DTYPES = [np.uint8, np.float] # (etc...)

def do_stuff(np.ndarray[dtype=DTYPES, ndim=2], img):

	cdef (some vars)

	cdef DTYPES pixel

	for i in range(rows):
		for j in range(cols):

			pixel = img[i, j]

			if DTYPES == np.uint8:
				<<datatype specific stuff>>

			<<other stuff>>



** run the templater to produce this output: **

def do_stuff_uint8(np.ndarray[dtype=np.uint8, ndim=2], img):

	cdef (some vars)

	cdef np.uint8 pixel

	for i in range(rows):
		for j in range(cols):

			pixel = img[i, j]

			<<datatype specific stuff>>

			<<other stuff>>


def do_stuff_float(np.ndarray[dtype=np.float, ndim=2], img):

	cdef (some vars)

	cdef np.float pixel

	for i in range(rows):
		for j in range(cols):

			pixel = img[i, j]

			<<other stuff>>


def do_stuff(np.ndarray img):
	if img.dtype == np.uint8:
		do_stuff_uint8(img)
	elif img.dtype == np.float:
		do_stuff_float(img)
	else:
		pass