PiCameraValueError: неправильная длина буфера для разрешения 1920x1080

Question

Это мой код для определения круга/шаров. Я хочу обнаружить футбольный мяч с камеры Pi. (футбольный мяч может быть любого цвета.) У меня возникают проблемы с некоторыми PiCameraValueError. Что не так с этим кодом. Я использую Raspberry Pi 2, Python2 и OpenCV.

from picamera.array import PiRGBArray 
from picamera import PiCamera 
import time 
import cv2 
import sys 
import imutils 
import cv2.cv as cv 
# initialize the camera and grab a reference to the raw camera capture 
camera = PiCamera() 

rawCapture = PiRGBArray(camera) 

# capture frames from the camera 
for frame in camera.capture_continuous(rawCapture, format="bgr"): 
    # grab the raw NumPy array representing the image, then initialize the timestamp 
    # and occupied/unoccupied text 
    image = frame.array 
    img = cv2.medianBlur(image, 5) 
    imgg = cv2.cvtColor(img, cv2.COLOR_RGB2GRAY) 
    cimg = cv2.cvtColor(imgg, cv2.COLOR_GRAY2BGR) 
    imgg = cv2.blur(imgg, (3,3)) 
      #imgg = cv2.dilate(imgg, np.ones((5, 5))) 
      #imgg = cv2.GaussianBlur(imgg,(5,5),0) 
    circles = cv2.HoughCircles(imgg, cv.CV_HOUGH_GRADIENT, 1, 20, param1=100, param2=40, minRadius=5, maxRadius=90) 
    cv2.imshow("cimg", imgg) 
    key = cv2.waitKey(1) 
    if key & 0xFF == ord('q'): 
     break 
    if circles is None: 
     continue 

    print circles 
      #circles = np.uint16(np.around(circles)) 
    for i in circles[0,:]: 
     cv2.circle(cimg,(i[0],i[1]),i[2],(0,255,0),1) # draw the outer circle 
        #cv2.circle(cimg,(i[0],i[1]),2,(0,0,255),3) # draw the center of the circle 
     cv2.imshow("Filtered", cimg) 

cv2.destroyWindow("cimg") 
cv2.destroyAllWindows() 

Answer 1

Как пояснил here,

the PiCameraValueError is a secondary exception raised in response to the KeyboardInterrupt exception. This is quite normal and not a bug (it's more a consequence of how generic the output mechanism is in picamera), but it is difficult to detect and respond to in Python 2 (the usual method there would probably be to catch the PiCameraValueError as well in whatever loop your main script runs). Under Python 3, exception chaining is implemented so you could potentially look back through the stack of exceptions to find the KeyboardInterrupt one.

Что вам нужно сделать, это ясно, что поток между захватами. Окно PiRGBArray охватывает это с помощью функции усечения.

Вот пример из, python face detection raspberry pi with picamera

import io 
import time 
import picamera 
with picamera.PiCamera() as camera: 
    stream = io.BytesIO() 
    for foo in camera.capture_continuous(stream, format='jpeg'): 
    # YOURS: for frame in camera.capture_continuous(stream, format="bgr", use_video_port=True): 
     # Truncate the stream to the current position (in case 
     # prior iterations output a longer image) 
     stream.truncate() 
     stream.seek(0) 
     if process(stream): 
      break