import cv2 as cv
import numpy as np

def measure_object(image):
    gray = cv.cvtColor(image, cv.COLOR_BGR2GRAY)
    ret, binary = cv.threshold(gray, 0, 255, cv.THRESH_BINARY | cv.THRESH_OTSU)
    print("threshold value : %s"%ret)
    cv.imshow("binary image",binary)
    dst = cv.cvtColor(binary, cv.COLOR_GRAY2BGR)
    outImage, contours, hireachy = cv.findContours(binary, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE)#輪廓  contours  層次資訊heriachy
    for i ,contour in enumerate(contours):
        area = cv.contourArea(contour)       #得到輪廓的面積
        x, y, w, h = cv.boundingRect(contour)        #矩形邊框包起來
        rate = min(w, h)/max(w, h)          #獲取輪廓比
        print("rectangle rate : %s"%rate)
        mm = cv.moments(contour)
        print(type(mm))
        cx = mm['m10'] / mm['m00']
        cy = mm['m01'] / mm['m00']
        cv.circle(dst, (np.int(cx), np.int(cy)), 3, (0, 255, 255), -1)
        # cv.rectangle(dst, (x, y), (x+w, y+h), (0, 0, 255), 2)
        print("contour area %s" % area)
        approxCurve = cv.approxPolyDP(contour, 4, True)        ##多多邊擬合函式
        print(approxCurve.shape)
        if approxCurve.shape[0] > 6:                             ##根據元件逼近approxCurve.shape[0] >6圓，=4矩形   =3三角形
            cv.drawContours(dst, contours, i, (0, 255, 0), 2)           ##提取輪廓
        if approxCurve.shape[0] == 4:
            cv.drawContours(dst, contours, i, (0, 0, 255), 2)
        if approxCurve.shape[0] == 3:
            cv.drawContours(dst, contours, i, (255, 0, 0), 2)
    cv.imshow("measure-contours", dst)

src = cv.imread("C:/Users/weiqiangwen/Desktop/sest/contours.png")
# cv.namedWindow("input contours",cv.WINDOW_AUTOSIZE)
cv.imshow("contours", src)
measure_object(src)
cv.waitKey(0)

cv.destroyAllWindows()