python - 使用 Python/PIL 从图像中删除背景颜色

Question

我一直在努力让它工作，但我真的遇到了麻烦，所以非常感谢您的帮助。

使用下面的代码，我想将具有指定 RGB 值的特征更改为白色，并将图像中的所有其他特征更改为黑色(即基本上从图像中提取特征。不幸的是，虽然我可以使特征我当我尝试删除背景颜色时(我一直在尝试使用

mask2 = ((red != r1) & (green != g1) & (blue != b1))
data[:,:,:4][mask2] = [rb, gb, bb, ab]

但这似乎选择了除 red == r1 或 green == g1 等像素之外的任何像素，给我留下了一个非常“嘈杂”的背景图像。)有谁知道一种方法来从字面上提取这些像素指定的 RGB 值，或重新着色背景像素的更好方法？

谢谢

import numpy as np
from PIL import Image

im = Image.open('/home/me/nh09sw.tif')
im = im.convert('RGBA')
data = np.array(im)

r1, g1, b1 = 246, 213, 139 # Original value
rw, gw, bw, aw = 255, 255, 255, 255 # Value that we want to replace features with
rb, gb, bb, ab = 0, 0, 0, 255 #value we want to use as background colour

red, green, blue, alpha = data[:,:,0], data[:,:,1], data[:,:,2], data[:,:,3]

mask = ((red == r1) & (green == g1) & (blue == b1))
data[:,:,:4][mask] = [rw, gw, bw, aw]

im = Image.fromarray(data)

im.save('/home/me/nh09sw_recol.tif')

Answer 1

使用 np.all() 沿第三个轴进行比较。

import numpy as np
from PIL import Image

im = Image.open('my_file.tif')
im = im.convert('RGBA')
data = np.array(im)
# just use the rgb values for comparison
rgb = data[:,:,:3]
color = [246, 213, 139]   # Original value
black = [0,0,0, 255]
white = [255,255,255,255]
mask = np.all(rgb == color, axis = -1)
# change all pixels that match color to white
data[mask] = white

# change all pixels that don't match color to black
##data[np.logical_not(mask)] = black
new_im = Image.fromarray(data)
new_im.save('new_file.tif')