裁剪 numpy.ndArray 报错 - ValueError: 不能将空图像保存为 JPEG

Question

我正在尝试把一个numpy数组的图像裁剪成更小的块，并保存它们。但是当我试图保存这些小块时，出现了一个错误，提示图像是空的。

我的脚本考虑到了那些没有达到块大小的多余像素，并把它们分散到边缘。

print("Slicing Image.")

path = 'Sliced/'
filename= 'sample_svs_2_'
img = tif.imread('sample_svs_2.svs')
print(type(img)) 
print(img.shape) 

#This works, proving that 
#this method of saving is valid
data = im.fromarray(img)
data.save('Sliced/sample.jpg') 


#depth, height, width  = img.shape
height, width, depth = img.shape
tilesize = 256

print("Height: ", height)
print("Width: ", width)
print("Depth: ", depth)

leftExcessPixels = int((width%tilesize)/2)
topExcessPixels = int((height%tilesize)/2)
XNumberOfTiles = int(width/tilesize)
YNumberOfTiles = int(height/tilesize)

print('Left Excess Pixels: ' + str(leftExcessPixels) )
print('Top Excess Pixels: ' + str(topExcessPixels) )

print('Number of X tiles: ' + str(XNumberOfTiles))
print('Number of Y tiles: ' + str(YNumberOfTiles))

for y in range(YNumberOfTiles):
    for x in range(XNumberOfTiles):
        XStart = (leftExcessPixels + (tilesize * x))
        YStart = (topExcessPixels + (tilesize * y))
        XEnd = XStart + tilesize
        YEnd = YStart + tilesize
        croppedImage = img[XStart:YStart, XEnd:YEnd] 
        data = im.fromarray(croppedImage)
        data.save('Sliced/sample_x' + str(x) + '_y' + str(y) + '.jpg')

终端输出：

Slicing Image.
<class 'numpy.ndarray'>
(13271, 19992, 3)
Height:  13271
Width:  19992
Depth:  3
Left Excess Pixels: 12
Top Excess Pixels: 107
Number of X tiles: 78
Number of Y tiles: 51
Traceback (most recent call last):
  File "c:\fileImageSlicer.py", line 72, in <module>
    sliceImage()
  File "c:\fileImageSlicer.py", line 52, in sliceImage
    data.save('Sliced/sample_x' + str(x) + '_y' + str(y) + '.jpg')
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\miniconda3\Lib\site-packages\PIL\Image.py", line 2439, in save
    save_handler(self, fp, filename)
  File "C:\miniconda3\Lib\site-packages\PIL\JpegImagePlugin.py", line 647, in _save
    raise ValueError(msg)
ValueError: cannot write empty image as JPEG

我可能哪里做错了呢？有一点我完全忽视了，就是读取的图像有一个z维度（深度？）。我不太明白为什么图像会有深度（可能是为了颜色？RGB），而我也不太确定该怎么使用它……

错误处理 numpy 图像处理数组裁剪 z维度 RGB颜色图像保存

裁剪 numpy.ndArray 报错 - ValueError: 不能将空图像保存为 JPEG

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