Question

这是我检测圆圈/球的代码。我想从Pi相机中检测出足球。（足球可以是任何颜色。）我遇到了一些PiCameraValueError问题。这段代码有什么问题。我正在使用Raspberry Pi 2，Python2和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

正如here所述，

PiCameraValueError是响应的第二个例外 KeyboardInterrupt异常。这很正常，不是错误（这更多是输出机制的通用性的结果 picamera），但很难在Python 2中检测和响应（通常的方法可能会抓住 PiCameraValueError以及您的主脚本运行的任何循环）。在Python 3下，exception chaining已实现，您可以可能会回顾一堆异常来找到 KeyboardInterrupt one。

您需要做的是清除捕获之间的流。 PiRGBArray文档介绍了使用truncate函数执行此操作。

以下是python face detection raspberry pi with picamera

的示例

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

PiCameraValueError：分辨率为1920x1080的缓冲区长度不正确

1 个答案: