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Merge pull request #536 from ahojnnes/edge-weights

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Some tweaks for edges.py
This commit is contained in:
Tony S Yu
2013-05-06 08:17:00 -07:00
parent c8bd937d00 cec8516f69
commit 4d7905951b
1 changed files with 41 additions and 43 deletions
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skimage/filter/edges.py
+41 -43
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@@ -1,4 +1,4 @@
"""edges.py - Edge filters
"""
Sobel and Prewitt filters originally part of CellProfiler, code licensed under
both GPL and BSD licenses.
@@ -16,6 +16,26 @@ from scipy.ndimage import convolve, binary_erosion, generate_binary_structure
EROSION_SELEM = generate_binary_structure(2, 2)
HSOBEL_WEIGHTS = np.array([[ 1, 2, 1],
[ 0, 0, 0],
[-1,-2,-1]]) / 4.0
VSOBEL_WEIGHTS = HSOBEL_WEIGHTS.T
HSCHARR_WEIGHTS = np.array([[ 3, 10, 3],
[ 0, 0, 0],
[-3, -10, -3]]) / 16.0
VSCHARR_WEIGHTS = HSCHARR_WEIGHTS.T
HPREWITT_WEIGHTS = np.array([[ 1, 1, 1],
[ 0, 0, 0],
[-1,-1,-1]]) / 3.0
VPREWITT_WEIGHTS = HPREWITT_WEIGHTS.T
ROBERTS_PD_WEIGHTS = np.array([[ 1, 0],
[ 0, -1]], dtype=np.double)
ROBERTS_ND_WEIGHTS = np.array([[0, 1],
[-1, 0]], dtype=np.double)
def _mask_filter_result(result, mask):
"""Return result after masking.
@@ -48,7 +68,7 @@ def sobel(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Sobel edge map.
Notes
@@ -77,7 +97,7 @@ def hsobel(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Sobel edge map.
Notes
@@ -91,10 +111,7 @@ def hsobel(image, mask=None):
"""
image = img_as_float(image)
result = np.abs(convolve(image,
np.array([[ 1, 2, 1],
[ 0, 0, 0],
[-1,-2,-1]]).astype(float) / 4.0))
result = np.abs(convolve(image, HSOBEL_WEIGHTS))
return _mask_filter_result(result, mask)
@@ -112,7 +129,7 @@ def vsobel(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Sobel edge map.
Notes
@@ -126,10 +143,7 @@ def vsobel(image, mask=None):
"""
image = img_as_float(image)
result = np.abs(convolve(image,
np.array([[1, 0, -1],
[2, 0, -2],
[1, 0, -1]]).astype(float) / 4.0))
result = np.abs(convolve(image, VSOBEL_WEIGHTS))
return _mask_filter_result(result, mask)
@@ -147,7 +161,7 @@ def scharr(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Scharr edge map.
Notes
@@ -179,7 +193,7 @@ def hscharr(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Scharr edge map.
Notes
@@ -198,10 +212,7 @@ def hscharr(image, mask=None):
"""
image = img_as_float(image)
result = np.abs(convolve(image,
np.array([[ 3, 10, 3],
[ 0, 0, 0],
[-3, -10, -3]]).astype(float) / 16.0))
result = np.abs(convolve(image, HSCHARR_WEIGHTS))
return _mask_filter_result(result, mask)
@@ -219,7 +230,7 @@ def vscharr(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Scharr edge map.
Notes
@@ -238,10 +249,7 @@ def vscharr(image, mask=None):
"""
image = img_as_float(image)
result = np.abs(convolve(image,
np.array([[ 3, 0, -3],
[10, 0, -10],
[ 3, 0, -3]]).astype(float) / 16.0))
result = np.abs(convolve(image, VSCHARR_WEIGHTS))
return _mask_filter_result(result, mask)
@@ -259,7 +267,7 @@ def prewitt(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Prewitt edge map.
Notes
@@ -284,7 +292,7 @@ def hprewitt(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Prewitt edge map.
Notes
@@ -298,10 +306,7 @@ def hprewitt(image, mask=None):
"""
image = img_as_float(image)
result = np.abs(convolve(image,
np.array([[ 1, 1, 1],
[ 0, 0, 0],
[-1,-1,-1]]).astype(float) / 3.0))
result = np.abs(convolve(image, HPREWITT_WEIGHTS))
return _mask_filter_result(result, mask)
@@ -319,7 +324,7 @@ def vprewitt(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Prewitt edge map.
Notes
@@ -333,10 +338,7 @@ def vprewitt(image, mask=None):
"""
image = img_as_float(image)
result = np.abs(convolve(image,
np.array([[1, 0, -1],
[1, 0, -1],
[1, 0, -1]]).astype(float) / 3.0))
result = np.abs(convolve(image, VPREWITT_WEIGHTS))
return _mask_filter_result(result, mask)
@@ -354,7 +356,7 @@ def roberts(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Roberts' Cross edge map.
"""
return np.sqrt(roberts_positive_diagonal(image, mask)**2 +
@@ -378,7 +380,7 @@ def roberts_positive_diagonal(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Robert's edge map.
Notes
@@ -391,9 +393,7 @@ def roberts_positive_diagonal(image, mask=None):
"""
image = img_as_float(image)
result = np.abs(convolve(image,
np.array([[ 1, 0],
[ 0, -1]]).astype(float)))
result = np.abs(convolve(image, ROBERTS_PD_WEIGHTS))
return _mask_filter_result(result, mask)
@@ -414,7 +414,7 @@ def roberts_negative_diagonal(image, mask=None):
Returns
-------
output : ndarray
output : 2-D array
The Robert's edge map.
Notes
@@ -427,7 +427,5 @@ def roberts_negative_diagonal(image, mask=None):
"""
image = img_as_float(image)
result = np.abs(convolve(image,
np.array([[0, 1],
[-1, 0]]).astype(float)))
result = np.abs(convolve(image, ROBERTS_ND_WEIGHTS))
return _mask_filter_result(result, mask)