技術標籤：python

假設你得到了四個任意順序的座標,可以通過我編的程式獲得該矩形的長寬,角度和中心點

import cv2
import math


class Point(object):  # 座標類
    def __init__(self, xParam=0.0, yParam=0.0):
        self.x = xParam
        self.y = yParam

    def distance(self, pt):
        xDiff = self.x - pt.x
        yDiff = self.y - pt.y
        return math.sqrt(xDiff ** 2 + yDiff ** 2)

    def show(self):
        print("(%.2f, %.2f)" % (self.x, self.y))

    def substract(self, pt):  # 減法生成向量
        newPt = Point()
        xNew = self.x - pt.x
        yNew = self.y - pt.y
        return Point(xNew, yNew)

    def add(self, pt):  # 加法生成中心點
        newPt = Point()
        xNew = (self.x + pt.x) / 2
        yNew = (self.y + pt.y) / 2
        return Point(xNew, yNew)


# 求取兩個向量間的餘弦值
def cosVector(p1, p2):
    result1 = p1.x * p2.x + p1.y * p2.y  
    result2 = p1.x ** 2 + p1.y ** 2 
    result3 = p2.x ** 2 + p2.y ** 2  
    return result1 / ((result2 * result3) ** 0.5)



# 有向矩形的四個頂點輸入順序任意時，返回旋轉角度，w，h
def points_to_grasps(p, num=4, is_pos=True):  # 預設矩形框的w大於h
    res = []
    p = sorted(p, key=lambda Points: Points.x)  
    d12 = p[0].distance(p[1])
    d13 = p[0].distance(p[2])
    center_O = p[0].add(p[3])  
    vector_OB = Point(1, 0)  
    w = min(d12, d13)
    h = max(d12, d13)
    if d12 > d13:  
        point_A = p[1].add(p[3])
    else:
        if p[1].y < p[2].y:  
            point_A = p[2].add(p[3])
        else:  
            point_A = p[0].add(p[1])
    vector_OA = point_A.substract(center_O)  
    if is_pos:  
        cos_AOB = cosVector(vector_OA, vector_OB)
        box_class = cos_to_class(cos_AOB)
    else:
        box_class = 0
    res.append(str(center_O.x))
    res.append(str(center_O.y))
    res.append(str(w))
    res.append(str(h))
    res.append(str(box_class))
    return res
 

轉載請附上鍊接