我有一个使用scipy.ndimage标记过的数组,我希望将每个元素乘以特定于其相应标签的因子。我认为我可以使用ndimage.labeled_comprehension,但是我似乎无法弄清楚如何将参数传递给函数。例如:
"word word, word, word,".gsub(',', ', ').squeeze(' ')
#=> "word word, word, word, "
正如预期的那样,它会出现错误,因为a = np.random.random(9).reshape(3,3)
lbls = np.repeat(np.arange(3),3).reshape(3,3)
ndx = np.arange(0,lbls.max()+1)
factors = np.random.randint(10,size=3)
>>> lbls
array([[0, 0, 0],
[1, 1, 1],
[2, 2, 2]])
>>> ndx
array([0, 1, 2])
>>> factors
array([5, 4, 8])
def fn(a, x):
return a*x
>>> b = ndimage.labeled_comprehension(a, labels=lbls, index=ndx, func=fn, out_dtype=float, default=0)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/tgrant/anaconda/envs/python2/lib/python2.7/site-packages/scipy/ndimage/measurements.py", line 416, in labeled_comprehension
do_map([input], temp)
File "/Users/tgrant/anaconda/envs/python2/lib/python2.7/site-packages/scipy/ndimage/measurements.py", line 411, in do_map
output[i] = func(*[inp[l:h] for inp in inputs])
TypeError: fn() takes exactly 2 arguments (1 given)
需要fn()
以某种方式输入它。 labeled_comprehension能够做到吗?
答案 0 :(得分:1)
索引因子,然后简单地与图像数组相乘 -
a*factors[lbls]
示例运行 -
In [483]: a # image/data array
Out[483]:
array([[ 0.10682998, 0.29631501, 0.08501469],
[ 0.46944505, 0.88346229, 0.75672908],
[ 0.11381292, 0.24096868, 0.86438641]])
In [484]: factors # scaling factors
Out[484]: array([8, 1, 1])
In [485]: lbls # labels
Out[485]:
array([[0, 0, 0],
[1, 1, 1],
[2, 2, 2]])
In [486]: factors[lbls] # factors populated based on the labels
Out[486]:
array([[8, 8, 8],
[1, 1, 1],
[1, 1, 1]])
In [487]: a*factors[lbls] # finally scale the image array
Out[487]:
array([[ 0.85463981, 2.37052006, 0.68011752],
[ 0.46944505, 0.88346229, 0.75672908],
[ 0.11381292, 0.24096868, 0.86438641]])