用点重新缩放零矩阵

Question

我有一个矩阵

import numpy as np
matrix =np.zeros((5,5))
matrix[(3,3)] = 1

我想将它缩放到例如50x50的大小，因为我需要将它保存到图像

from PIL import Image
img = Image.fromarray(matrix,'RGB').save('my.png')

我该如何扩展它？

Answer 1

我该如何扩展它？

如果所需尺寸除以实际尺寸，您可以使用Kronecker 产品。 例如，假设您想将 5x5 放大到 15x15 尺寸，我们发现 15/5 给出3所以我们将使用np.ones((3,3)) ：

import numpy as np
matrix =np.zeros((5,5))
matrix[(3,3)] = 1
result = np.kron(matrix, np.ones((3,3)))
print(matrix)
print(result)

output 用于矩阵

[[0. 0. 0. 0. 0.]
 [0. 0. 0. 0. 0.]
 [0. 0. 0. 0. 0.]
 [0. 0. 0. 1. 0.]
 [0. 0. 0. 0. 0.]]

output 结果

[[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. 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. 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. 1. 1. 1. 0. 0. 0.]
 [0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 1. 1. 0. 0. 0.]
 [0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 1. 1. 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.]]

如果您想使用更高级的缩放算法，我建议使用 OpenCV 的cv2.resize function ，它可以将图像处理为numpy.array 。