Opencv-python实⽤教程
opencv ⼩tips
pdf 路径 D:\2_Noteexpress数据库\fulltext\电⼦书\CV\Practical Python and OpenCV by Adrian Rosebrock ().pdf 6.1 Image Transformations
6.1.1 Translation 函数的⽤法，该函数可以将图像前后左右移动，重点关注M矩阵。
1import numpy as np
2import argparse
3import imutils
4import cv2
56
ap = argparse.ArgumentParser()
7 ap.add_argument("-i","--image", required =True,
8help="Path to the image")
9 args =vars(ap.parse_args())
10
11 image = cv2.imread(args["image"])
12 cv2.imshow("Original", image)
13
14 M = np.float32([[1,0,25],[0,1,50]])
15 shifted = cv2.warpAffine(image, M,(image.shape[1], image.shape
[0]))
16 cv2.imshow("Shifted Down and Right", shifted)
17
18 M = np.float32([[1,0,-50],[0,1,-90]])
19 shifted = cv2.warpAffine(image, M,(image.shape[1], image.shaperides数据库持久化
[0]))
20 cv2.imshow("Shifted Up and Left", shifted)
辅助函数
1import numpy as np
2import cv2
3
4def translate(image, x, y):
5    M = np.float32([[1,0, x],[0,1, y]])
6    shifted = cv2.warpAffine(image, M,(image.shape[1], image.shape[0]))
7return shifted
translation.py
21 shifted = anslate(image,0,100)
22 cv2.imshow("Shifted Down", shifted)
23 cv2.waitKey(0)
Top-Left: Our original T-Rex image.
Top-Right: Translating our image 25
pixels to the right and 50 pixels
down. Bottom-Left: Shifting T-Rex
50 pixels to the left and 90 pixels up. Bottom-Right: Shifting the T-Rex down using our convenience
method
6.1.2 Rotation
1import numpy as np
2import argparse
3import imutils
python基础教程电子书154import cv2
枚举类型
56
ap = argparse.ArgumentParser()
7 ap.add_argument("-i","--image", required =True,
8help="Path to the image")
9 args =vars(ap.parse_args())
10
11 image = cv2.imread(args["image"])
12 cv2.imshow("Original", image)
jsoup爬虫遇到验证码怎么办13
14(h, w)= image.shape[:2]
15 center =(w //2, h //2)
16
17 M = RotationMatrix2D(center,45,1.0)
18 rotated = cv2.warpAffine(image, M,(w, h))
19 cv2.imshow("Rotated by 45 Degrees", rotated)
20
solr的使用21 M = RotationMatrix2D(center,-90,1.0)
22 rotated = cv2.warpAffine(image, M,(w, h))
23 cv2.imshow("Rotated by -90 Degrees", rotated)
27def rotate(image, angle, center =None, scale =1.0): 28(h, w)= image.shape[:2]
织梦3d模型模板29
30if center is None:
31 center =(w /2, h /2)
32
33 M = RotationMatrix2D(center, angle, scale)
34 rotated = cv2.warpAffine(image, M,(w, h))
35return rotated
Top-Left: Our original T-Rex image.
Top-Right: Rotating the image by 45
degrees. Bottom-Left: Rotating the
image by −90 degrees. Bottom-Right:
Flipping T-Rex upside down by rotating the image by 180 degrees.

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