def ssim(img1, img2, cs_map=False):
"""Return the Structural Similarity Map corresponding to input images img1
and img2 (images are assumed to be uint8)
This function attempts to mimic precisely the functionality of ssim.m a
MATLAB provided by the author's of SSIM
https://ece.uwaterloo.ca/~z70wang/research/ssim/ssim_index.m
"""
img1 = img1.astype(numpy.float64)
img2 = img2.astype(numpy.float64)
size = 11
sigma = 1.5
window = gauss.fspecial_gauss(size, sigma)
K1 = 0.01
K2 = 0.03
L = 255 #bitdepth of image
C1 = (K1*L)**2
C2 = (K2*L)**2
mu1 = signal.fftconvolve(window, img1, mode='valid')
mu2 = signal.fftconvolve(window, img2, mode='valid')
mu1_sq = mu1*mu1
mu2_sq = mu2*mu2
mu1_mu2 = mu1*mu2
sigma1_sq = signal.fftconvolve(window, img1*img1, mode='valid') - mu1_sq
sigma2_sq = signal.fftconvolve(window, img2*img2, mode='valid') - mu2_sq
sigma12 = signal.fftconvolve(window, img1*img2, mode='valid') - mu1_mu2
if cs_map:
return (((2*mu1_mu2 + C1)*(2*sigma12 + C2))/((mu1_sq + mu2_sq + C1)*
(sigma1_sq + sigma2_sq + C2)),
(2.0*sigma12 + C2)/(sigma1_sq + sigma2_sq + C2))
else:
return ((2*mu1_mu2 + C1)*(2*sigma12 + C2))/((mu1_sq + mu2_sq + C1)*
(sigma1_sq + sigma2_sq + C2))
def ssim(img1, img2, cs_map=False):
"""Return the Structural Similarity Map corresponding to input images img1
and img2 (images are assumed to be uint8)
This function attempts to mimic precisely the functionality of ssim.m a
MATLAB provided by the author's of SSIM
https://ece.uwaterloo.ca/~z70wang/research/ssim/ssim_index.m
"""
img1 = img1.astype(numpy.float64)
img2 = img2.astype(numpy.float64)
size = 11
sigma = 1.5
window = gauss.fspecial_gauss(size, sigma)
K1 = 0.01
K2 = 0.03
L = 255 #bitdepth of image
C1 = (K1 * L)**2
C2 = (K2 * L)**2
mu1 = signal.fftconvolve(window, img1, mode='valid')
mu2 = signal.fftconvolve(window, img2, mode='valid')
mu1_sq = mu1 * mu1
mu2_sq = mu2 * mu2
mu1_mu2 = mu1 * mu2
sigma1_sq = signal.fftconvolve(window, img1 * img1, mode='valid') - mu1_sq
sigma2_sq = signal.fftconvolve(window, img2 * img2, mode='valid') - mu2_sq
sigma12 = signal.fftconvolve(window, img1 * img2, mode='valid') - mu1_mu2
if cs_map:
return (((2 * mu1_mu2 + C1) * (2 * sigma12 + C2)) /
((mu1_sq + mu2_sq + C1) * (sigma1_sq + sigma2_sq + C2)),
(2.0 * sigma12 + C2) / (sigma1_sq + sigma2_sq + C2))
else:
return ((2 * mu1_mu2 + C1) *
(2 * sigma12 + C2)) / ((mu1_sq + mu2_sq + C1) *
(sigma1_sq + sigma2_sq + C2))
def ssim(img1, img2, cs_map=False):
"""Return the Structural Similarity Map corresponding to input images img1
and img2 (images are assumed to be uint8)
"""
img1 = img1.astype(numpy.float64)
img2 = img2.astype(numpy.float64)
size = 11
sigma = 1.5
window = gauss.fspecial_gauss(size, sigma)
K1 = 0.01
K2 = 0.03
L = 255 #bitdepth of image
C1 = (K1*L)**2
C2 = (K2*L)**2
mu1 = signal.fftconvolve(window, img1, mode='valid')
mu2 = signal.fftconvolve(window, img2, mode='valid')
mu1_sq = mu1*mu1
mu2_sq = mu2*mu2
mu1_mu2 = mu1*mu2
sigma1_sq = signal.fftconvolve(window, img1*img1, mode='valid') - mu1_sq
sigma2_sq = signal.fftconvolve(window, img2*img2, mode='valid') - mu2_sq
sigma12 = signal.fftconvolve(window, img1*img2, mode='valid') - mu1_mu2
if cs_map:
return (((2*mu1_mu2 + C1)*(2*sigma12 + C2))/((mu1_sq + mu2_sq + C1)*
(sigma1_sq + sigma2_sq + C2)),
(2.0*sigma12 + C2)/(sigma1_sq + sigma2_sq + C2))
else:
return ((2*mu1_mu2 + C1)*(2*sigma12 + C2))/((mu1_sq + mu2_sq + C1)*
(sigma1_sq + sigma2_sq + C2))
def ssim(self, img1, img2, cs_map=False):
img1 = img1.astype(np.float64)
img2 = img2.astype(np.float64)
size = 11
sigma = 1.5
window = gauss.fspecial_gauss(size, sigma)
K1 = 0.01
K2 = 0.03
L = 255 #bitdepth of image
C1 = (K1 * L)**2
C2 = (K2 * L)**2
mu1 = signal.fftconvolve(window, img1, mode='valid')
mu2 = signal.fftconvolve(window, img2, mode='valid')
mu1_sq = mu1 * mu1
mu2_sq = mu2 * mu2
mu1_mu2 = mu1 * mu2
sigma1_sq = signal.fftconvolve(window, img1 * img1,
mode='valid') - mu1_sq
sigma2_sq = signal.fftconvolve(window, img2 * img2,
mode='valid') - mu2_sq
sigma12 = signal.fftconvolve(window, img1 * img2,
mode='valid') - mu1_mu2
if cs_map:
return (((2 * mu1_mu2 + C1) * (2 * sigma12 + C2)) /
((mu1_sq + mu2_sq + C1) * (sigma1_sq + sigma2_sq + C2)),
(2.0 * sigma12 + C2) / (sigma1_sq + sigma2_sq + C2))
else:
return ((2 * mu1_mu2 + C1) *
(2 * sigma12 + C2)) / ((mu1_sq + mu2_sq + C1) *
(sigma1_sq + sigma2_sq + C2))
def ssim(cover, stego, cs_map=False):
if not cs_map:
cover = rgb2gray(np.array(cover)).astype(np.float64)
stego = rgb2gray(np.array(stego)).astype(np.float64)
size = 11
sigma = 1.5
window = gauss.fspecial_gauss(size, sigma)
K1 = 0.01
K2 = 0.03
L = 255 #bitdepth of image
C1 = (K1 * L)**2
C2 = (K2 * L)**2
mu1 = signal.fftconvolve(cover, window, mode='valid')
mu2 = signal.fftconvolve(stego, window, mode='valid')
# mu1 = signal.fftconvolve(window, cover, mode='valid')
# mu2 = signal.fftconvolve(window, stego, mode='valid')
mu1_sq = mu1 * mu1
mu2_sq = mu2 * mu2
mu1_mu2 = mu1 * mu2
sigma1_sq = signal.fftconvolve(cover * cover, window,
mode='valid') - mu1_sq
sigma2_sq = signal.fftconvolve(stego * stego, window,
mode='valid') - mu2_sq
sigma12 = signal.fftconvolve(cover * stego, window, mode='valid') - mu1_mu2
# sigma1_sq = signal.fftconvolve(window, cover*cover, mode='valid') - mu1_sq
# sigma2_sq = signal.fftconvolve(window, stego*stego, mode='valid') - mu2_sq
# sigma12 = signal.fftconvolve(window, cover*stego, mode='valid') - mu1_mu2
if cs_map:
return (((2 * mu1_mu2 + C1) * (2 * sigma12 + C2)) /
((mu1_sq + mu2_sq + C1) * (sigma1_sq + sigma2_sq + C2)),
(2.0 * sigma12 + C2) / (sigma1_sq + sigma2_sq + C2))
else:
return np.mean(((2 * mu1_mu2 + C1) * (2 * sigma12 + C2)) /
((mu1_sq + mu2_sq + C1) * (sigma1_sq + sigma2_sq + C2)))
