mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-27 18:25:32 +08:00
Johannes Schönberger
58 lines
1.7 KiB
Cython
58 lines
1.7 KiB
Cython
#cython: cdivision=True
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#cython: boundscheck=False
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#cython: nonecheck=False
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#cython: wraparound=False
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import os
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import numpy as np
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from .. import data_dir
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cimport numpy as cnp
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from libc.math cimport sin, cos
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from .._shared.interpolation cimport round
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POS = np.loadtxt(os.path.join(data_dir, "orb_descriptor_positions.txt"),
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dtype=np.int8)
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POS0 = np.ascontiguousarray(POS[:, :2])
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POS1 = np.ascontiguousarray(POS[:, 2:])
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def _orb_loop(double[:, ::1] image, Py_ssize_t[:, ::1] keypoints,
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double[:] orientations):
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cdef Py_ssize_t i, d, kr, kc, pr0, pr1, pc0, pc1, spr0, spc0, spr1, spc1
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cdef int[:, ::1] steered_pos0, steered_pos1
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cdef double angle
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cdef unsigned char[:, ::1] descriptors = \
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np.zeros((keypoints.shape[0], POS.shape[0]), dtype=np.uint8)
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cdef signed char[:, ::1] cpos0 = POS0
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cdef signed char[:, ::1] cpos1 = POS1
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with nogil:
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for i in range(descriptors.shape[0]):
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angle = orientations[i]
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sin_a = sin(angle)
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cos_a = cos(angle)
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kr = keypoints[i, 0]
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kc = keypoints[i, 1]
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for j in range(descriptors.shape[1]):
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pr0 = cpos0[j, 0]
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pc0 = cpos0[j, 1]
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pr1 = cpos1[j, 0]
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pc1 = cpos1[j, 1]
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spr0 = <Py_ssize_t>round(sin_a * pr0 + cos_a * pc0)
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spc0 = <Py_ssize_t>round(cos_a * pr0 - sin_a * pc0)
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spr1 = <Py_ssize_t>round(sin_a * pr1 + cos_a * pc1)
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spc1 = <Py_ssize_t>round(cos_a * pr1 - sin_a * pc1)
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if image[kr + spr0, kc + spc0] < image[kr + spr1, kc + spc1]:
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descriptors[i, j] = True
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return np.asarray(descriptors)
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