class MotionDetector():
_hasIgnoredFirstImage = False
_snapShotter = None
_isDetecting = False
_imageAnalyzer = None
_previousPixelCounts = []
_previousSquaredDifference = []
numberOfImagesToAverage = 3
motionDetectorHandler = None
# PiCameraSnapShotter callbacks
def snapShotterFileNameForCapture(self):
fileName = datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')[:-3]
fileName = "%s.bmp" % fileName
return fileName
def snapShotterDidCaptureImage(self, snapShotter, imagePath):
# the first image is ignored, as it is very different form the second
# one, even when no change in the scene is present. (Maybe the PiCam
# still has to focus or adjust light settings).
if not self._hasIgnoredFirstImage:
self._hasIgnoredFirstImage = True
os.remove(imagePath)
return
if self._imageAnalyzer == None:
self._imageAnalyzer = ImageAnalyzer(initialImagePath = imagePath)
else:
analysisResult = self._imageAnalyzer.compareNextImage(
imagePath)
if analysisResult != None:
(differentPixelCount,
totalSquaredDifference,
totalNumberOfPixels) = analysisResult
self.analyzeNewImageResult(
differentPixelCount,
totalSquaredDifference)
os.remove(imagePath)
def analyzeNewImageResult(
self,
differentPixelCount,
totalSquaredDifference):
self._previousPixelCounts.append(differentPixelCount)
self._previousSquaredDifference.append(totalSquaredDifference)
if len(self._previousSquaredDifference) > self.numberOfImagesToAverage:
self._previousSquaredDifference.pop(0)
self._previousPixelCounts.pop(0)
if len(self._previousPixelCounts) == self.numberOfImagesToAverage:
pixelSum = sum(self._previousSquaredDifference)
pixelLength = len(self._previousSquaredDifference)
averagePixelDifference = pixelSum / float(pixelLength)
differenceSum = sum(self._previousPixelCounts)
differenceLength = len(self._previousPixelCounts)
averagePixelCount = differenceSum / float(differenceLength)
pixels = abs(differentPixelCount - averagePixelCount)
squaredDelta = None
if abs(averagePixelDifference) > 0:
squaredDelta = abs(totalSquaredDifference / averagePixelDifference)
# these are some of the values that can be tweaked for
# a better detection experience (maybe a true)
if squaredDelta > 1.1 and pixels > 10:
if self.motionDetectorHandler is None:
timestamp = datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S.%f')[:-3]
print "%s - Motion detected, but there is no handler." %timestamp
else:
self.motionDetectorHandler.motionDetectorDetectedMotion(self)
def startDetecting(self):
if self._isDetecting == False:
self._isDetecting = True
thread = Thread(target = self._startDetectingOnThread)
thread.start()
else:
print "Already detecting, ignoring call to startDetecting()"
def _startDetectingOnThread(self):
if self._snapShotter == None:
snapShotter = PiCameraSnapshotter(repeats = True, interval = 1.0)
snapShotter.delegate = self
snapShotter.startSnapShotting()
while self._isDetecting == True:
time.sleep(1)
snapShotter.stopSnapShotting()
def stopDetecting(self):
if self._isDetecting == True:
self._imageAnalyzer.cancel();
self._isDetecting = False
else:
print "Not detecting, ignoring call to stopDetecting()"
