圖像的幾何變換

3.圖像的旋轉(zhuǎn)

圖像的旋轉(zhuǎn)就是讓圖像按照某一點(diǎn)旋轉(zhuǎn)到指定的角度。需要確定3個(gè)參數(shù)：圖像的旋轉(zhuǎn)中心、旋轉(zhuǎn)角度和縮放因子。在openv中通過(guò)getRotationMatrix2D()函數(shù)來(lái)實(shí)現(xiàn)圖像的旋轉(zhuǎn)。

import cv2
import numpy as npimgpath = "images/img1.jpg"
img = cv2.imread(imgpath, 1) 
img = cv2.resize(img, (0, 0), fx=0.5, fy=0.5) 
height, width = img.shape[:2]# 得到變換矩陣
M = cv2.getRotationMatrix2D((width/2, height/2), 45, 1)  #中心旋轉(zhuǎn)45度，不縮放
# 旋轉(zhuǎn)變換
translated_img = cv2.warpAffine(img, M, (width, height))
cv2.imshow('Original Image', img)
cv2.imshow('Translated Image', translated_img)
cv2.waitKey(0)

4.圖像的鏡像變換

圖像的鏡像變換分為兩種：水平鏡像和垂直鏡像。在opencv中通過(guò)flip()函數(shù)實(shí)現(xiàn)。

import cv2
import numpy as npimgpath = "images/img1.jpg"
img = cv2.imread(imgpath, 1) 
img = cv2.resize(img, (0, 0), fx=0.25, fy=0.25) x_img = cv2.flip(img, 1)  #X軸，水平翻轉(zhuǎn)
y_img = cv2.flip(img, 0)  #Y洲，垂直翻轉(zhuǎn)
xy_img = cv2.flip(img, -1)#水平垂直同時(shí)翻轉(zhuǎn)
cv2.imshow("img", img)
cv2.imshow("x_img", x_img)
cv2.imshow("y_img", y_img)
cv2.imshow("xy_img", xy_img)
cv2.waitKey(0)