为什么该程序没有打开任何窗口

如何解决为什么该程序没有打开任何窗口

import cv2
import numpy as np
import math

cap = cv2.VideoCapture(0)

while (1):

    try:  # an error comes if it does not find anything in window as it cannot find contour of max area
        # therefore this try error statement

        ret,frame = cap.read()
        frame = cv2.flip(frame,1)
        kernel = np.ones((3,3),np.uint8)

        # define region of interest
        roi = frame[100:300,100:300]

        cv2.rectangle(frame,(100,100),(300,300),(0,255,0),0)
        hsv = cv2.cvtColor(roi,cv2.COLOR_BGR2HSV)

        # define range of skin color in HSV
        lower_skin = np.array([0,20,70],dtype=np.uint8)
        upper_skin = np.array([20,255],dtype=np.uint8)

        # extract skin colur imagw
        mask = cv2.inRange(hsv,lower_skin,upper_skin)

        # extrapolate the hand to fill dark spots within
        mask = cv2.dilate(mask,kernel,iterations=4)

        # blur the image
        mask = cv2.GaussianBlur(mask,(5,5),100)

        # find contours
        _,contours,hierarchy = cv2.findContours(mask,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)

        # find contour of max area(hand)
        cnt = max(contours,key=lambda x: cv2.contourArea(x))

        # approx the contour a little
        epsilon = 0.0005 * cv2.arcLength(cnt,True)
        approx = cv2.approxPolyDP(cnt,epsilon,True)

        # make convex hull around hand
        hull = cv2.convexHull(cnt)

        # define area of hull and area of hand
        areahull = cv2.contourArea(hull)
        areacnt = cv2.contourArea(cnt)

        # find the percentage of area not covered by hand in convex hull
        arearatio = ((areahull - areacnt) / areacnt) * 100

        # find the defects in convex hull with respect to hand
        hull = cv2.convexHull(approx,returnPoints=False)
        defects = cv2.convexityDefects(approx,hull)

        # l = no. of defects
        l = 0

        # code for finding no. of defects due to fingers
        for i in range(defects.shape[0]):
            s,e,f,d = defects[i,0]
            start = tuple(approx[s][0])
            end = tuple(approx[e][0])
            far = tuple(approx[f][0])
            pt = (100,180)

            # find length of all sides of triangle
            a = math.sqrt((end[0] - start[0]) ** 2 + (end[1] - start[1]) ** 2)
            b = math.sqrt((far[0] - start[0]) ** 2 + (far[1] - start[1]) ** 2)
            c = math.sqrt((end[0] - far[0]) ** 2 + (end[1] - far[1]) ** 2)
            s = (a + b + c) / 2
            ar = math.sqrt(s * (s - a) * (s - b) * (s - c))

            # distance between point and convex hull
            d = (2 * ar) / a

            # apply cosine rule here
            angle = math.acos((b ** 2 + c ** 2 - a ** 2) / (2 * b * c)) * 57

            # ignore angles > 90 and ignore points very close to convex hull(they generally come due to noise)
            if angle <= 90 and d > 30:
                l += 1
                cv2.circle(roi,far,3,[255,0],-1)

            # draw lines around hand
            cv2.line(roi,start,end,[0,2)

        l += 1

        # print corresponding gestures which are in their ranges
        font = cv2.FONT_HERSHEY_SIMPLEX
        if l == 1:
            if areacnt < 2000:
                cv2.putText(frame,'Put hand in the box',50),font,2,255),cv2.LINE_AA)
            else:
                if arearatio < 12:
                    cv2.putText(frame,'0',cv2.LINE_AA)
                elif arearatio < 17.5:
                    cv2.putText(frame,'Best of luck',cv2.LINE_AA)

                else:
                    cv2.putText(frame,'1',cv2.LINE_AA)

        elif l == 2:
            cv2.putText(frame,'2',cv2.LINE_AA)

        elif l == 3:

            if arearatio < 27:
                cv2.putText(frame,'3',cv2.LINE_AA)
            else:
                cv2.putText(frame,'ok',cv2.LINE_AA)

        elif l == 4:
            cv2.putText(frame,'4',cv2.LINE_AA)

        elif l == 5:
            cv2.putText(frame,'5',cv2.LINE_AA)

        elif l == 6:
            cv2.putText(frame,'reposition',cv2.LINE_AA)

        else:
            cv2.putText(frame,(10,cv2.LINE_AA)

        # show the windows
        cv2.imshow('mask',mask)
        cv2.waitKey(0)
        cv2.imshow('frame',frame)
    except:
        pass

    k = cv2.waitKey(5) & 0xFF
    if k == 27:
        break

cv2.destroyAllWindows()
cap.release()

这是用于手势识别的代码。当我运行它时，没有窗口打开。

我甚至在接近尾声的cv2.imshow（）语句之后尝试了cv2.waitKey（）和cv2.waitKey（0）。但仍然没有任何窗户在打开。

我还检查了所有权限。

我应该怎么做？

而且，此代码用于一只手的手势识别。如果我想让它同时识别两只手该怎么办？

谢谢。