我有以下代码：
#!/usr/bin/python
import StringIO
import subprocess
import os
import time
from datetime import datetime
from PIL import Image
# Original code written by brainflakes and modified to exit
# image scanning for loop as soon as the sensitivity value is exceeded.
# this can speed taking of larger photo if motion detected early in scan
# Motion detection settings:
# need future changes to read values dynamically via command line parameter or xml file
# --------------------------
# Threshold - (how much a pixel has to change by to be marked as "changed")
# Sensitivity - (how many changed pixels before capturing an image) needs to be higher if noisy view
# ForceCapture - (whether to force an image to be captured every forceCaptureTime seconds)
# filepath - location of folder to save photos
# filenamePrefix - string that prefixes the file name for easier identification of files.
threshold = 10
sensitivity = 180
forceCapture = True
forceCaptureTime = 60 * 60 # Once an hour
filepath = "/home/pi/camera"
filenamePrefix = "capture"
# File photo size settings
saveWidth = 1280
saveHeight = 960
diskSpaceToReserve = 40 * 1024 * 1024 # Keep 40 mb free on disk
# Capture a small test image (for motion detection)
def captureTestImage():
command = "raspistill -w %s -h %s -t 500 -e bmp -o -" % (100, 75)
imageData = StringIO.StringIO()
imageData.write(subprocess.check_output(command, shell=True))
imageData.seek(0)
im = Image.open(imageData)
buffer = im.load()
imageData.close()
return im, buffer
# Save a full size image to disk
def saveImage(width, height, diskSpaceToReserve):
keepDiskSpaceFree(diskSpaceToReserve)
time = datetime.now()
filename = filepath + "/" + filenamePrefix + "-%04d%02d%02d-%02d%02d%02d.jpg" % ( time.year, time.month, time.day, time.hour, time.minute, time.second)
subprocess.call("raspistill -w 1296 -h 972 -t 1000 -e jpg -q 15 -o %s" % filename, shell=True)
print "Captured %s" % filename
# Keep free space above given level
def keepDiskSpaceFree(bytesToReserve):
if (getFreeSpace() < bytesToReserve):
for filename in sorted(os.listdir(filepath + "/")):
if filename.startswith(filenamePrefix) and filename.endswith(".jpg"):
os.remove(filepath + "/" + filename)
print "Deleted %s to avoid filling disk" % filename
if (getFreeSpace() > bytesToReserve):
return
# Get available disk space
def getFreeSpace():
st = os.statvfs(".")
du = st.f_bavail * st.f_frsize
return du
# Get first image
image1, buffer1 = captureTestImage()
# Reset last capture time
lastCapture = time.time()
# added this to give visual feedback of camera motion capture activity. Can be removed as required
os.system('clear')
print " Motion Detection Started"
print " ------------------------"
print "Pixel Threshold (How much) = " + str(threshold)
print "Sensitivity (changed Pixels) = " + str(sensitivity)
print "File Path for Image Save = " + filepath
print "---------- Motion Capture File Activity --------------"
while (True):
# Get comparison image
image2, buffer2 = captureTestImage()
# Count changed pixels
changedPixels = 0
for x in xrange(0, 100):
# Scan one line of image then check sensitivity for movement
for y in xrange(0, 75):
# Just check green channel as it's the highest quality channel
pixdiff = abs(buffer1[x,y][1] - buffer2[x,y][1])
if pixdiff > threshold:
changedPixels += 1
# Changed logic - If movement sensitivity exceeded then
# Save image and Exit before full image scan complete
if changedPixels > sensitivity:
lastCapture = time.time()
saveImage(saveWidth, saveHeight, diskSpaceToReserve)
break
continue
# Check force capture
if forceCapture:
if time.time() - lastCapture > forceCaptureTime:
changedPixels = sensitivity + 1
# Swap comparison buffers
image1 = image2
buffer1 = buffer2
此代码在检测到移动后拍摄照片，并一直这样做，直到我手动停止它为止。 （我应该提一下代码是用于Raspberry Pi计算机）
在Stackoverflow上我也有以下代码由Nathan Jhaveri提供：
import SocketServer
from BaseHTTPServer import BaseHTTPRequestHandler
def some_function():
print "some_function got called"
class MyHandler(BaseHTTPRequestHandler):
def do_GET(self):
if self.path == '/captureImage':
saveImage(saveWidth, saveHeight, diskSpaceToReserve)
self.send_response(200)
httpd = SocketServer.TCPServer(("", 8080), MyHandler)
httpd.serve_forever()
此代码运行一个执行
的简单服务器saveImage(saveWidth, saveHeight, diskSpaceToReserve)
在服务器上访问url / captureImage时起作用。我遇到了这个问题。由于这两段代码都是无限循环，因此它们不能并排运行。我认为我需要做一些多线程，但这是我以前从未在Python中尝试过的东西。如果有人能帮助我重回正轨，我将不胜感激。
答案 0 :(得分：0)
这不是一个小问题。最好的办法是完成一些python线程教程，例如：http://www.tutorialspoint.com/python/python_multithreading.htm（通过谷歌找到）
答案 1 :(得分：0)
尝试使用网络服务器，并在后台线程上运行它，以便调用“serve_forever（）”不会阻止主线程的“while True：”循环。用以下内容替换现有的httpd.serve_forever（）调用：
import threading
class WebThread(threading.Thread):
def run(self):
httpd = SocketServer.TCPServer(("", 8080), MyHandler)
httpd.serve_forever()
WebThread().start()
确保代码块在“while（True）：”循环之前运行，并且您应该同时运行webserver循环和主线程循环。
请记住，拥有多个线程可能会变得复杂。当两个线程同时访问同一个资源时会发生什么？正如Velox在另一个答案中提到的那样，了解线程的更多信息是值得的。
答案 2 :(得分：0)
我可以使用多线程来说明一个简单的例子。
from http.server import BaseHTTPRequestHandler, HTTPServer
import concurrent.futures
import logging
import time
hostName = "localhost"
serverPort = 5001
class MyServer(BaseHTTPRequestHandler):
def do_GET(self):
self.send_response(200)
self.send_header("Content-type", "text/html")
self.end_headers()
self.wfile.write(bytes("<html><head><title>python3 http server</title><body>", "utf-8"))
def serverThread():
webServer = HTTPServer((hostName, serverPort), MyServer)
logging.info("Server started http://%s:%s" % (hostName, serverPort))
try:
webServer.serve_forever()
except :
pass
webServer.server_close()
logging.info("Server stopped.")
def logThread():
while True:
time.sleep(2.0)
logging.info('hi from log thread')
if __name__ == "__main__":
logging.basicConfig(level=logging.INFO)
with concurrent.futures.ThreadPoolExecutor(max_workers=2) as executor:
# Run Server
executor.submit(serverThread)
# Run A Parallel Thread
executor.submit(logThread)
这里我们有两个线程：一个服务器和另一个并行线程，每 2 秒记录一行。
你必须在单独的函数中定义每个线程对应的代码，并提交到concurrent.futures线程池。
顺便说一句，我还没有研究过以这种方式运行服务器的效率。