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python opencv实现任意角度的透视变换实例代码

更新时间:2020-05-17 21:00:02 作者:startmvc
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-

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()

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