python opencv 实现任意角度的透视变换

# -*- 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()