Python 将 NumPy 数组转换为 PIL 图像
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Converting a NumPy array to a PIL image
提问by Karnivaurus
I want to create a PIL image from a NumPy array. Here is my attempt:
我想从 NumPy 数组创建一个 PIL 图像。这是我的尝试：
# Create a NumPy array, which has four elements. The top-left should be pure red, the top-right should be pure blue, the bottom-left should be pure green, and the bottom-right should be yellow
pixels = np.array([[[255, 0, 0], [0, 255, 0]], [[0, 0, 255], [255, 255, 0]]])
# Create a PIL image from the NumPy array
image = Image.fromarray(pixels, 'RGB')
# Print out the pixel values
print image.getpixel((0, 0))
print image.getpixel((0, 1))
print image.getpixel((1, 0))
print image.getpixel((1, 1))
# Save the image
image.save('image.png')
However, the print out gives the following:
但是，打印出来的内容如下：
(255, 0, 0)
(0, 0, 0)
(0, 0, 0)
(0, 0, 0)
And the saved image has pure red in the top-left, but all the other pixels are black. Why are these other pixels not retaining the colour I have assigned to them in the NumPy array?
保存的图像左上角为纯红色，但所有其他像素均为黑色。为什么这些其他像素没有保留我在 NumPy 数组中分配给它们的颜色？
Thanks!
谢谢！
回答by Randy
The RGBmode is expecting 8-bit values, so just casting your array should fix the problem:
该RGB模式需要 8 位值，因此只需转换数组即可解决问题：
In [25]: image = Image.fromarray(pixels.astype('uint8'), 'RGB')
...:
...: # Print out the pixel values
...: print image.getpixel((0, 0))
...: print image.getpixel((0, 1))
...: print image.getpixel((1, 0))
...: print image.getpixel((1, 1))
...:
(255, 0, 0)
(0, 0, 255)
(0, 255, 0)
(255, 255, 0)
