python opencv实现任意角度的透视变换实例代码

本文主要分享的是一则python+opencv实现任意角度的透视变换的实例，具体如下：

# -*- coding:utf-8 -*-
import cv2
import numpy as np

def rad(x):
 return x * np.pi / 180

img = cv2.imread("6.jfif")
cv2.imshow("original", img)

# 扩展图像，保证内容不超出可视范围
img = cv2.copyMakeBorder(img, 200, 200, 200, 200, cv2.BORDER_CONSTANT, 0)
w, h = img.shape[0:2]

anglex = 0
angley = 30
anglez = 0 #是旋转
fov = 42
while 1:
 # 镜头与图像间的距离，21为半可视角，算z的距离是为了保证在此可视角度下恰好显示整幅图像
 z = np.sqrt(w ** 2 + h ** 2) / 2 / np.tan(rad(fov / 2))
 # 齐次变换矩阵
 rx = np.array([[1, 0, 0, 0],
         [0, np.cos(rad(anglex)), -np.sin(rad(anglex)), 0],
         [0, -np.sin(rad(anglex)), np.cos(rad(anglex)), 0, ],
         [0, 0, 0, 1]], np.float32)

ry = np.array([[np.cos(rad(angley)), 0, np.sin(rad(angley)), 0],
         [0, 1, 0, 0],
         [-np.sin(rad(angley)), 0, np.cos(rad(angley)), 0, ],
         [0, 0, 0, 1]], np.float32)

rz = np.array([[np.cos(rad(anglez)), np.sin(rad(anglez)), 0, 0],
         [-np.sin(rad(anglez)), np.cos(rad(anglez)), 0, 0],
         [0, 0, 1, 0],
         [0, 0, 0, 1]], np.float32)

r = rx.dot(ry).dot(rz)

# 四对点的生成
 pcenter = np.array([h / 2, w / 2, 0, 0], np.float32)

p1 = np.array([0, 0, 0, 0], np.float32) - pcenter
 p2 = np.array([w, 0, 0, 0], np.float32) - pcenter
 p3 = np.array([0, h, 0, 0], np.float32) - pcenter
 p4 = np.array([w, h, 0, 0], np.float32) - pcenter

dst1 = r.dot(p1)
 dst2 = r.dot(p2)
 dst3 = r.dot(p3)
 dst4 = r.dot(p4)

list_dst = [dst1, dst2, dst3, dst4]

org = np.array([[0, 0],
         [w, 0],
         [0, h],
         [w, h]], np.float32)

dst = np.zeros((4, 2), np.float32)

# 投影至成像平面
 for i in range(4):
   dst[i, 0] = list_dst[i][0] * z / (z - list_dst[i][2]) + pcenter[0]
   dst[i, 1] = list_dst[i][1] * z / (z - list_dst[i][2]) + pcenter[1]

warpR = cv2.getPerspectiveTransform(org, dst)

result = cv2.warpPerspective(img, warpR, (h, w))
 cv2.imshow("result", result)
 c = cv2.waitKey(30)

# anglex += 3      #auto rotate
 # anglez += 1       #auto rotate
 # angley += 2      #auto rotate

# 键盘控制
 if 27 == c: # Esc quit
   break;
 if c == ord('w'):
   anglex += 1
 if c == ord('s'):
   anglex -= 1
 if c == ord('a'):
   angley += 1
   # dx=0
 if c == ord('d'):
   angley -= 1
 if c == ord('u'):
   anglez += 1
 if c == ord('p'):
   anglez -= 1
 if c == ord('t'):
   fov += 1
 if c == ord('r'):
   fov -= 1
 if c == ord(' '):
   anglex = angley = anglez = 0
 if c == ord('q'):
   print("======================================")
   print('旋转矩阵：\n', r)
   print("angle alpha: ", anglex, 'angle beta: ', angley, "dz: ", anglez, ": ", z)

cv2.destroyAllWindows()

来源：http://blog.csdn.net/jacke121/article/details/78996288