如何将我的二进制 numpy 数组列表转换为图像？答案

【问题标题】：How can i transform my binary numpy list of arrays to an image?如何将我的二进制 numpy 数组列表转换为图像？
【发布时间】：2018-06-19 14:26:46
【问题描述】：

[[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 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 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 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 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 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 1 1 0 0 3 3 0 0 0 4 4 0 0 0 5 5 5 5 0 0 2 2 2 2 2 0 2 2 2 2 2 0 0 0 6 6 6 6 6 6 0 6 6 6 6]
 [0 1 1 0 0 0 0 0 0 0 0 0 0 3 3 0 0 0 4 4 0 0 5 5 5 5 5 5 0 2 2 2 2 2 2 2 2 2 2 2 2 0 0 6 6 6 6 6 6 6 6 6 6 6]
 [1 1 1 0 0 0 0 0 0 0 0 0 0 3 3 0 0 0 4 4 0 5 5 5 0 0 5 5 5 0 2 2 0 0 2 2 0 0 0 2 2 0 0 6 6 0 0 6 6 6 0 0 6 6]
 [1 1 1 0 0 0 0 0 0 0 0 0 0 3 3 0 0 0 4 4 0 5 5 5 5 0 0 0 0 0 2 2 0 2 2 2 0 0 0 2 2 2 0 6 6 0 0 0 6 6 0 0 6 6]
 [1 1 1 0 0 0 0 0 0 0 0 0 0 3 3 0 0 0 4 4 0 0 5 5 5 5 5 5 0 0 2 2 0 2 2 2 0 0 0 2 2 2 0 6 6 0 0 0 6 6 0 0 6 6]
 [0 1 1 0 0 0 0 0 0 7 0 0 0 3 3 0 0 0 4 4 0 0 0 0 5 5 5 5 5 0 2 2 0 2 2 2 0 0 0 2 2 2 0 6 6 0 0 0 6 6 0 0 6 6]]

作为第一步，我希望不同于 0 的像素为白色，而 0 像素为黑色。我做了什么将无 0 值全部转换为 1：

binary_transform = np.array(labels).astype(bool).astype(int)

它起作用了，然后我想将 1 和 0 的数组列表转换为图像，我尝试了什么：

from PIL import Image

img = Image.fromarray(binary_transform, '1')
img.save('image.png')

Image.fromarray 的文档可以在这里找到https://pillow.readthedocs.io/en/3.1.x/reference/Image.html

它没有工作，然后我尝试了以下方法：

import png

png.from_array(binary_transform, 'L').save('image.png')

参考文档'L' 是灰度，而我想要二进制但我没有看到二进制选项，文档https://pythonhosted.org/pypng/png.html

我收到了这个错误ValueError: bitdepth (64) must be a positive integer <= 16

【问题讨论】：

标签： python arrays image numpy image-processing

【解决方案1】：

虽然你没有明确地这么说，但你说“作为第一步......”的事实让我觉得你正朝着灰度调色板图像前进：

import numpy as np
from PIL import Image
labels=[[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],
 [0,0,0,0,0,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
 [0,0,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
 [0,0,1,1,1,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
 [0,1,1,1,0,0,0,0,0,1,1,0,0,3,3,0,0,0,4,4,0,0,0,5,5,5,5,0,0,2,2,2,2,2,0,2,2,2,2,2,0,0,0,6,6,6,6,6,6,0,6,6,6,6],
 [0,1,1,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,4,4,0,0,5,5,5,5,5,5,0,2,2,2,2,2,2,2,2,2,2,2,2,0,0,6,6,6,6,6,6,6,6,6,6,6],
 [1,1,1,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,4,4,0,5,5,5,0,0,5,5,5,0,2,2,0,0,2,2,0,0,0,2,2,0,0,6,6,0,0,6,6,6,0,0,6,6],
 [1,1,1,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,4,4,0,5,5,5,5,0,0,0,0,0,2,2,0,2,2,2,0,0,0,2,2,2,0,6,6,0,0,0,6,6,0,0,6,6],
 [1,1,1,0,0,0,0,0,0,0,0,0,0,3,3,0,0,0,4,4,0,0,5,5,5,5,5,5,0,0,2,2,0,2,2,2,0,0,0,2,2,2,0,6,6,0,0,0,6,6,0,0,6,6],
 [0,1,1,0,0,0,0,0,0,7,0,0,0,3,3,0,0,0,4,4,0,0,0,0,5,5,5,5,5,0,2,2,0,2,2,2,0,0,0,2,2,2,0,6,6,0,0,0,6,6,0,0,6,6]]
binary_transform = np.array(labels).astype(np.uint8)
img = Image.fromarray(binary_transform, 'P')
img.save('image.png')

请注意，出于显示目的，我已经调整了图像的大小并进行了对比度拉伸。

如果您真的只想要一个真正的二进制黑白图像，请使用：

binary_transform = np.array(labels).astype(np.uint8)
binary_transform[binary_transform>0] = 255
img = Image.fromarray(binary_transform, 'L')
img.save('image.png')

【讨论】：

其实不是灰度图，是连通分量函数的输出应用于灰度图(cv2.connectedComponents)
我猜是 Connected Components 标签 :-)

【解决方案2】：

如果我理解正确，您希望图像显示为二进制，即只有黑色和白色，没有灰色。如果是这样的话，OpenCV 就是你的朋友：

import cv2
import numpy as np

binary_transform = np.array(labels).astype(np.uint8)

_,thresh_img = cv2.threshold(binary_transform, 0, 255, cv2.THRESH_BINARY)

cv2.imwrite('image.png', thresh_img)

当然 PIL 也可以，您只需要调整非零值即可。

binary_transform = np.array(labels).astype(np.uint8)
binary_transform[binary_transform > 0] = 255

img = Image.fromarray(binary_transform, 'L')
img.save('image.png')

【讨论】：

很酷，并且 +1 以两种不同的方式进行！

【解决方案3】：

其他答案（都很好！）使用 OpenCV 或 PIL。以下是使用 numpngw 创建图像的方法，这是我编写的一个小型库，用于从 numpy 数组创建 PNG 文件。

首先，这是我的示例数据：

In [173]: x
Out[173]: 
[[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, 1, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 1, 1, 1, 1, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 1, 1, 1, 1, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
 [0, 1, 1, 1, 1, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 2, 2, 2, 2, 2, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 2, 2, 2, 2, 2, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 2, 2, 2, 2, 2, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 2, 2, 2, 2, 2, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 2, 2, 2, 2, 2, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 2, 2, 2, 2, 2, 0],
 [0, 0, 0, 0, 0, 0, 3, 0, 0, 0, 0, 0, 4, 4, 4, 4, 4, 0, 2, 2, 2, 2, 2, 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]]

使用numpngw.write_png()创建图像：

In [174]: import numpy as np

In [175]: import numpngw

In [176]: numpngw.write_png("foo.png", (np.array(x) > 0).astype(np.uint8), bitdepth=1)

这是图片：

【讨论】：