python使用opencv处理视频流调用cv2.resizeWindow方法报错？

Question

错误信息如下：
Traceback (most recent call last):
File "./tools/test.py", line 36, in
cv2.resizeWindow("enhanced", 640, 360);
cv2.error: OpenCV(4.1.0) /io/opencv/modules/highgui/src/window_QT.cpp:592: error: (-27:Null pointer) NULL guiReceiver (please create a window) in function 'cvResizeWindow'

代码：

# -*- coding: utf-8 -*-



import PIL

import cv2



if __name__ == '__main__':

    writeVideo_flag = True 

    video_src = "rtsp://admin:Admin123@85.18.13.222"

    video_capture = cv2.VideoCapture(video_src)

    source_file = '/approot1/ioth/ai/tf-faster-rcnn-master'

    print(video_capture.isOpened())

    if writeVideo_flag:

    # 将检测的视频结果输出到output.avi,detection.txt

    # Define the codec and create VideoWriter object

        w = int(video_capture.get(3))

    print(w)

        h = int(video_capture.get(4))

    print(h)

        fourcc = cv2.VideoWriter_fourcc(*'MJPG')

        out = cv2.VideoWriter(source_file + '/img/output.avi', fourcc, 15, (w, h))

        list_file = open(source_file + '/img/detection.txt', 'w')

        frame_index = -1 



    fps = 0.0

    fpscount = 0





    #while True:

    ret, frame = video_capture.read()  # frame shape 640*480*3

    print(frame)

    while True:



        if ret == True:

            #窗口可以随意调整大小
                        #这行报错
            cv2.resizeWindow("detect Inout", 640, 360);

            fpscount += 1

        else:

            break;

        if fpscount % 1 == 0:

            image = PIL.Image.fromarray(frame)

Answer 1

在前面加一行
cv2.namedWindow('detect Inout',0)