使用open cv进行角度测量

用了一点初中数学的知识，准确度，跟鼠标点的准不准有关系，话不多说直接上代码

import cv2
import math

path = "test.jpg"
img = cv2.imread(path)
pointsList = []


def mousePoint(event, x, y, flags, params):
    # 如果鼠标左键按下
    if event == cv2.EVENT_LBUTTONDOWN:
        size = len(pointsList)
        if size != 0 and size % 3 != 0:
            cv2.line(img, tuple(pointsList[round((size - 1)/3) * 3]), (x, y), (0, 0, 255), 2)
        cv2.circle(img, (x, y), 5, (0, 0, 255), cv2.FILLED)
        pointsList.append([x, y])


# 计算斜率
def gradient(pt1, pt2):
    return (pt2[1] - pt1[1])/(pt2[0] - pt1[0])

def getAngle(pointsList):
    # 最后三个点
    pt1, pt2, pt3 = pointsList[-3:]
    # 计算两条直线的斜率
    m1 = gradient(pt1, pt2)
    m2 = gradient(pt1, pt3)
    angR = math.atan((m2 - m1)/(1 + (m2 * m1)))
    # 去掉小数,将弧度转换成角度
    angD = round(math.degrees(angR))
    cv2.putText(img, str(angD), ((pt1[0] - 40), pt1[1] - 20), cv2.FONT_HERSHEY_COMPLEX, 1.5, (0, 0, 255), 2)

while True:

    if len(pointsList) % 3 == 0 and len(pointsList) != 0:
        getAngle(pointsList)
    cv2.imshow("Image", img)
    # 设置鼠标回调函数
    cv2.setMouseCallback("Image", mousePoint)
    # 是否在1毫秒内按下了'q'键
    if cv2.waitKey(1) & 0xFF == ord('q'):
        pointsList = []
        img = cv2.imread(path)

效果