我希望可以阈值为3种颜色：黑色、白色和灰色，而不仅仅是黑色和白色，这样以后我就可以把贴纸从原来的img中分离出来

现在我的.py脚本可以阈值化，使图像的颜色为白色色

import numpy as np
import glob
import matplotlib.pyplot as plt
import skimage.io
import skimage.color
import skimage.filters


# load the image
image = skimage.io.imread("/home/student_joy/desktop/optimization_11_10/original_duplicate.png")[:,:,:3]

# image = imageio.imread(image_name)[:,:,:3]
# img = rgb2gray(image)

fig, ax = plt.subplots()
plt.imshow(image)

# convert the image to grayscale
gray_image = skimage.color.rgb2gray(image)

# blur the image to denoise
blurred_image = skimage.filters.gaussian(gray_image, sigma=1.0)

fig, ax = plt.subplots()
plt.imshow(blurred_image, cmap="gray")

# create a histogram of the blurred grayscale image
histogram, bin_edges = np.histogram(blurred_image, bins=256, range=(0.0, 1.0))

fig, ax = plt.subplots()
plt.plot(bin_edges[0:-1], histogram)
plt.title("Grayscale Histogram")
plt.xlabel("grayscale value")
plt.ylabel("pixels")
plt.xlim(0, 1.0)

# create a mask based on the threshold
t = 0.72
binary_mask = blurred_image < t

fig, ax = plt.subplots()
plt.imshow(binary_mask, cmap="gray")

plt.show()

见结果图：https://imgur.com/a/u4KvF7Z
我不确定如何正确设置binary_mask，即t值