python、cv2.imshow()、raspberryPi和黑屏

目前正在尝试使用GUI编写代码,该GUI将允许打开/关闭图像处理。理想情况下,代码将允许打开/关闭窗口视图、实时图像处理(相当基本)和控制外部板。

我遇到的问题是围绕着 cv2.imshow() 功能。几个月前,我通过从 picamera 到 cv2 在这里我可以执行更复杂的计算,比如背景减法,而不必一直调用python。使用 cv2型 .

快进6个月,在尝试更新代码时,我发现 cv2.imshow() bcm2835-v4l2型 cv2.imshow() 或者我猜是这样。

threading 我想知道这是否是罪魁祸首。我不这么认为,虽然在输入命令

import cv2
camera = cv2.VideoCapture(0)
grabbed,frame = camera.read()
cv2.imshow(frame)

产生相同的黑屏

下面是我正在使用的代码(在RPi3上),一些图片显示了错误和预期结果。

Raspberry pi3
raspi stretch
python 3.5.1
opencv 3.4.1

代码

import cv2
from threading import Thread
import time
import numpy as np
from tkinter import Button, Label, mainloop, Tk, RIGHT

class GPIOControllersystem:
    def __init__(self,OutPinOne=22, OutPinTwo=27,Objsize=30,src=0):
        self.Objectsize = Objsize

        # Build GUI controller
        self.TK = Tk()                                                          # Place TK GUI class into self

        # Variables
        self.STSP = 0
        self.ShutdownVar = 0
        self.Abut = []
        self.Bbut = []
        self.Cbut = []
        self.Dbut = []

        # setup pi camera for aquisition
        self.resolution = (640,480)
        self.framerate = 60

        # Video capture parameters
        (w,h) = self.resolution
        self.bytesPerFrame = w * h

        self.Camera = cv2.VideoCapture(src)
        self.fgbg = cv2.createBackgroundSubtractorMOG2()

    def Testpins(self):
        while True:
            grabbed,frame = self.Camera.read()
            frame = self.fgbg.apply(frame)

            if self.ShutdownVar ==1:
                break
            if self.STSP == 1:
                pic1, pic2 = map(np.copy,(frame,frame))
                pic1[pic1 > 126] = 255
                pic2[pic2 <250] = 0
                frame = pic1
            elif self.STSP ==1:
                time.sleep(1)
            cv2.imshow("Window",frame)
        cv2.destroyAllWindows()

    def MProcessing(self):
        Thread(target=self.Testpins,args=()).start()
        return self

    def BuildGUI(self):
        self.Abut = Button(self.TK,text = "Start/Stop System",command = self.CallbackSTSP)
        self.Bbut = Button(self.TK,text = "Change Pump Speed",command = self.CallbackShutdown)
        self.Cbut = Button(self.TK,text = "Shutdown System",command = self.callbackPumpSpeed)
        self.Dbut = Button(self.TK,text = "Start System",command = self.MProcessing)

        self.Abut.pack(padx=5,pady=10,side=RIGHT)
        self.Bbut.pack(padx=5,pady=10,side=RIGHT)
        self.Cbut.pack(padx=5,pady=10,side=RIGHT)
        self.Dbut.pack(padx=5,pady=10,side=RIGHT)
        Label(self.TK, text="Controller").pack(padx=5, pady=10, side=RIGHT)
        mainloop()

    def CallbackSTSP(self):
        if self.STSP == 1:
            self.STSP = 0
            print("stop")
        elif self.STSP == 0:
            self.STSP = 1
            print("start")

    def CallbackShutdown(self):
        self.ShutdownVar = 1

    def callbackPumpSpeed(self):
        pass

if __name__ == "__main__":
    GPIOControllersystem().BuildGUI()

matplotlib.pyplot.imshow() ,我可以看到raspberry pi摄像头和opencv之间的连接是通过bcm2835-v4l2连接工作的。

更新:所以在测试时我发现当我执行以下任务时

import cv2
import matplotlib

camera = cv2.VideoCapture(0)
grab,frame = camera.read()
matplotlib.pyplot.imshow(frame)

grab,frame = camera.read()
matplotlib.pyplot.imshow(frame)