图像复合变换

import cv2
import numpy as np
from matplotlib import pyplot as plt  
img=cv2.imread('C:/Users/xpp/Desktop/Lena.png') 
height,width=img.shape[:2]
fx,fy=0.6,0.6#图像缩放比例
MAZ=np.float32([[fx,0,0],[0,fy,0]])#构造缩放变换矩阵
imgT1=cv2.warpAffine(img,MAZ,(width,height))#仿射变换, 黑色填充
dx,dy=50,200#dx=100向右偏移量,dy=50向下偏移量
MAT=np.float32([[1,0,dx],[0,1,dy]])#构造平移变换矩阵
imgT2=cv2.warpAffine(imgT1,MAT,(width,height),borderValue=(0,255,255))#实现仿射变换
theta=-30*np.pi/180#逆时针旋转 30°
cosTheta=np.cos(theta)
sinTheta=np.sin(theta)
MAR = np.float32([[cosTheta,-sinTheta,0],[sinTheta,cosTheta,0]])#构造旋转变换矩阵
imgT3=cv2.warpAffine(imgT2,MAR,(width,height),borderValue=(255,255,0))#实现仿射变换
theta=-30*np.pi/180#逆时针扭变 30°
MAS=np.float32([[1,np.tan(theta),0],[0,1,0]])#构造扭变变换矩阵
imgT4=cv2.warpAffine(imgT3,MAS,(width,height),borderValue=(255,0,255))#实现仿射变换
plt.figure(figsize=(9,6))
plt.subplot(221),plt.axis('off'),plt.title("T1:Zoom")
plt.imshow(cv2.cvtColor(imgT1, cv2.COLOR_BGR2RGB)),
plt.subplot(222),plt.axis('off'),plt.title("T2:Translation")
plt.imshow(cv2.cvtColor(imgT2, cv2.COLOR_BGR2RGB))
plt.subplot(223),plt.axis('off'),plt.title("T3:Rotation")
plt.imshow(cv2.cvtColor(imgT3, cv2.COLOR_BGR2RGB))
plt.subplot(224),plt.axis('off'),plt.title("T4:Shear")
plt.imshow(cv2.cvtColor(imgT4, cv2.COLOR_BGR2RGB))
plt.show()