chess_detection.py 文件源码

def get_chessboard_lines(binary_img):
    edges = cv2.Canny(binary_img,50,120)
    cv2.imshow('image',edges)
    k = cv2.waitKey(0) & 0xFF
    if k == 27:
        cv2.destroyAllWindows()
    lines_data = cv2.HoughLines(edges,1,np.pi/180,110)

    parallel_lines = []
    vertical_lines = []
    for rho,theta in lines_data[0]:
        #print 'rho:  '+str(rho)+'theta:  '+str(theta)
        if 2>theta > 1:
            vertical_lines.append([theta,rho])
        elif theta < 1 :
            parallel_lines.append([theta,rho])
        elif theta>3:
            parallel_lines.append([theta,rho])

        a = np.cos(theta)
        b = np.sin(theta)
        x0 = a*rho
        y0 = b*rho
        x1 = int(x0 + 1000*(-b))
        y1 = int(y0 + 1000*(a))
        x2 = int(x0 - 1000*(-b))
        y2 = int(y0 - 1000*(a))
        cv2.line(edges,(x1,y1),(x2,y2),(255,0,0),2)
    cv2.imshow('image',edges)
    k = cv2.waitKey(0) & 0xFF
    if k == 27:
        cv2.destroyAllWindows()

    vertical_lines=sorted(vertical_lines,key=lambda x: abs(x[1]))
    parallel_lines=sorted(parallel_lines,key=lambda x: abs(x[1]))
    return vertical_lines,parallel_lines