How to use Aravis Python?

Using Aravis
1
  1. How to call these 2 functions?
camera.set_gain_auto()
camera.set_exposure_time_auto()

Both of these 2 functions require 2 parameters:

xception has occurred: TypeError
Aravis.Camera.set_gain_auto() takes exactly 2 arguments (1 given)
  File "....../arv-camera-test.py", line 34, in <module>
    camera.set_gain_auto()
  1. Why there is ALWAYS such an ERROR while writing into USB3Vision camera?
Exception has occurred: GError
arv-device-error-quark: USB3Vision write_memory error (access-denied) (5)
  File "....../arv-camera-test.py", line 31, in <module>
    camera.set_region (0,0,1440,1080)
  1. How to let Aravis automatically find multiple cameras?
    I mean camera2 = Aravis.Camera.new (None) ONLY finds the very FIRST camera, but NOT the other cameras.
2

For discovering multiple cameras:

Aravis.update_device_list()
devices = Aravis.get_n_devices()

4

I am working to create a higher level Python interface heavily utilizing Aravis. Please consider using, contributing to it here:

It is still very much a WIP, but the data-capture tool already allows quick and easy config and running of cameras via Python + Aravis and a JSON configuration file.

5

If you need a relatively compact example, check out __init__ in this module, which is used from the main script. It works for a single type of camera (VRMagic LineScan3D) but might be a useful inspiration.

For multiple cameras, construct the Camera instances with their respective serial number as done e.g. here (that is the code shown by arv-tool discovery).