mirror of
https://github.com/wassname/scikit-image.git
synced 2026-08-12 12:30:16 +08:00
66 lines
1.9 KiB
Cython
66 lines
1.9 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 numpy as np
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import cython
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ctypedef fused image_t:
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cython.uchar[:, :]
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cython.double[:, :]
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cpdef moments_central(image_t image, double cr, double cc, Py_ssize_t order):
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cdef Py_ssize_t p, q, r, c
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cdef double[:, ::1] mu = np.zeros((order + 1, order + 1), dtype=np.double)
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cdef double val, dr, dc, dcp, drq
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for r in range(image.shape[0]):
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dr = r - cr
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for c in range(image.shape[1]):
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dc = c - cc
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val = image[r, c]
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dcp = 1
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for p in range(order + 1):
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drq = 1
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for q in range(order + 1):
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mu[p, q] += val * drq * dcp
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drq *= dr
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dcp *= dc
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return np.asarray(mu)
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def moments_normalized(double[:, :] mu, Py_ssize_t order=3):
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cdef Py_ssize_t p, q
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cdef double[:, ::1] nu = np.zeros((order + 1, order + 1), dtype=np.double)
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for p in range(order + 1):
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for q in range(order + 1):
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if p + q >= 2:
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nu[p, q] = mu[p, q] / mu[0, 0] ** (<double>(p + q) / 2 + 1)
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else:
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nu[p, q] = np.nan
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return np.asarray(nu)
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def moments_hu(double[:, :] nu):
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cdef double[::1] hu = np.zeros((7, ), dtype=np.double)
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cdef double t0 = nu[3, 0] + nu[1, 2]
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cdef double t1 = nu[2, 1] + nu[0, 3]
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cdef double q0 = t0 * t0
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cdef double q1 = t1 * t1
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cdef double n4 = 4 * nu[1, 1]
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cdef double s = nu[2, 0] + nu[0, 2]
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cdef double d = nu[2, 0] - nu[0, 2]
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hu[0] = s
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hu[1] = d * d + n4 * nu[1, 1]
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hu[3] = q0 + q1
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hu[5] = d * (q0 - q1) + n4 * t0 * t1
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t0 *= q0 - 3 * q1
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t1 *= 3 * q0 - q1
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q0 = nu[3, 0]- 3 * nu[1, 2]
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q1 = 3 * nu[2, 1] - nu[0, 3]
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hu[2] = q0 * q0 + q1 * q1
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hu[4] = q0 * t0 + q1 * t1
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hu[6] = q1 * t0 - q0 * t1
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return np.asarray(hu)
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