mirror of
https://github.com/wassname/scikit-image.git
synced 2026-07-12 07:29:48 +08:00
Ankit Agrawal
36 lines
1.3 KiB
Python
36 lines
1.3 KiB
Python
import numpy as np
|
|
from ..util import img_as_float
|
|
|
|
|
|
def corner_fast(image, n=9, threshold=0.15):
|
|
|
|
image = np.squeeze(image)
|
|
if image.ndim != 2:
|
|
raise ValueError("Only 2-D gray-scale images supported.")
|
|
|
|
image = img_as_float(image)
|
|
corner_mask = np.zeros(image.shape, dtype=bool)
|
|
|
|
test_pixels = np.asarray([[-3, 0], [-3, 1], [-2, 2], [-1, 3], [0, 3],
|
|
[1, 3], [2, 2], [3, 1], [3, 0], [3, -1],
|
|
[2, -2], [1, -3], [0, -3], [-1, -3],
|
|
[-2, -2], [-1, -3]])
|
|
|
|
# TODO : Outsource to Cython
|
|
for i in range(3, image.shape[0] - 3):
|
|
for j in range(3, image.shape[1] - 3):
|
|
test_x = i + test_pixels[:, 0]
|
|
test_y = j + test_pixels[:, 1]
|
|
intensities = image[test_x, test_y]
|
|
low = intensities < image[i, j] - threshold
|
|
high = intensities > image[i, j] + threshold
|
|
low = np.concatenate(low, low)
|
|
high = np.concatenate(high, high)
|
|
# How to check if a sequence n * [True] exists in low/high ?
|
|
# if n * [True] in low or n * True in high:
|
|
# corner_mask[i, j] = True
|
|
|
|
corner_x, corner_y = np.where(corner_mask == True)
|
|
corners = np.dstack(corner_x, corner_y)
|
|
return corners
|