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。

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# 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()