PiCamera cannot be initialized as a class member when the script is run from command prompt

问题:

on my Raspberry Pi, I encounter a strange behaviour regarding the use of the PiCamera module.

The following code runs smoothly when either started from IDLE (F5) or from the command prompt ($python test.py)

import picamera  if __name__ == "__main__":     camera=picamera.PiCamera()     camera.close() 

But when I put the camera object into a class the code will run only when started from IDLE (F5):

import picamera  class VF:     def __init__(self):         self.camera = picamera.PiCamera()      def __del__(self):         self.camera.close()   if __name__ == "__main__":     myvf = VF() 

When I start the above code from the command prompt, I get the following error message:

mmal: mmal_vc_component_enable: failed to enable component: ENOSPC

Traceback (most recent call last): File "test.py", line 14, in myvf = VF()

File "test.py", line 6, in init self.camera = picamera.PiCamera()

File "/usr/lib/python2.7/dist-packages/picamera/camera.py", line 379, in init camera_num, self.STEREO_MODES[stereo_mode], stereo_decimate)

File "/usr/lib/python2.7/dist-packages/picamera/camera.py", line 505, in _init_camera prefix="Camera component couldn't be enabled")

File "/usr/lib/python2.7/dist-packages/picamera/exc.py", line 133, in mmal_check raise PiCameraMMALError(status, prefix)

picamera.exc.PiCameraMMALError: Camera component couldn't be enabled: Out of resources (other than memory)

The camera module is working correct, I just stripped the code down to the least possible size. Does anybody know this problem, or a similar problem, and can probably provide a solution? The Python Version is 2.7 and the Raspberry Rasbiab-System is completely up to date. Thanks in advance.

回答1:

I struggled with this one for hours, and kept getting the "out of resources" error. I finally figured out that in my take-the-picture function, I needed to make sure I did it like this:

     camera = PiCamera()     (...camera settings here...)     camera.capture(myfileName)     camera.close() 

If I didn't do the close(), I'd get that error every time. So make sure that camera.close() is getting called right after the 'snap'. It solved the problem for me.

回答2:

Found out, that the camera-module is not properly shut down when the destructor is not explicitly called (had LED turned off, so didn't see this).

IDLE handles a running camera by somehow resetting it before the script starts, but not the python interpreter.

So everything is ok now when the destructor is called before the script ends.

文章来源: PiCamera cannot be initialized as a class member when the script is run from command prompt