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flip the image
Image flipping can be achieved using cv2.filp in opencv
def flip(src, flipCode, dst=None)- src: input image
- flipCode: flipCode A flag to specify how to flip the array; 0 means flip up and down, a positive number means flip left and right, and a negative number means flip both up and down.
- dst: output image
The code below rotates the image differently.
import cv2
import numpy as np
lp = cv2.resize(cv2.imread('../images/lp.jpg'), None, fx=0.7, fy=0.7)
# 翻转 0表示上下，正数表示左右，负数表示上下左右都翻转
new_lp1 = cv2.flip(lp, 0)
new_lp2 = cv2.flip(lp, 1)
new_lp3 = cv2.flip(lp, -1)
cv2.imshow('lp', np.hstack((lp, new_lp1, new_lp2, new_lp3)))
cv2.waitKey(0)
cv2.destroyAllWindows()
Image rotation
Image rotation using cv2.rotate in opencv
def rotate(src, rotateCode, dst=None)- src: input image
- rotateCode: flip angle, 3 options, 90 degrees, 180 degrees, 270 degrees
- dst: output image
The options for rotateCode are as follows
| parameter | describe |
|---|---|
| ROTATE_90_CLOCKWISE | Rotate 90 degrees clockwise |
| ROTATE_180 | Rotate 180 degrees |
| ROTATE_90_COUNTERCLOCKWISE | Rotate 90 degrees counterclockwise, which is 270 degrees clockwise |
The following code uses 3 parameters
import cv2
lp = cv2.resize(cv2.imread('../images/lp.jpg'), None, fx=0.7, fy=0.7)
# 平移 3种旋转，使用cv2.ROTATE_xxx进行选择
lp1 = cv2.rotate(lp, cv2.ROTATE_90_CLOCKWISE)
lp2 = cv2.rotate(lp, cv2.ROTATE_90_COUNTERCLOCKWISE)
lp3 = cv2.rotate(lp, cv2.ROTATE_180)
cv2.imshow('lp', lp)
cv2.imshow('lp1', lp1)
cv2.imshow('lp2', lp2)
cv2.imshow('lp3', lp3)
cv2.waitKey(0)
cv2.destroyAllWindows()
