def array2pil(a):
if a.dtype==dtype("B"):
if a.ndim==2:
return PIL.Image.frombytes("L",(a.shape[1],a.shape[0]),a.tostring())
elif a.ndim==3:
return PIL.Image.frombytes("RGB",(a.shape[1],a.shape[0]),a.tostring())
else:
raise OcropusException("bad image rank")
elif a.dtype==dtype('float32'):
return PIL.Image.fromstring("F",(a.shape[1],a.shape[0]),a.tostring())
else:
raise OcropusException("unknown image type")
def read_image_gray(fname, pageno=0):
"""Read an image and returns it as a floating point array.
The optional page number allows images from files containing multiple
images to be addressed. Byte and short arrays are rescaled to
the range 0...1 (unsigned) or -1...1 (signed)."""
if type(fname) == tuple: fname, pageno = fname
assert pageno == 0
if issubclass(type(fname), PIL.Image.Image):
pil = fname
else:
pil = PIL.Image.open(fname)
a = pil2array(pil)
if a.dtype == dtype('uint8'):
a = a / 255.0
if a.dtype == dtype('int8'):
a = a / 127.0
elif a.dtype == dtype('uint16'):
a = a / 65536.0
elif a.dtype == dtype('int16'):
a = a / 32767.0
elif isfloatarray(a):
pass
else:
raise OcropusException("unknown image type: " + a.dtype)
if a.ndim == 3:
a = mean(a, 2)
return a
