Python OpenCv 仿射变换、平移、旋转、缩放、透视变换

仿射变换

import cv2
import numpy

img = cv2.imread("D:/test123.png")
rows, cols = img.shape[:2]
p1 = numpy.float32([[0, 0], [cols - 1, 0], [0, rows - 1]])
p2 = numpy.float32([[0, rows * 0.3], [cols * 0.8, rows * 0.5], [cols * 0.2, rows * 0.7]])

M = cv2.getAffineTransform(p1, p2)
res = cv2.warpAffine(img, M, (cols, rows))

cv2.imshow("测试1", img)
cv2.imshow("测试2", res)

cv2.waitKey()
cv2.destroyAllWindows()

平移

import cv2
import numpy

img = cv2.imread("D:/test11.png")
rows, cols = img.shape[:2]
p1 = numpy.float32([[0, 0], [cols - 1, 0], [0, rows - 1]])
p2 = numpy.float32([[25, 40], [cols - 1 + 25, 40], [25, rows - 1 + 40]])

M = cv2.getAffineTransform(p1, p2)
res = cv2.warpAffine(img, M, (cols, rows))

cv2.imshow("测试1", img)
cv2.imshow("测试2", res)

cv2.waitKey()
cv2.destroyAllWindows()

平移快捷方式

import cv2
import numpy

img = cv2.imread("D:/test11.png")
rows, cols = img.shape[:2]
M = numpy.float32([[1, 0, 25], [0, 1, 40]])
res = cv2.warpAffine(img, M, (cols, rows))

cv2.imshow("测试1", img)
cv2.imshow("测试2", res)

cv2.waitKey()
cv2.destroyAllWindows()

旋转

import cv2
import numpy

img = cv2.imread("D:/test11.png")
rows, cols = img.shape[:2]
p1 = numpy.float32([[0, 0], [cols - 1, 0], [0, rows - 1]])
p2 = numpy.float32([[25, 40], [cols - 1 + 25, 40], [25, rows - 1 + 40]])

M = cv2.getRotationMatrix2D((cols / 2, rows / 2), 45, 1)#中心点, 45°角, 缩放比例1
res = cv2.warpAffine(img, M, (cols, rows))

cv2.imshow("测试1", img)
cv2.imshow("测试2", res)

cv2.waitKey()
cv2.destroyAllWindows()

缩放

import cv2

img = cv2.imread("D:/test11.png")
res = cv2.resize(img, (300, 200))

cv2.imshow("测试1", img)
cv2.imshow("测试2", res)

cv2.waitKey()
cv2.destroyAllWindows()

透视变换

import cv2
import numpy

img = cv2.imread("D:/test11.png")
rows, cols = img.shape[:2]
p1 = numpy.float32([[0, 0], [cols - 1, 0], [0, rows - 1], [cols - 1, rows - 1]])
p2 = numpy.float32([[0, rows * 0.3], [cols * 0.8, rows * 0.5], [cols * 0.2, rows * 0.7], [cols * 0.8, rows * 0.8]])

M = cv2.getPerspectiveTransform(p1, p2)
res = cv2.warpPerspective(img, M, (cols, rows))

cv2.imshow("测试1", img)
cv2.imshow("测试2", res)

cv2.waitKey()
cv2.destroyAllWindows()