将Numpy数组保存为图像（说明）

Question

我在之前的帖子中找到了我的答案：将Numpy数组保存为图像。唯一的问题是，关于如何使用PyPNG模块的说明不多。

网上只有几个例子—— http://packages.python.org/pypng/ex.html#numpy http://nullege.com/codes/search/png.Writer.write

但是我该怎么处理像这样的.write错误呢：

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/png.py", line 638, in write
    nrows = self.write_passes(outfile, rows)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/png.py", line 783, in write_passes
    extend(row)
  File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/png.py", line 780, in <lambda>
    return lambda sl: f(map(int, sl))
TypeError: argument 2 to map() must support iteration

这是我代码中的错误发生位置，PCA_tool.py（错误发生在“folder.write(outfilename, PrincipalComponent”之后）：

#PrincipalComponent.save(path+'transform_'+str(each)+'.png', format='PNG')
outfilename = open(str(path)+'transformed/transform_'+str(each)+'.png', 'wb')
folder = png.Writer(m,n,greyscale=True)
folder.write(outfilename, PrincipalComponent)
outfilename.close()

sys.exit(0)

我正在尝试将一个包含8400个元素的numpy.ndarray保存为一个n=80列，m=105行的灰度png图像。

谢谢，

Answer 1

最好使用scipy来处理这个问题。

from scipy.misc import imsave
# x is the array you want to save 
imsave("image.png", x)

完整的文档可以在这里找到： https://docs.scipy.org/doc/scipy-0.14.0/reference/generated/scipy.misc.imsave.html

Answer 2

import matplotlib.pyplot as plt
import numpy as np
plt.imshow(np.random.random(100, 100))
plt.savefig('')

当然可以！请把你想要翻译的内容发给我，我会帮你用简单易懂的语言解释清楚。

Answer 3

你可能更适合使用PIL这个库：

from PIL import Image
import numpy as np

data = np.random.random((100,100))

#Rescale to 0-255 and convert to uint8
rescaled = (255.0 / data.max() * (data - data.min())).astype(np.uint8)

im = Image.fromarray(rescaled)
im.save('test.png')