skimage2.transform.hough_line#

skimage2.transform.hough_line(image, theta=None)[source]#

Perform a straight line Hough transform.

Parameters:

imagendarray of shape (M, N): Input image with nonzero values representing edges.
thetandarray of double, shape (K,), optional: Angles at which to compute the transform, in radians. Defaults to a vector of 180 angles evenly spaced in the range [-pi/2, pi/2).

Returns:

hspacendarray of uint64, shape (P, Q): Hough transform accumulator.
anglesndarray: Angles at which the transform is computed, in radians.
distancesndarray: Distance values.

Notes

The origin is the top left corner of the original image. X and Y axis are horizontal and vertical edges respectively. The distance is the minimal algebraic distance from the origin to the detected line. The angle accuracy can be improved by decreasing the step size in the theta array.

Examples

Generate a test image:

>>> img = np.zeros((100, 150), dtype=bool)
>>> img[30, :] = 1
>>> img[:, 65] = 1
>>> img[35:45, 35:50] = 1
>>> for i in range(90):
...     img[i, i] = 1
>>> rng = np.random.default_rng()
>>> img += rng.random(img.shape) > 0.95

Apply the Hough transform:

>>> out, angles, d = hough_line(img)