mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-28 15:40:22 +08:00
bennlich
170 lines
5.1 KiB
Python
170 lines
5.1 KiB
Python
# coding: utf-8
|
|
import numpy as np
|
|
from ._draw import _coords_inside_image
|
|
|
|
|
|
def _ellipse_in_shape(shape, center, radiuses):
|
|
"""Generate coordinates of points within ellipse bounded by shape."""
|
|
y, x = np.ogrid[0:float(shape[0]), 0:float(shape[1])]
|
|
cy, cx = center
|
|
ry, rx = radiuses
|
|
distances = ((y - cy) / ry) ** 2 + ((x - cx) / rx) ** 2
|
|
return np.nonzero(distances < 1)
|
|
|
|
|
|
def ellipse(cy, cx, yradius, xradius, shape=None):
|
|
"""Generate coordinates of pixels within ellipse.
|
|
|
|
Parameters
|
|
----------
|
|
cy, cx : double
|
|
Centre coordinate of ellipse.
|
|
yradius, xradius : double
|
|
Minor and major semi-axes. ``(x/xradius)**2 + (y/yradius)**2 = 1``.
|
|
shape : tuple, optional
|
|
Image shape which is used to determine the maximum extent of output pixel
|
|
coordinates. This is useful for ellipses which exceed the image size.
|
|
By default the full extent of the ellipse are used.
|
|
|
|
Returns
|
|
-------
|
|
rr, cc : ndarray of int
|
|
Pixel coordinates of ellipse.
|
|
May be used to directly index into an array, e.g.
|
|
``img[rr, cc] = 1``.
|
|
|
|
Examples
|
|
--------
|
|
>>> from skimage.draw import ellipse
|
|
>>> img = np.zeros((10, 10), dtype=np.uint8)
|
|
>>> rr, cc = ellipse(5, 5, 3, 4)
|
|
>>> img[rr, cc] = 1
|
|
>>> img
|
|
array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
|
|
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
|
|
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
|
|
[0, 0, 0, 1, 1, 1, 1, 1, 0, 0],
|
|
[0, 0, 1, 1, 1, 1, 1, 1, 1, 0],
|
|
[0, 0, 1, 1, 1, 1, 1, 1, 1, 0],
|
|
[0, 0, 1, 1, 1, 1, 1, 1, 1, 0],
|
|
[0, 0, 0, 1, 1, 1, 1, 1, 0, 0],
|
|
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
|
|
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
|
|
|
|
"""
|
|
|
|
center = np.array([cy, cx])
|
|
radiuses = np.array([yradius, xradius])
|
|
|
|
# The upper_left and lower_right corners of the
|
|
# smallest rectangle containing the ellipse.
|
|
upper_left = np.ceil(center - radiuses).astype(int)
|
|
lower_right = np.floor(center + radiuses).astype(int)
|
|
|
|
if shape is not None:
|
|
# Constrain upper_left and lower_right by shape boundary.
|
|
upper_left = np.maximum(upper_left, np.array([0, 0]))
|
|
lower_right = np.minimum(lower_right, np.array(shape[:2]) - 1)
|
|
|
|
shifted_center = center - upper_left
|
|
bounding_shape = lower_right - upper_left + 1
|
|
|
|
rr, cc = _ellipse_in_shape(bounding_shape, shifted_center, radiuses)
|
|
rr.flags.writeable = True
|
|
cc.flags.writeable = True
|
|
rr += upper_left[0]
|
|
cc += upper_left[1]
|
|
return rr, cc
|
|
|
|
|
|
def circle(cy, cx, radius, shape=None):
|
|
"""Generate coordinates of pixels within circle.
|
|
|
|
Parameters
|
|
----------
|
|
cy, cx : double
|
|
Centre coordinate of circle.
|
|
radius: double
|
|
Radius of circle.
|
|
shape : tuple, optional
|
|
Image shape which is used to determine the maximum extent of output pixel
|
|
coordinates. This is useful for circles which exceed the image size.
|
|
By default the full extent of the circle are used.
|
|
|
|
Returns
|
|
-------
|
|
rr, cc : ndarray of int
|
|
Pixel coordinates of circle.
|
|
May be used to directly index into an array, e.g.
|
|
``img[rr, cc] = 1``.
|
|
|
|
Notes
|
|
-----
|
|
This function is a wrapper for skimage.draw.ellipse()
|
|
|
|
Examples
|
|
--------
|
|
>>> from skimage.draw import circle
|
|
>>> img = np.zeros((10, 10), dtype=np.uint8)
|
|
>>> rr, cc = circle(4, 4, 5)
|
|
>>> img[rr, cc] = 1
|
|
>>> img
|
|
array([[0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
|
|
[0, 1, 1, 1, 1, 1, 1, 1, 0, 0],
|
|
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
|
|
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
|
|
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
|
|
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
|
|
[1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
|
|
[0, 1, 1, 1, 1, 1, 1, 1, 0, 0],
|
|
[0, 0, 1, 1, 1, 1, 1, 0, 0, 0],
|
|
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]], dtype=uint8)
|
|
|
|
"""
|
|
|
|
return ellipse(cy, cx, radius, radius, shape)
|
|
|
|
|
|
def set_color(img, coords, color):
|
|
"""Set pixel color in the image at the given coordinates.
|
|
|
|
Coordinates that exceed the shape of the image will be ignored.
|
|
|
|
Parameters
|
|
----------
|
|
img : (M, N, D) ndarray
|
|
Image
|
|
coords : ((P,) ndarray, (P,) ndarray)
|
|
Coordinates of pixels to be colored.
|
|
color : (D,) ndarray
|
|
Color to be assigned to coordinates in the image.
|
|
|
|
Returns
|
|
-------
|
|
img : (M, N, D) ndarray
|
|
The updated image.
|
|
|
|
Examples
|
|
--------
|
|
>>> from skimage.draw import line, set_color
|
|
>>> img = np.zeros((10, 10), dtype=np.uint8)
|
|
>>> rr, cc = line(1, 1, 20, 20)
|
|
>>> set_color(img, (rr, cc), 1)
|
|
>>> img
|
|
array([[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
|
|
[0, 1, 0, 0, 0, 0, 0, 0, 0, 0],
|
|
[0, 0, 1, 0, 0, 0, 0, 0, 0, 0],
|
|
[0, 0, 0, 1, 0, 0, 0, 0, 0, 0],
|
|
[0, 0, 0, 0, 1, 0, 0, 0, 0, 0],
|
|
[0, 0, 0, 0, 0, 1, 0, 0, 0, 0],
|
|
[0, 0, 0, 0, 0, 0, 1, 0, 0, 0],
|
|
[0, 0, 0, 0, 0, 0, 0, 1, 0, 0],
|
|
[0, 0, 0, 0, 0, 0, 0, 0, 1, 0],
|
|
[0, 0, 0, 0, 0, 0, 0, 0, 0, 1]], dtype=uint8)
|
|
|
|
"""
|
|
|
|
rr, cc = coords
|
|
rr, cc = _coords_inside_image(rr, cc, img.shape)
|
|
img[rr, cc] = color
|