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Add get_pixel function for 3D arrays

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This commit is contained in:
Johannes Schönberger
2012-10-05 23:09:34 +02:00
parent 25867b9dd5
commit 75d706ca25
2 changed files with 49 additions and 12 deletions
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skimage/_shared/interpolation.pxd
+5 -2
View File
@@ -18,7 +18,10 @@ cdef double bicubic_interpolation(double* image, int rows, int cols,
double r, double c, char mode,
double cval)
cdef double get_pixel(double* image, int rows, int cols, int r, int c,
char mode, double cval)
cdef double get_pixel2d(double* image, int rows, int cols, int r, int c,
char mode, double cval)
cdef double get_pixel3d(double* image, int rows, int cols, int dims, int r,
int c, int d, char mode, double cval)
cdef int coord_map(int dim, int coord, char mode)
skimage/_shared/interpolation.pyx
+44 -10
View File
@@ -35,8 +35,8 @@ cdef inline double nearest_neighbour_interpolation(double* image, int rows,
"""
return get_pixel(image, rows, cols, <int>round(r), <int>round(c),
mode, cval)
return get_pixel2d(image, rows, cols, <int>round(r), <int>round(c),
mode, cval)
cdef inline double bilinear_interpolation(double* image, int rows, int cols,
@@ -72,10 +72,10 @@ cdef inline double bilinear_interpolation(double* image, int rows, int cols,
maxc = <int>ceil(c)
dr = r - minr
dc = c - minc
top = (1 - dc) * get_pixel(image, rows, cols, minr, minc, mode, cval) \
+ dc * get_pixel(image, rows, cols, minr, maxc, mode, cval)
bottom = (1 - dc) * get_pixel(image, rows, cols, maxr, minc, mode, cval) \
+ dc * get_pixel(image, rows, cols, maxr, maxc, mode, cval)
top = (1 - dc) * get_pixel2d(image, rows, cols, minr, minc, mode, cval) \
+ dc * get_pixel2d(image, rows, cols, minr, maxc, mode, cval)
bottom = (1 - dc) * get_pixel2d(image, rows, cols, maxr, minc, mode, cval) \
+ dc * get_pixel2d(image, rows, cols, maxr, maxc, mode, cval)
return (1 - dr) * top + dr * bottom
@@ -144,7 +144,7 @@ cdef inline double biquadratic_interpolation(double* image, int rows, int cols,
# row-wise cubic interpolation
for pr in range(r0, r0 + 3):
for pc in range(c0, c0 + 3):
fc[pc - c0] = get_pixel(image, rows, cols, pr, pc, mode, cval)
fc[pc - c0] = get_pixel2d(image, rows, cols, pr, pc, mode, cval)
fr[pr - r0] = quadratic_interpolation(xc, fc)
# cubic interpolation for interpolated values of each row
@@ -216,15 +216,15 @@ cdef inline double bicubic_interpolation(double* image, int rows, int cols,
# row-wise cubic interpolation
for pr in range(r0, r0 + 4):
for pc in range(c0, c0 + 4):
fc[pc - c0] = get_pixel(image, rows, cols, pr, pc, mode, cval)
fc[pc - c0] = get_pixel2d(image, rows, cols, pr, pc, mode, cval)
fr[pr - r0] = cubic_interpolation(xc, fc)
# cubic interpolation for interpolated values of each row
return cubic_interpolation(xr, fr)
cdef inline double get_pixel(double* image, int rows, int cols, int r, int c,
char mode, double cval):
cdef inline double get_pixel2d(double* image, int rows, int cols, int r, int c,
char mode, double cval):
"""Get a pixel from the image, taking wrapping mode into consideration.
Parameters
@@ -255,6 +255,40 @@ cdef inline double get_pixel(double* image, int rows, int cols, int r, int c,
return image[coord_map(rows, r, mode) * cols + coord_map(cols, c, mode)]
cdef inline double get_pixel3d(double* image, int rows, int cols, int dims, int r,
int c, int d, char mode, double cval):
"""Get a pixel from the image, taking wrapping mode into consideration.
Parameters
----------
image : double array
Input image.
rows, cols, dims : int
Shape of image.
r, c, d : int
Position at which to get the pixel.
mode : {'C', 'W', 'R', 'N'}
Wrapping mode. Constant, Wrap, Reflect or Nearest.
cval : double
Constant value to use for constant mode.
Returns
-------
value : double
Pixel value at given position.
"""
if mode == 'C':
if (r < 0) or (r > rows - 1) or (c < 0) or (c > cols - 1):
return cval
else:
return image[r * cols * dims + c * dims + d]
else:
return image[coord_map(rows, r, mode) * cols * dims
+ coord_map(cols, c, mode) * dims
+ d]
cdef inline int coord_map(int dim, int coord, char mode):
"""
Wrap a coordinate, according to a given mode.