opencv-python图像透视变换cv2.warpperspective
代码如下:
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# -*- coding:utf-8 -*-
import cv2
import numpy as np
import sys
img = cv2.imread( 'test.jpg' )
# cv2.imshow("original", img)
# 可选,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
r = 0
def rad(x):
return x * np.pi / 180
def get_warpr():
global anglex,angley,anglez,fov,w,h,r
# 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)
return warpr
def control():
global anglex,angley,anglez,fov,r
# 键盘控制
if 27 = = c: # esc quit
sys.exit()
if c = = ord ( 'w' ):
anglex + = 1
if c = = ord ( 's' ):
anglex - = 1
if c = = ord ( 'a' ):
angley + = 1
print (angley)
# 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 ( 'e' ):
print ( "======================================" )
print ( 'rotation matrix:' )
print (r)
print ( 'angle alpha(anglex):' )
print (anglex)
print ( 'angle beta(angley):' )
print (angley)
print ( 'dz(anglez):' )
print (anglez)
while true:
warpr = get_warpr()
result = cv2.warpperspective(img, warpr, (h, w))
cv2.namedwindow( 'result' , 2 )
cv2.imshow( "result" , result)
c = cv2.waitkey( 30 )
control()
cv2.destroyallwindows()
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运行效果:
控制:
- s控制垂直方向上的形变
- a和d控制水平方向上的行变
- u和p控制角度旋转
- e 输出当前旋转矩阵参数
总结
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原文链接:https://blog.csdn.net/dcrmg/article/details/80273818