diff --git a/skimage/feature/censure.py b/skimage/feature/censure.py index d0ac94a9..179eac70 100644 --- a/skimage/feature/censure.py +++ b/skimage/feature/censure.py @@ -49,6 +49,15 @@ def _get_filtered_image(image, n_scales, mode): _octagon_filter(outer_shape[i][0], outer_shape[i][1], inner_shape[i][0], inner_shape[i][1])) + else: + shape = [1, 2, 3, 4, 6, 8, 11, 12, 16, 22, 23, 32, 45, 46, 64, 90, + 128] + filter_shape = [(1, 0), (3, 1), (4, 2), (5, 3), (7, 4), (8, 5), + (9, 6),(11, 8), (13, 10), (14, 11), (15, 12), (16, 14)] + for i in range(n_scales): + scales[:, :, i] = convolve(image, + _star_filter(shape[filter_shape[i][0]], + shape[filter_shape[i][1]])) return scales @@ -70,13 +79,46 @@ def _oct(m, n): def _octagon_filter(mo, no, mi, ni): outer = (mo + 2 * no)**2 - 2 * no * (no + 1) inner = (mi + 2 * ni)**2 - 2 * ni * (ni + 1) - outer_wt = 1.0 / (outer - inner) - inner_wt = 1.0 / inner + outer_weight = 1.0 / (outer - inner) + inner_weight = 1.0 / inner c = ((mo + 2 * no) - (mi + 2 * ni)) / 2 outer_oct = _oct(mo, no) inner_oct = np.zeros((mo + 2 * no, mo + 2 * no)) - inner_oct[c:-c, c:-c] = _oct(mi, ni) - bfilter = outer_wt * outer_oct - (outer_wt + inner_wt) * inner_oct + inner_oct[c: -c, c: -c] = _oct(mi, ni) + bfilter = (outer_weight * outer_oct - + (outer_weight + inner_weight) * inner_oct) + return bfilter + + +def _star(a): + if a == 1: + bfilter = np.zeros((3, 3)) + bfilter[:] = 1 + return bfilter + m = 2 * a + 1 + n = a / 2 + selem_square = np.zeros((m + 2 * n, m + 2 * n), dtype=np.uint8) + selem_square[n: m + n, n: m + n] = 1 + selem_triangle = np.zeros((m + 2 * n, m + 2 * n), dtype=np.uint8) + selem_triangle[(m + 2 * n - 1) / 2, 0] = 1 + selem_triangle[(m + 1) / 2, n - 1] = 1 + selem_triangle[(m + 4 * n - 3) / 2, n - 1] = 1 + selem_triangle = convex_hull_image(selem_triangle).astype(int) + selem_triangle += selem_triangle[:, ::-1] + selem_triangle.T + selem_triangle.T[::-1, :] + return selem_square + selem_triangle + + +def _star_filter(m, n): + outer = 4 * m**2 + 4 * m + 1 + 4 * (m / 2)**2 + inner = 4 * n**2 + 4 * n + 1 + 4 * (n / 2)**2 + outer_weight = 1.0 / (outer - inner) + inner_weight = 1.0 / inner + c = m + m / 2 - n - n / 2 + outer_star = _star(m) + inner_star = np.zeros((outer_star.shape)) + inner_star[c: -c, c: -c] = _star(n) + bfilter = (outer_weight * outer_star - + (outer_weight + inner_weight) * inner_star) return bfilter @@ -106,7 +148,7 @@ def censure_keypoints(image, n_scales=7, mode='DoB', threshold=0.03, Number of scales to extract keypoints from. The keypoints will be extracted from all the scales except the first and the last. - mode : {'DoB', 'Octagon', 'STAR'} + mode : ('DoB', 'Octagon', 'STAR') Type of bilevel filter used to get the scales of input image. Possible values are 'DoB', 'Octagon' and 'STAR'.