PiCamの高速化

2017年7月20日 - 未分類

RaspberryPiのpicameraは、小さくて優秀ですが、読み込み速度があまり早くないなって思っていました。ふと、Therad化すれば、早くなるんじゃないかって考えて調べるとありました。

Therad化することで、カメラ画像の読込が３，４倍早くなります。使い方も簡単です。ほぼ、ストレスなく動くように見えます。

# import the necessary packages
from picamera.array import PiRGBArray
from picamera import PiCamera
from threading import Thread
import cv2
import time

class PiVideoStream:
	def __init__(self, resolution=(320, 240), framerate=32):
		# initialize the camera and stream
		self.camera = PiCamera()
		self.camera.resolution = resolution
		self.camera.framerate = framerate
		self.rawCapture = PiRGBArray(self.camera, size=resolution)
		self.stream = self.camera.capture_continuous(self.rawCapture, format="bgr", use_video_port=True)
		self.stopped=False

		# initialize the frame and the variable used to indicate
		# if the thread should be stopped
		self.frame = None
		self.stopped = False
		#self.camera.resolution = (640, 480)
		#self.camera.framerate = 32
		self.camera.sharpness = 0
		self.camera.contrast = 0
		self.camera.brightness = 50
		self.camera.saturation = 0
		self.camera.ISO = 0
		self.camera.video_stabilization = False
		self.camera.exposure_compensation = 0
		#self.camera.exposure_mode = 'off'
		self.camera.awb_mode = 'flash'
		self.camera.meter_mode = 'average'
		self.camera.image_effect = 'none'
		self.camera.color_effects = None
		self.camera.rotation = 0
		self.camera.hflip = True
		self.camera.vflip = True
		self.camera.crop = (0.0, 0.0, 1.0, 1.0)

	def start(self):
		# start the thread to read frames from the video stream
		Thread(target=self.update, args=()).start()
		return self

	def update(self):
		# keep looping infinitely until the thread is stopped
		for f in self.stream:
			# grab the frame from the stream and clear the stream in
			# preparation for the next frame
			self.frame = f.array
			self.rawCapture.truncate(0)

			# if the thread indicator variable is set, stop the thread
			# and resource camera resources
			if self.stopped:
				self.stream.close()
				self.rawCapture.close()
				self.camera.close()
				return

	def read(self):
		# return the frame most recently read
		return self.frame

	def stop(self):
		# indicate that the thread should be stopped
		self.stopped = True

	def seek(self):
		self.rawCapture.seek(-1,2)


vs = PiVideoStream((640,480),32).start()
time.sleep(2.0) 

def PiCamCapture():
        return vs.read()

def PiCamCaptureSeek():
        return vs.seek()

def PiCamCaptureStop():
        vs.stop()
	
if __name__ == '__main__':
	#
	cv2.namedWindow('Frame', cv2.WINDOW_NORMAL)
	while True:
        	frame = PiCamCapture()

        	# check to see if the frame should be displayed to our screen
                cv2.imshow("Frame", frame)
               	key = cv2.waitKey(1) & 0xFF
               	if key == 27:
                       	break


	# do a bit of cleanup
       	cv2.destroyAllWindows()
	PiCamCaptureStop()