def extractmsg(sed, im, perc):
total = 0.0
w,h = im.size
size = w * h
se = rand_sequece(sed, int(size*perc), True)
rand_list = random_walk(sed, size, size-1)
r = get_gauss_seq(sed, size-1, 0, 1.5, 5)
s = get_gauss_seq(2+sed, size-1, 0, 1.5, 5)
i = 0
j = 0
while i < len(se):
while True:
x = rand_list[i+j] / w
y = rand_list[i+j] % w
pixel = im.getpixel((x, y))
# k = 0
if not parity_func(pixel, r[i+j]-s[i+j]):
j += 1
continue
elif parity_func(pixel, r[i+j]-s[i+j]) == se[i]:
total += 1
break
else:
break
i+=1
print "Extract pixel:%d" %(i+j)
print "Total:%d Extract Percent:%f" %(total, total/(size*perc))
def extratlsb(sed, im, perc):
w,h = im.size
size = w * h
se = rand_sequece(sed, int(size * perc), False)
origin_list = random_walk(sed, size, len(se))
sim = 0
for s, r in zip(se, origin_list):
x = r / w
y = r % w
pixel = im.getpixel((x, y))
if pixel & 1 == s:
sim += 1
return sim / float(len(se))
def lsb_replace(sed, im, perc):
nim = im.copy()
w,h = im.size
size = w * h
se = rand_sequece(sed, int(size * perc), False)
rand_list = random_walk(sed, w*h, int(size * perc))
s = set(rand_list);
for s, r in zip(se, rand_list):
x = r / w;
y = r % w;
pixel = nim.getpixel((x, y))
pixel = (pixel & 0xfe) | s
nim.putpixel((x, y), pixel);
fn = (re.search("[0-9]*\.(.*)", im.filename)).group(0)
path = 'result/' + im.format + '/' + str(perc) + '_' + fn
nim.save(path) #profile needed to store otherwise the brightness would not same.
return nim, path
def embedmsg(sed, im, perc):
nim = im.copy()
w,h = nim.size
size = w * h
msglen = int(size * perc)
rand_list = random_walk(sed, size, size-1)
se = rand_sequece(sed, msglen, True)
print "Len :%d" %len(se)
r = get_gauss_seq(sed, size-1, 0, 1.5, 5)
s = get_gauss_seq(2+sed, size-1, 0, 1.5, 5)
i = 0
# j is used to hide message when k = 0 and find next pos.
j = 0
# Add
while i < len(se):
while True:
x = rand_list[i+j] / w
y = rand_list[i+j] % w
pixel = nim.getpixel((x, y))
k = r[i+j] - s[i+j]
# k = 0 then pixel = x+r
if not parity_func(pixel + r[i+j], k):
pixel = checkbound(pixel, r[i+j], k, se[i])
nim.putpixel((x,y), pixel)
j += 1
continue
elif parity_func(pixel + r[i+j], k) == se[i]:
pixel = checkbound(pixel, r[i+j], k, se[i])
nim.putpixel((x,y), pixel)
break
else:
pixel = checkbound(pixel, s[i+j], k, se[i])
nim.putpixel((x,y), pixel)
break
i += 1;
print "embeded pixel:%d" %(i+j)
fn = (re.search("[0-9]*\.(.*)", im.filename)).group(0)
path = 'result_stm/' + im.format + '/' + str(perc) + '_' + fn
nim.save(path) #profile needed to store otherwise the brightness would not same.
return nim, path
for s, r in zip(se, origin_list):
x = r / w
y = r % w
pixel = im.getpixel((x, y))
if pixel & 1 == s:
sim += 1
return sim / float(len(se))
if __name__ == "__main__":
y1 = []
y2 = []
y3 = []
im = Image.open("test_images/png/1.png")
fn,path = lsb_replace(3, im, 0.5)
print rand_sequece(1, 100, True)
print extratlsb(3, fn, 0.5)
y1.append(sample_analyze(fn))
im.close()
fn.close()
'''
for i in getallfile('test_images/jpeg/'):
im = Image.open(i)
fn = lsb_replace(3, im, 0.5)
fn1 = lsb_replace(3, im, 0.25)
fn2 = lsb_replace(3, im, 0.05)
y1.append(sample_analyze(fn))
y2.append(sample_analyze(fn1))
y3.append(sample_analyze(fn2))
im.close()
fn.close()