[RPi] picamera + OpenCV

之前試 picamera 不知道怎麼接到 OpenCV, 剛剛看了這篇, 學習了

不廢話直接看兩支程式吧 (imutils_camera.py)

#!/usr/bin/python

from imutils.video import VideoStream
import imutils
import time
import cv2 

vs = VideoStream(usePiCamera=1).start()
time.sleep(1)
width  = int(640)
height = int(480)

while True:
    start = time.time()

    # picamera videostream read
    frame = vs.read()
    frame = imutils.resize(frame, width=width)
    cv2.imshow("preview", frame)

    end = time.time()
    seconds = end - start
    print "time : {0} sec".format(round(seconds, 3)) 
    fps  = 1 / seconds;
    print "fps : {0}".format(round(fps, 3));

    if cv2.waitKey(1) & 0xFF == ord("q"):
        break

cv2.destroyAllWindows()

使用前要先 sudo pip install imutils


另外是使用 V4L2, 程式碼(v4l2_camera.py)

#!/usr/bin/python

import cv2 
import time

cap = cv2.VideoCapture(0)
cap.set(cv2.cv.CV_CAP_PROP_FRAME_WIDTH,  640)
cap.set(cv2.cv.CV_CAP_PROP_FRAME_HEIGHT, 480)

while True:
    start = time.time()

    # v4l2 read
    ret, frame = cap.read()
    cv2.imshow("preview", frame)

    end = time.time()
    seconds = end - start
    print "time : {0} sec".format(round(seconds, 3)) 
    fps  = 1 / seconds;
    print "fps : {0}".format(round(fps, 3));

    if cv2.waitKey(1) & 0xFF == ord("q"):
        break

cap.release()
cv2.destroyAllWindows()

使用前要先 sudo modprobe bcm2835-v4l2

這樣寫看起來是使用 picamera 反而比較慢, 如果用原型的話就可以看出還是 V4L2 比較慢

import picamera
from picamera.array import PiRGBArray
import time
import cv2 

time.sleep(1)
resolution = (640, 480)

with picamera.PiCamera() as camera:
    camera.resolution = resolution
    rawCapture = PiRGBArray(camera, size=resolution)
    stream = camera.capture_continuous(rawCapture, format="bgr", use_video_port=True)
        
    for f in stream:
        start = time.time()

        frame = f.array
        rawCapture.truncate(0)
        cv2.imshow("preview", frame)

        end = time.time()
        seconds = end - start
        print "time : {0} sec".format(round(seconds, 3)) 
        fps  = 1 / seconds;
        print "fps : {0}".format(round(fps, 3));

        if cv2.waitKey(1) & 0xFF == ord("q"):
            break