opencv-Python旋转矩形框裁减

经常遇见旋转矩形框的裁减问题，那么思路是，将矩形框旋转正然后再裁减

# -*- coding:gb2312 -*-
import cv2
from math import *
import numpy as np
import time

def rotateImage(img,degree,pt1,pt2,pt3,pt4):
    height,width=img.shape[:2]
    heightNew = int(width * fabs(sin(radians(degree))) + height * fabs(cos(radians(degree))))
    widthNew = int(height * fabs(sin(radians(degree))) + width * fabs(cos(radians(degree))))
    matRotation=cv2.getRotationMatrix2D((width/2,height/2),degree,1)
    matRotation[0, 2] += (widthNew - width) / 2
    matRotation[1, 2] += (heightNew - height) / 2
    imgRotation = cv2.warpAffine(img, matRotation, (widthNew, heightNew), borderValue=(255, 255, 255))
    pt1 = list(pt1)
    pt3 = list(pt3)
    [[pt1[0]], [pt1[1]]] = np.dot(matRotation, np.array([[pt1[0]], [pt1[1]], [1]]))
    [[pt3[0]], [pt3[1]]] = np.dot(matRotation, np.array([[pt3[0]], [pt3[1]], [1]]))
    imgOut=imgRotation[int(pt1[1]):int(pt3[1]),int(pt1[0]):int(pt3[0])]
    cv2.imshow("imgOut",imgOut)  #裁减得到的旋转矩形框
    cv2.imwrite("imgOut.jpg",imgOut)
    # pt2 = list(pt2)
    # pt4 = list(pt4)
    # [[pt2[0]], [pt2[1]]] = np.dot(matRotation, np.array([[pt2[0]], [pt2[1]], [1]]))
    # [[pt4[0]], [pt4[1]]] = np.dot(matRotation, np.array([[pt4[0]], [pt4[1]], [1]]))
    # pt1 = (int(pt1[0]), int(pt1[1]))
    # pt2 = (int(pt2[0]), int(pt2[1]))
    # pt3 = (int(pt3[0]), int(pt3[1]))
    # pt4 = (int(pt4[0]), int(pt4[1]))
    # drawRect(imgRotation,pt1,pt2,pt3,pt4,(255,0,0),2)
    return imgRotation

def drawRect(img,pt1,pt2,pt3,pt4,color,lineWidth):
    cv2.line(img, pt1, pt2, color, lineWidth)
    cv2.line(img, pt2, pt3, color, lineWidth)
    cv2.line(img, pt3, pt4, color, lineWidth)
    cv2.line(img, pt1, pt4, color, lineWidth)


if __name__=="__main__":
    startTime=time.time()
    imgSrc=cv2.imread('E:\桌面\lena.jpg')
    imgResize=cv2.resize(imgSrc,(500,500))
    pt1=(100,100)
    pt2=(150,50)
    pt3=(175,75)
    pt4=(125,125)
    # drawRect(imgResize,pt1,pt2,pt3,pt4,(0,0,255),2)
    imgRotation=rotateImage(imgResize,-degrees(atan2(50,50)),pt1,pt2,pt3,pt4)
    endTime = time.time()
    print endTime-startTime
    cv2.imshow("imgRotation",imgRotation)
    cv2.imwrite("imgRotation.jpg",imgRotation)
    cv2.waitKey(0)