带有opencv的Raspberry python脚本在启动时不会执行

我在Raspberry Pi 3上有一个Python 3脚本，它使用opencv 3.4从Logitech网络摄像头拍摄照片，然后将其上传到Dropbox . 代码改编自pyimageserach .

到目前为止，当我从终端或IDE手动执行脚本时，脚本可以正常工作 . 网络摄像头有时候不会 grab 图片，所以它进入循环但最终会起作用 . 但是，如果我使用其中一种方法在启动时自动加载它，代码什么都不做 .

#system append
    import sys
    sys.path.append('/home/pi/.local/lib/python3.5/site-packages/')
    sys.path.append('/usr/local/lib/python3.5/dist-packages/')

    import datetime
    import time
    import cv2
    import imutils
    import dropbox 
    #access dropbox
    client=dropbox.Dropbox("dropbox key not shown here")

    time.sleep(10)
    camera = cv2.VideoCapture(0)   
    # Initialize the first frame
    firstFrame = None #keep the first fram clean to compare to all others

    #loop over the frames of the video
    while True:
        (grabbed, frame) = camera.read()
         i = 1
         while grabbed != True:
               i = i+1
               print ("frame not grabbed")
               print ("Try AGAIN "+str(i)+" times in 15 seconds")
               camera = cv2.VideoCapture(0)
               time.sleep(15)
               (grabbed, frame) = camera.read()

         text = "Unoccupied Room"

    #resize the frame, convert it to grayscale, and blur it
    frame = imutils.resize(frame, width=500)
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) 
    gray = cv2.GaussianBlur(gray, (21,21), 0) 

    #if the first frame is None, initialize it
    if firstFrame is None:
         firstFrame = gray
         continue

     frameDelta = cv2.absdiff(firstFrame, gray) 
     thresh = cv2.threshold(frameDelta, 50, 255, cv2.THRESH_BINARY)[1] 

     # find contour of the image detected
     thresh = cv2.dilate(thresh, None, iterations=2)
     (_, cnts, _) = cv2.findContours(thresh.copy(), cv2.RETR_EXTERNAL, 
     cv2.CHAIN_APPROX_SIMPLE)



     # loop over the contours
     for c in cnts:
         # if the contour is too small, ignore it
        if cv2.contourArea(c) < 500:
              continue

        (x, y, w, h) = cv2.boundingRect(c)
        cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 2)
        text = "Occupied Room"


     #draw the text and time stamp on the frame
     cv2.putText(frame, "Room Status: {}".format(text), (10, 20), 
     cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 0, 255), 2)
     cv2.putText(frame, datetime.datetime.now().strftime("%A %d %B %Y 
     %I:%M:%S%p"), (10, frame.shape[0] - 10), cv2.FONT_HERSHEY_SIMPLEX, 
     0.35, (0, 0, 255), 1)

     # show the frame and record if the user presses a key
     cv2.imshow("Security Feed", frame)
     cv2.imshow("Thresh", thresh)
     cv2.imshow("Frame Delta", frameDelta)
     key = cv2.waitKey(1) & 0xFF

     # add my own stuff for occupied room
     if text == "Occupied Room":
     filename = 
     datetime.datetime.now().strftime('%Y%m%d_%Hh%Mm%Ss%f')+'.jpg'
     cv2.imwrite('./pictures/'+filename,frame)
     file_from = '/home/pi/Desktop/projects/pictures/'+filename
     file_to = '/pictures/'+filename

     try:
        with open (file_from, "rb") as file:
            client.files_upload(file.read(), file_to, mute=True)
        except ValueError:
             print ("Upload Failure")

        if key == ord("q"):
        # cleanup the camera and close any open window
            camera.release()
            del camera
            del frame
            del grabbed

            cv2.destroyAllWindows()
            break

除了告诉我有一个env变量问题，Crons没有做任何事情，我追加了 .

init.d没有用 .
rc.local没有用 .
我试图使用自动启动lxde，但这不起作用Bashrc简单工作我希望它可以工作而无需登录 .

我试过systemd并得到以下错误

Apr 12 01:24:50 raspberrypi python3.5 [743]：无法初始化服务器：无法连接：连接拒绝4月12日01:24:50 raspberrypi python3.5 [743]：无法打开显示：4月12日01： 24:50 raspberrypi systemd [1]：test.service：主进程退出，代码=退出，状态= 1 / FAILURE 4月12日01:24:50 raspberrypi systemd [1]：test.service：单元进入失败状态 . 4月12日01:24:50 raspberrypi systemd [1]：test.service：结果'退出代码'失败 .

看起来网络摄像头会短暂亮起然后消失

在其他时候使用systemd我得到视频错误V4L2的错误：opencv不支持传入图像的像素格式