import cv2
import numpy as np
low_h = np.array([93, 100, 90])  #设置象棋hsv的上下阈值
high_h = np.array([104, 160, 130])
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE,(5,5))  #设定高斯滤波的卷积核
img = cv2.imread('xiangqi1.jpg')
Hsv = cv2.cvtColor(img, cv2.COLOR_RGB2HSV)  #将jpg格式的图片通过颜色空间转换为HSV
ghsv = cv2.GaussianBlur(Hsv,(3,3),0)       #高斯模糊
mask = cv2.inRange(ghsv,low_h,high_h)     #通过inRange()函数将low之下high以上的颜色擦除
mask = cv2.morphologyEx(mask, cv2.MORPH_OPEN, kernel)
mask = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, kernel)    #闭运算和开运算除去象棋以外的噪点
contours, hierarchy = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)  #findcontours查找角点
for c in contours:
    x, y,w,h = cv2.boundingRect(c)  #得到角点的左上角坐标和矩形的长宽
    if(w*h>10000):
        cv2.rectangle(img,(x,y),(x+w,y+h),(0,0,255),2)   #画图
cv2.imshow('img',img)
#cv2.imshow('mask',mask)
cv2.waitKey(0)
cv2.destroyAllWindows()

import cv2
import numpy as np
cat = cv2.VideoCapture(0)
low_h = np.array([93, 100, 90])
high_h = np.array([103, 160, 130])
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE,(5,5))
def corner(img):
    hsv = cv2.cvtColor(img, cv2.COLOR_RGB2HSV)
    ghsv = cv2.GaussianBlur(hsv, (3, 3), 0)
    mask = cv2.inRange(ghsv, low_h, high_h)
    mask = cv2.morphologyEx(mask, cv2.MORPH_OPEN, kernel)  #开运算
    mask = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, kernel)  #闭运算
    contours, hierarchy = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
    return contours
def draw(contours, img):
    for c in contours:
        x, y, w, h = cv2.boundingRect(c)
        if cv2.contourArea(c) > 400:
            print('x:',x,'y:',y)
            cv2.rectangle(img, (x, y), (x+w, y+h), (0, 0, 255), 2)
        else:
            continue
    return img
while True:
    ret, frame = cat.read()
    if not ret:
        break
    contours = corner(frame)
    img = draw(contours, frame)
    cv2.imshow('img', img)
    if cv2.waitKey(10) == ord('q'):
        break
cv2.destroyAllWindows()