python - 去掉边缘的黑线

Question

我有一个检测地板的程序，所以我检测到的地板被移除并变成透明的png，但边缘仍然有黑线

before adding threshold

enter image description here

enter image description here

src = cv2.imread(file_name)
    
tmp = cv2.cvtColor(src, cv2.COLOR_BGR2GRAY)
_,alpha = cv2.threshold(tmp,0, 255, cv2.THRESH_BINARY)
 b, g, r = cv2.split(src)
 rgba = [b,g,r, alpha]
 dst = cv2.merge(rgba,1)
    

Answer 1

您可以通过对 alpha channel 进行抗锯齿来减轻 Python/OpenCV/Skimage 中黑色过渡线的影响，如下所示:

• 使用 alpha 读取图像
• 提取 bgr 基础图像
• 提取 alpha channel
• 高斯模糊 alpha channel (选择模糊量以匹配黑色过渡)
• 拉伸(stretch) alpha channel 的动态范围，使 255 -> 255 和中灰变为 0 并保存为 mask 。 (选择中灰度级进一步减轻)
• 将生成的mask图像放入bgr图像的alpha channel
• 保存结果

输入:

import cv2
import numpy as np
import skimage.exposure

# load image with alpha
img = cv2.imread('room.png', cv2.IMREAD_UNCHANGED)

# extract only bgr channels
bgr = img[:, :, 0:3]

# extract alpha channel
alpha = img[:, :, 3]

# apply Gaussian blur to alpha
blur = cv2.GaussianBlur(alpha, (0,0), sigmaX=5, sigmaY=5, borderType = cv2.BORDER_DEFAULT)

# stretch so that 255 -> 255 and 192 -> 0
mask = skimage.exposure.rescale_intensity(blur, in_range=(192,255), out_range=(0,255)).astype(np.uint8)

# put mask into alpha channel
result = np.dstack((bgr, mask))

# save result
cv2.imwrite('room_new_alpha.png', result)

# display result, though it won't show transparency
cv2.imshow("bgr", bgr)
cv2.imshow("alpha", alpha)
cv2.imshow("mask", mask)
cv2.imshow("result", result)
cv2.waitKey(0)
cv2.destroyAllWindows()

结果: