python - 如何让 grabCut 与 GC_INIT_WITH_MASK 一起工作 opencv python

Question

我正在尝试让 messi 示例起作用:https://docs.opencv.org/3.1.0/d8/d83/tutorial_py_grabcut.html

在我的设置中，我希望整个过程自动化。

例如，我从网上抓取一张图片: http://wanderlustandlipstick.com/travel-tips/opting-out-full-body-scanners/

并使用一些 opencv 工具自动生成以下掩码:

黑色应该是某个背景，白色应该是某个前景，灰色应该是未知。

按照梅西教程(https://docs.opencv.org/3.1.0/d8/d83/tutorial_py_grabcut.html)，下面是我的代码。但是，它只显示了白色的小圆圈区域，就像把灰色当成黑色一样(某背景)

import numpy as np
import cv2
from matplotlib import pyplot as plt

img = cv2.imread("imagescan.png")
dimy = np.shape(img)[0] # seems to be backwards (x,y)
# https://stackoverflow.com/questions/22490721/how-can-i-get-the-x-and-y-dimensions-of-a-ndarray-numpy-python
dimx = np.shape(img)[1]
mask = np.zeros((dimy,dimx),np.uint8) # zeroes as array/matrix size of image
bgdModel = fgdModel = np.zeros((1,65),np.float64)    

newmask = cv2.imread('imagemask.png',0)

# informational purposes
removeBg = (newmask == 0)
removeBg = np.ravel(removeBg)
np.bincount(removeBg)
keepFg = (newmask == 255)
keepFg = np.ravel(keepFg)
np.bincount(keepFg)

#otherEl = (not (newmask == 0 or newmask == 255)) # throws error
#otherEl = np.ravel(otherEl)
#np.bincount(otherEl)

# appears at least one of each elements is required
# otherwise throws bgdSamples.empty error / fgdSamples.empty error
mask[newmask == 0] = 0
mask[newmask == 255] = 1

mask, bgdModel, fgdModel = cv2.grabCut(img,mask,None,bgdModel,fgdModel,5,cv2.GC_INIT_WITH_MASK)

mask2 = np.where((mask==2)|(mask==0),0,1).astype('uint8')
img2 = img*mask2[:,:,np.newaxis]
plt.imshow(img2),plt.colorbar(),plt.show()

结果只是圆圈外的蒙版，就好像灰色区域被视为黑色一样。

Answer 1

在蒙版图像中，基本上有 3 种颜色:黑色、白色、灰色。在下面的代码行中，您将设置背景和前景，但不是可能的前景。

mask[newmask == 0] = 0
mask[newmask == 255] = 1

尝试使用 OpenCV 提供的常量(cv2.GC_BGD 等)以避免混淆。

# this line sets the grey areas - meaning any color not 0 and not 255 - to probable foreground.
mask = np.where(((newmask>0) & (newmask<255)),cv2.GC_PR_FGD,0).astype('uint8')
mask[newmask == 0] = cv2.GC_BGD
mask[newmask == 255] = cv2.GC_FGD

.