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preallocated seam_buffer and added noil

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This commit is contained in:
Vighnesh Birodkar
2015-06-15 20:49:26 +05:30
parent 958f410a5c
commit fee667b35c
1 changed files with 15 additions and 9 deletions
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skimage/transform/_seam_carving.pyx
+15 -9
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@@ -8,10 +8,10 @@ cimport numpy as cnp
cdef cnp.double_t DBL_MAX = np.finfo(np.double).max
cdef _preprocess_image(cnp.double_t[:, :, ::1] energy_img,
cnp.double_t[:, ::1] cumulative_img,
cnp.int8_t[:, ::1] track_img,
Py_ssize_t cols):
cdef void _preprocess_image(cnp.double_t[:, :, ::1] energy_img,
cnp.double_t[:, ::1] cumulative_img,
cnp.int8_t[:, ::1] track_img,
Py_ssize_t cols) nogil:
""" For each row, compute the lowest seam value for all its columns.
This function updates `cumulative_img` such that `cumulative_img[r, c]`
@@ -60,7 +60,8 @@ cdef _preprocess_image(cnp.double_t[:, :, ::1] energy_img,
cdef cnp.uint8_t _mark_seam(cnp.int8_t[:, ::1] track_img,
Py_ssize_t start_index,
cnp.uint8_t[:, ::1] seam_map):
cnp.uint8_t[:, ::1] seam_map,
Py_ssize_t[::1] seam_buffer) nogil:
""" Re-trace the optimal seam from a given column in the last row.
@@ -77,6 +78,9 @@ cdef cnp.uint8_t _mark_seam(cnp.int8_t[:, ::1] track_img,
seam_map : (M, N) ndarray
The array used to mark seams. If a pixel is marked as as seam it is set
to `1`, else `0`.
seam_buffer : (M,) ndarray
Buffer used to store the column indices of the seam currently being
checked. This is preallocated to save time.
Returns
-------
@@ -84,7 +88,7 @@ cdef cnp.uint8_t _mark_seam(cnp.int8_t[:, ::1] track_img,
`1` if seam was marked, `0` is seam inersects and was not marked.
"""
cdef Py_ssize_t rows = track_img.shape[0]
cdef Py_ssize_t[::1] current_seam_indices = np.zeros(rows, dtype=np.int)
cdef Py_ssize_t[::1] current_seam_indices = seam_buffer
cdef Py_ssize_t row, col
cdef cnp.int8_t offset
cdef Py_ssize_t seams
@@ -105,8 +109,8 @@ cdef cnp.uint8_t _mark_seam(cnp.int8_t[:, ::1] track_img,
return 1
cdef _remove_seam(cnp.double_t[:, :, ::1] img,
cnp.uint8_t[:, ::1] seam_map, Py_ssize_t cols):
cdef void _remove_seam(cnp.double_t[:, :, ::1] img,
cnp.uint8_t[:, ::1] seam_map, Py_ssize_t cols) nogil:
""" Remove marked seams from an image.
Parameters
@@ -176,6 +180,7 @@ def _seam_carve_v(img, energy_map, iters, border):
cdef Py_ssize_t seams_left = iters
cdef Py_ssize_t seams_removed
cdef Py_ssize_t seam_idx
cdef Py_ssize_t[::1] seam_buffer = np.zeros(rows, dtype=np.int)
cdef cnp.double_t[:, :, ::1] image = img
cdef cnp.int8_t[:, ::1] track_img = np.zeros(img.shape[0:2], dtype=np.int8)
@@ -202,7 +207,8 @@ def _seam_carve_v(img, energy_map, iters, border):
seam_idx = 0
while seams_left > 0:
if _mark_seam(track_img, sorted_indices[seam_idx], seam_map):
if _mark_seam(track_img, sorted_indices[seam_idx], seam_map,
seam_buffer):
seams_left -= 1
cols -= 1
seam_idx += 1