本文实例为大家分享了python opencv实现旋转矩形框裁减的具体代码，供大家参考，具体内容如下

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 cv2from math import *import numpy as npimport timedef 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 imgRotationdef 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)

效果图：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。