2:
b_tmp = imgSrc_gx[pi[valid, 0], pj[valid, 0] - 1, :]
elif n == 1:
b_tmp = - imgSrc_gy[pi[valid, 0], pj[valid, 0], :]
elif n == 3:
b_tmp = imgSrc_gy[pi[valid, 0] - 1, pj[valid, 0], :]
I = np.concatenate((I, I_tmp))
J = np.concatenate((J, J_tmp))
S = np.concatenate((S, S_tmp))
b = np.concatenate((b, b_tmp))
S_tmp = - np.ones(J_tmp.shape, dtype=np.float32)
J_tmp = qind[valid, n, None]
I = np.concatenate((I, I_tmp))
J = np.concatenate((J, J_tmp))
S = np.concatenate((S, S_tmp))
return I, J, S, b, e_start, e_stop
def gradient_mask(mask): #产生梯度的mask
gradient_mask = np.logical_or.reduce((mask,
np.concatenate((mask[1:, :], np.zeros((1, mask.shape[1]), dtype=np.bool)), axis=0),
np.concatenate((mask[:, 1:], np.zeros((mask.shape[0], 1), dtype=np.bool)), axis=1)))
return gradient_mask
if __name__ == '__main__':
import cvbase
from skimage.feature import canny
import argparse
import imageio
parser = argparse.ArgumentParser()
parser.add_argument('--flow', type=str, default='../../test_blending/flow/00000.flo')
parser.add_argument('--mask', type=str, default='../../test_blending/mask/00000.png')
parser.add_argument('--width', type=int, default=432)
parser.add_argument('--height', type=int, default=256)
parser.add_argument('--output', type=str, default='../../test_blending/ret')
args = parser.parse_args()
flow, mask = args.flow, args.mask
width, height = args.width, args.height
output = args.output
if not os.path.exists(output):
os.makedirs(output)
flow = cvbase.read_flow(flow)
mask = cv2.imread(mask, 0)
h, w, c = flow.shape
flow_resized = np.zeros((height, width, 2))
flow_resized[:, :, 0] = cv2.resize(flow[:, :, 0], (width, height), cv2.INTER_LINEAR) * width / w
flow_resized[:, :, 1] = cv2.resize(flow[:, :, 1], (width, height), cv2.INTER_LINEAR) * height / h
flow = flow_resized
mask = cv2.resize(mask, (width, height), cv2.INTER_NEAREST)
mask_gradient = gradient_mask(mask)
flow_gray = (flow[:, :, 0] ** 2 + flow[:, :, 1] ** 2) ** 0.5
flow_gray = flow_gray / flow_gray.max()
edge = canny(flow_gray, sigma=1, low_threshold=0.1, high_threshold=0.2)
edge = edge.astype(np.bool)
masked_edge = edge * mask
# gradients
gradient_x = np.concatenate((np.diff(flow, axis=1), np.zeros((height, 1, 2), dtype=np.float32)), axis=1)
gradient_y = np.concatenate((np.diff(flow, axis=0), np.zeros((1, width, 2), dtype=np.float32)), axis=0)
gradient = np.concatenate((gradient_x, gradient_y), axis=2)
gradient[mask_gradient, :] = 0 # 把中间的梯度设置成了0
# complete flow
imgSrc_gy = gradient[:, :, 2: 4]
imgSrc_gy = imgSrc_gy[0: h - 1, :, :]
imgSrc_gx = gradient[:, :, 0: 2]
imgSrc_gx = imgSrc_gx[:, 0: w - 1, :]
compFlow = Poisson_blend(flow, imgSrc_gx, imgSrc_gy, mask, masked_edge) # todo: edge or masked_edge ?
# save flow
flow_n = cvbase.flow2rgb(flow)
compFlow_n = cvbase.flow2rgb(compFlow)
imageio.imwrite(os.path.join(output, 'flow.png'), flow_n)
imageio.imwrite(os.path.join(output, 'compFlow.png'), compFlow_n)
imageio.imwrite(os.path.join(output, 'edge.png'), masked_edge)
# imageio.imwrite(os.path.join(output, 'gx.png'), imgSrc_gx)
# imageio.imwrite(os.path.join(output, 'gy.png'), imgSrc_gy)
imageio.imwrite(os.path.join(output, 'mask.png'), mask)
imageio.imwrite(os.path.join(output, 'grad0.png'), gradient[:, :, 0])
imageio.imwrite(os.path.join(output, 'grad1.png'), gradient[:, :, 1])