Question

我编写了一个代码，该代码将最终捕获图片，并在达到一定时间后终止。但是一旦脚本结束（即在使用时间终止代码之后），几秒钟后我将如何自动重新运行？？

import cv2
import time
import numpy

capture = cv2.VideoCapture(0)
capture.set(3,640)
capture.set(4,480)
img_counter = 0
frame_set = []
start_time = time.time()

while(True):
    ret , frame = capture.read()
    gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
    frame_set.append(gray)
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
    end_time = time.time()
    elapsed = end_time - start_time
    img_name = "opencv_frame_{}.png".format(img_counter)
    cv2.imwrite(img_name,gray)
    print("{} written!".format(img_counter))
    img_counter +=1
    if elapsed > 1:
        break
capture.release()
cv2.destroyAllWindows()

此代码会将图像保存到文件夹中，并在几秒钟后终止。几分钟后如何设置自动重新运行代码以再次捕获更多图像？

谢谢。

Answer 1

如果您在Windows上，则可以在任务计划程序中添加int Number1 = 0; int Number12 = 0; // Do not forget to initialize the varaiables: string text = ""; string text2 = ""; // Create (and initialize by system tomer) Random once, use many Random rnd = new Random(); // Do not use goto, but loops (they are more readable: we have an infinite loop here) while (true) { int month = rnd.Next(1, 10); // (month = 8) is an assignment, not comparison which is (month == 8) // Let's use C/C++ language trick: comparing in reversed order: // (8 == month) and you can easily find out such errors if (8 == month) Number1++; else if (3 == month) Number12++; if (1 == Number1) { text = "*"; // you want to leave the infinite loop (your current code never stops) break; } } // Let's inspect the outcome Console.Write($"Number1 = {Number1}; Number12 = {Number12} Text = {text}");脚本，并给其运行时间described here：

但是，如果要在python文件中执行此操作，则有几种方法。

第一种方法：

锁定计时器，而不是.py退出循环。

类似的东西：

break

因此您的代码应为：

import time
starttime=time.time()
while True:
  print("tick every 3 seconds")
  time.sleep(3)

第二种方法：

使用Twisted, which is an event-driven networking engine written in Python.，

import cv2
import time
import numpy

capture = cv2.VideoCapture(0)
capture.set(3,640)
capture.set(4,480)
img_counter = 0
frame_set = []
start_time = time.time()

while(True):
ret , frame = capture.read()
gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
frame_set.append(gray)
cv2.imshow('frame',gray)
if cv2.waitKey(1) & 0xFF == ord('q'):
    break
end_time = time.time()
elapsed = end_time - start_time
img_name = "opencv_frame_{}.png".format(img_counter)
cv2.imwrite(img_name,gray)
print("{} written!".format(img_counter))
img_counter +=1
if elapsed > 1:            
   capture.release()
   cv2.destroyAllWindows()
   time.sleep(3)

在这种情况下，您不需要时间锁定：

from twisted.internet import task, reactor

timeout = 60.0 # Sixty seconds

def doWork():
    #do work here
    pass

l = task.LoopingCall(doWork)
l.start(timeout) # call every sixty seconds

reactor.run()

注意：由于您正在捕获图片，因此将终止脚本到达特定时间后，您需要同步from twisted.internet import task, reactor import cv2 import time import numpy capture = cv2.VideoCapture(0) capture.set(3,640) capture.set(4,480) img_counter = 0 frame_set = [] start_time = time.time() timeout = 60.0 # Sixty seconds def doWork(): while (True): ret, frame = capture.read() gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) frame_set.append(gray) cv2.imshow('frame', gray) if cv2.waitKey(1) & 0xFF == ord('q'): break end_time = time.time() elapsed = end_time - start_time img_name = "opencv_frame_{}.png".format(img_counter) cv2.imwrite(img_name, gray) print("{} written!".format(img_counter)) img_counter += 1 if elapsed > 1: break capture.release() cv2.destroyAllWindows()) l = task.LoopingCall(doWork) l.start(timeout) # call every sixty seconds reactor.run() 在这种情况下，请确保您有timeout的时间碰撞。即如果脚本正在捕获图片5分钟，则超时应大于该值。换句话说，运行嗯之后的脚本，假设是7分钟，而这需要5分钟捕获图片。

无休止地打开和关闭网络摄像头？

1 个答案: