图像重建（侵蚀和膨胀）均提供黑色图像作为输出

I am trying to remove the black spots from a face of this image using the erosion methods.

我已经实现了：

img = skimage.io.imread('blemish.jpeg')
img = skimage.color.rgb2gray(img)
img_inten = skimage.exposure.rescale_intensity(img,in_range=(50,100))

diliation_seed = img_inten.copy()
diliation_seed[1:-1,1:-1] = img_inten.min()
mask = img_inten

eroded_img = skimage.morphology.reconstruction(diliation_seed,mask,method='dilation')
matplotlib.pyplot.imshow(eroded_img,cmap='gray')

在两种情况下，我的输出始终都是黑色图像。这是怎么了？