"gaussian pyramid de- and re-construction"

def __init__(self, level=7, size=(1920,1200)):

self.level = level

self.size = size

def down_size(self):

divisor = float(pow(2, self.level))

w = int(numpy.ceil(self.size[0] / divisor))

h = int(numpy.ceil(self.size[1] / divisor))

return (w,h)

def down(self, im):

"reduce `im' to self.level"

for iteration in range(self.level):

im = cv2.pyrDown(im)

return im

def up(self, im):

"assume `im' is at self.level & restore"

for level in reversed(range(self.level)):

# make sure we get back to the original size exactly

divisor = float(pow(2, level))

w = int(numpy.ceil(self.size[0] / divisor))

h = int(numpy.ceil(self.size[1] / divisor))

if len(im.shape)>2:

shape = (h,w,im.shape[2])

else:

shape = (h,w)

z = numpy.zeros(shape, dtype=numpy.uint8)

cv2.pyrUp(im, z, (w,h))

im = z

"constraint generation & iteration s.t. no pixel has two ``on'' edges"

def __init__(self, size=(15,10)):

self.size = size

self._modidx = 0

def last(self):

self._modidx = (self._modidx - 1) % 5

return self.next()

def prev(self):

self._modidx = (self._modidx - 2) % 5

return self.next()

def next(self):

"return a constraint that should limit deltaCorrection"

c = numpy.zeros((self.size[1], self.size[0]), dtype=numpy.bool)

for idx in range(self.size[1]):

i = (2*idx + self._modidx) % 5

c[idx,i::5] = True

self._modidx = (self._modidx + 1) % 5

return c