Python opencv操作深入详解

直接读取图片

1. def display_img(file="p.jpeg"):
2. img = cv.imread(file)
3. print (img.shape)
4. cv.imshow('image',img)
5. cv.waitKey(0)
6. cv.destroyAllWindows()

读取灰度图片

1. def display_gray_img(file="p.jpeg"):
2. img = cv.imread(file,cv.IMREAD_GRAYSCALE)
3. print (img.shape)
4. cv.imshow('image',img)
5. cv.waitKey(0)
6. cv.destroyAllWindows()
7. cv.imwrite("gray_img.png",img)

读取视频

1. def display_video(file="sj.mp4"):
2. v = cv.VideoCapture(file)
3. if v.isOpened():
4. open,frame = v.read()
5. else:
6. open=False
7.  
8. while open:
9. ret,frame = v.read()
10. if frame is None:
11. break
12.  
13. if ret == True:
14. gray = cv.cvtColor(frame,cv.COLOR_BGR2GRAY)
15. cv.imshow("result",gray)
16. if cv.waitKey(10) & 0xFF == 27:
17. break
18. v.release()
19. v.waitKey(0)
20. v.destroyAllWindows()

截取图片

1. def get_frame_img(file="p.jpeg"):
2. img = cv.imread(file)
3. print (img.shape)
4. cat = img[0:200,0:200]
5. cv.imshow('get_frame_img',cat)
6. cv.waitKey(0)
7. cv.destroyAllWindows()

提取rgb通道

1. def extrats_rgb_img(file="p.jpeg"):
2. img = cv.imread(file)
3. b,g,r = cv.split(img)
4. print (b.shape,g.shape,r.shape)
5. new_img = cv.merge((b,g,r))
6. print (new_img.shape)
7.  
8. copy_img_r = img.copy()
9. copy_img_r[:,:,0]=0
10. copy_img_r[:,:,1]=0
11. cv.imshow("r_img",copy_img_r)
12.  
13. copy_img_g = img.copy()
14. copy_img_g[:,:,0]=0
15. copy_img_g[:,:,2]=0
16. cv.imshow("g_img",copy_img_g)
17.  
18. copy_img_b = img.copy()
19. copy_img_b[:,:,1]=0
20. copy_img_b[:,:,2]=0
21. cv.imshow("b_img",copy_img_b)

边界填充

1. def border_fill_img(file="p.jpeg"):
2. border_type = [
3. cv.BORDER_REPLICATE,#复制法，复制边缘
4. cv.BORDER_REFLECT, #反射法，对感兴趣的图像中的像素在两边进行复制
5. cv.BORDER_REFLECT_101,#反射法，以边缘像素为轴，对称
6. cv.BORDER_WRAP,#外包装法
7. cv.BORDER_CONSTANT#常量法，常量填充
8. ]
9. border_title = [
10. "REPLICATE",
11. "REFLECT",
12. "REFLECT_101",
13. "WRAP",
14. "CONSTANT"
15. ]
16. img = cv.imread(file)
17. top_size,bottom_size,left_size,right_size = (50,50,50,50)
18. plt.subplot(231)
19. plt.imshow(img,"gray")#原始图像
20. plt.title("ORIGNAL")
21.  
22. for i in range(len(border_type)):
23. result = cv.copyMakeBorder(img,top_size,bottom_size,left_size,right_size,border_type[i])
24. plt.subplot(232+i)
25. plt.imshow(result,"gray")
26. plt.title(border_title[i])
27.  
28. plt.show()

图像融合，变换

1. def img_compose(file1="tu.jpeg",file2="gui.jpeg"):
2. img_1 = cv.imread(file1)
3. img_2 = cv.imread(file2)
4. print (img_1.shape)
5. print (img_2.shape)
6. img_1= cv.resize(img_1,(500,500))
7. img_2= cv.resize(img_2,(500,500))
8. print (img_1.shape)
9. print (img_2.shape)
10. res = cv.addWeighted(img_1,0.4,img_2,0.6,0)
11. plt.imshow(res)
12. plt.show()
13.  
14. res = cv.resize(img_1,(0,0),fx=3,fy=1)
15. plt.imshow(res)
16. plt.show()
17.  
18. res = cv.resize(img_2,(0,0),fx=1,fy=3)
19. plt.imshow(res)
20. plt.show()

二值化处理

1. def Binarization(filepath):
2. img = cv2.imread(filepath,0)
3. limit = 120
4. ret,thresh=cv2.threshold(img,limit,255,cv2.THRESH_BINARY_INV)
5. plt.imshow(thresh,'gray')
6. plt.show()
7. return thresh
8. Binarization('t1.jpg')

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原文链接：https://blog.csdn.net/qq_38641985/article/details/115023738