“TypeError: only integer scalar arrays can be converted to a scalar index” when comparing a float with the value from an array

Question

当我尝试运行以下非最大抑制函数时，在将 -22.5 与 Gmat[i,j] 进行比较的行出现错误：

我使用 np.all 和 np.any 因为 and 和 or 会给出一个名为 'ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()'

的错误

def non_max_suppression(Gmag, Gmat):
   nms_img = np.zeros(Gmag.shape)
   for i in range (1, int(Gmag.shape[0])-1):
       for j in range (1, int(Gmag.shape[1])-1):
           if np.any(
                   np.all(
                       Gmat[i,j] >=
                       -22.5 ,
                       Gmat[i,j] <=
                       22.5) , #doesnt go past here, this is where the error occurs
                   np.all(Gmat[i,j] <= -157.5, Gmat[i,j] >= 157.5)
           ):
               if np.logical_and(Gmag[i,j] > Gmag[i,j+1] , Gmag[i,j] > Gmag[i,j-1]):
                   nms_img[i,j] = Gmag[i,j]
               else:
                   nms_img[i,j] = 0

           if np.logical_or(
                   np.logical_and(Gmat[i,j] >= 22.5 , Gmat[i,j] <= 67.5) ,
                   np.logical_and(Gmat[i,j] <= -112.5 , Gmat[i,j] >= -157.5)
           ):
               if np.logical_and(Gmag[i,j] > Gmag[i+1,j] , Gmag[i,j] > Gmag[i-1,j-1]):
                   nms_img[i,j] = Gmag[i,j]
               else:
                   nms_img[i,j] = 0

           if np.logical_or(
                   np.logical_and(Gmat[i,j] >= 67.5 , Gmat[i,j] <= 112.5) ,
                   np.logical_and(Gmat[i,j] <= -67.5 , Gmat[i,j] >= -112.5)
           ):
               if np.logical_and(Gmag[i,j] > Gmag[i+1,j] , Gmag[i,j] > Gmag[i-1,j]):
                   nms_img[i,j] = Gmag[i,j]
               else:
                   nms_img[i,j] = 0

           if np.logical_or(
                   np.logical_and(Gmat[i,j] >= 112.5 , Gmat[i,j] <= 157.5) ,
                   np.logical_and(Gmat[i,j] <= -22.5 , Gmat[i,j] >= -67.5)
           ):
               if np.logical_and(Gmag[i,j] > Gmag[i,j+1] , Gmag[i,j] > Gmag[i-1,j+1]):
                   nms_img[i,j] = Gmag[i,j]
               else:
                   nms_img[i,j] = 0
   return nms_img

Gmag 和 Gmat 的值分别如下：

 Mag = {ndarray: (262, 393, 3)} [[[0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.],  ...,  [0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.]],, [[0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.],  ...,  [0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.]],, [[0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.],  ...,  [0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.]]
 min = {float64} 0.0
 max = {float64} 1.7116336200484585
 shape = {tuple: 3} (262, 393, 3)
 dtype = {dtype: 0} float64
 size = {int} 308898
 array = {NdArrayItemsContainer} <pydevd_plugins.extensions.types.pydevd_plugin_numpy_types.NdArrayItemsContainer object at 0x00000275D41FAC08>

 Gmat = {ndarray: (262, 393, 3)} [[[0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.],  ...,  [0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.]],, [[0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.],  ...,  [0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.]],, [[0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.],  ...,  [0. 0. 0.],  [0. 0. 0.],  [0. 0. 0.]]
 min = {float64} -135.0
 max = {float64} 45.0
 shape = {tuple: 3} (262, 393, 3)
 dtype = {dtype: 0} float64
 size = {int} 308898
 array = {NdArrayItemsContainer} <pydevd_plugins.extensions.types.pydevd_plugin_numpy_types.NdArrayItemsContainer object at 0x00000275D46BE048>

完整错误：

TypeError                                 Traceback (most recent call last)

<ipython-input-104-991cd7244b0e> in <module>
      1 #============================ 10 Apply Non-Maximum Suppression
----> 2 img_NMS = non_max_suppression(Mag, Gmat)
      3 img_NMS = normalize(img_NMS)
      4 
      5 plt.imshow(img_NMS, cmap = plt.get_cmap('gray'))

<ipython-input-103-2ec719b48bd0> in non_max_suppression(Gmag, Gmat)
      9                         -22.5 ,
     10                         Gmat[i,j] <=
---> 11                         22.5) ,
     12                     np.all(Gmat[i,j] <= -157.5, Gmat[i,j] >= 157.5)
     13             ):

<__array_function__ internals> in all(*args, **kwargs)

c:\users\user\appdata\local\programs\python\python37\lib\site-packages\numpy\core\fromnumeric.py in all(a, axis, out, keepdims)
   2409 
   2410     
-> 2411     return _wrapreduction(a, np.logical_and, 'all', axis, None, out, keepdims=keepdims)
   2412 
   2413 

c:\users\user\appdata\local\programs\python\python37\lib\site-packages\numpy\core\fromnumeric.py in _wrapreduction(obj, ufunc, method, axis, dtype, out, **kwargs)
     85                 return reduction(axis=axis, out=out, **passkwargs)
     86 
---> 87     return ufunc.reduce(obj, axis, dtype, out, **passkwargs)
     88 
     89 

TypeError: only integer scalar arrays can be converted to a scalar index

Answer 1

Gmag 本来应该是二维数组，却变成了三维数组。

将 Gmag 转换为二维数组并使用 numpy.logical_and 和 numpy.logical_or 而不是 numpy.any 和 numpy.all 解决了问题。

“TypeError: only integer scalar arrays can be converted to a scalar index” when comparing a float with the value from an array

“TypeError: only integer scalar arrays can be converted to a scalar index” when comparing a float with the value from an array

python

arrays

image-processing

canny-operator

non-maximum-suppression