mirror of
https://github.com/wassname/scikit-image.git
synced 2026-06-28 03:19:12 +08:00
Johannes Schönberger
45 lines
1.0 KiB
Cython
45 lines
1.0 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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cimport numpy as cnp
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cdef float integrate(cnp.ndarray[float, ndim=2, mode="c"] sat,
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int r0, int c0, int r1, int c1):
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"""
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Using a summed area table / integral image, calculate the sum
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over a given window.
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This function is the same as the `integrate` function in
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`skimage.transform.integrate`, but this Cython version significantly
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speeds up the code.
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Parameters
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----------
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sat : ndarray of float
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Summed area table / integral image.
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r0, c0 : int
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Top-left corner of block to be summed.
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r1, c1 : int
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Bottom-right corner of block to be summed.
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Returns
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-------
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S : int
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Sum over the given window.
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"""
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cdef float S = 0
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S += sat[r1, c1]
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if (r0 - 1 >= 0) and (c0 - 1 >= 0):
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S += sat[r0 - 1, c0 - 1]
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if (r0 - 1 >= 0):
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S -= sat[r0 - 1, c1]
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if (c0 - 1 >= 0):
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S -= sat[r1, c0 - 1]
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return S
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