OpenCV python 将多边形从一个图像复制到另一个

Question

我有两个图像。我想从一个图像中抓取一个区域（多边形，而不是矩形）并将该区域复制到另一个图像上。我怎样才能做到这一点？这是我到目前为止所拥有的。

import cv2
import numpy as np

#load two images
srcfilename = 'foo.jpg'
src1 = cv2.imread(srcfilename)
srcfilename = 'bar.jpg'
src2 = cv2.imread(srcfilename)


src1_mask = np.zeros(src1.shape[:-1])
#create a polygon for region of interest
poly = np.array([ [150,150], [200,100], [350,150], [350,200], [300,220], [200,200], [190,180] ], np.int32)
cv2.fillPoly(src1_mask, [poly], 255)

在这一点上，我加载了两个图像，并且该区域有一个多边形和蒙版。现在我不知道如何使用这个掩码/多边形将 src1 的那部分复制到 src2 上。

#I can also create a mask that has the same number of channels (3)
src1_mask = np.zeros(src1.shape)
#create a polygon for region of interest
poly = np.array([ [150,150], [200,100], [350,150], [350,200], [300,220], [200,200], [190,180] ], np.int32)
cv2.fillPoly(src1_mask, [poly], (255,255,255))

最终编辑

使用按位运算，我已经能够实现我想要的。这是示例代码。

import cv2
import numpy as np
import matplotlib.pyplot as pst

#load two images
srcfilename = 'foo.jpg'
src1 = cv2.imread(srcfilename)
srcfilename = 'bar.jpg'
src2 = cv2.imread(srcfilename)

#create mask template
src1_mask = src1.copy()
src1_mask = cv2.cvtColor(src1_mask,cv2.COLOR_BGR2GRAY)
src1_mask.fill(0)

#define polygon around region
poly = np.array([ [0,0], [20,0], [65,40], [150,40], [225,5], [225,170],[120,200], [10,190] ], np.int32)

#fill polygon in mask
_ = cv2.fillPoly(src1_mask, [poly], 255)

#create region of interest
roi = src2[np.min(poly[:,1]):np.max(poly[:,1]),np.min(poly[:,0]):np.max(poly[:,0])]
mask = src1_mask[np.min(poly[:,1]):np.max(poly[:,1]),np.min(poly[:,0]):np.max(poly[:,0])]

mask_inv = cv2.bitwise_not(mask)
img1_bg = cv2.bitwise_and(roi,roi,mask = mask_inv)
src1_cut = src1[np.min(poly[:,1]):np.max(poly[:,1]),np.min(poly[:,0]):np.max(poly[:,0])]

img2_fg = cv2.bitwise_and(src1_cut,src1_cut,mask = mask)

# Put logo in ROI and modify the main image
dst = cv2.add(img1_bg,img2_fg)
src2_final = src2.copy()
src2_final[np.min(poly[:,1]):np.max(poly[:,1]),np.min(poly[:,0]):np.max(poly[:,0])] = dst

plt.imshow(cv2.cvtColor(src2_final, cv2.COLOR_BGR2RGB))

Answer 1

假设 src1 是您的图像，而 src1_mask 是您的二进制掩码：

    src1_mask=cv2.cvtColor(src1_mask,cv2.COLOR_GRAY2BGR)#change mask to a 3 channel image 
    mask_out=cv2.subtract(src1_mask,src1)
    mask_out=cv2.subtract(src1_mask,mask_out)

现在 mask_out 包含位于您定义的多边形内的图像 src1 部分。