Image acquisition package

The image_acquisition package is part of the Octave Forge project.

There is not release package yet but if you can get the source here [1]

Example session

Lines starting with $ are commands executed on the octave prompt.

Let's load the package and list available hardware

$ pkg load image-acquisition
$ imaqhwinfo
ans =

 scalar structure containing the fields:

   driver = uvcvideo
   card = UVC Camera (046d:0825)
   bus_info = usb-0000:00:16.2-2
   version = 3.2.51
   capabilities =  83886081
   device = /dev/video0

$ $ obj = videoinput("v4l2", "/dev/video0") obj = videoinput for v4l2

     device             = /dev/video0
     driver             = uvcvideo
     card               = UVC Camera (046d:0825)
     VideoInput         = 0
     VideoResolution    = 320 x 240 px
     VideoFrameInterval = 1/30 s (30.0 fps)

$ get(obj) ans = {

 [1,1] = SelectedSourceName
 [2,1] = DeviceCapabilities
 [3,1] = VideoInput
 [4,1] = VideoResolution
 [5,1] = VideoFrameInterval
 [6,1] = VideoFormat
 [7,1] = brightness
 [8,1] = contrast
 [9,1] = saturation
 [10,1] = white_balance_temperature_auto
 [11,1] = gain
 [12,1] = power_line_frequency
 [13,1] = white_balance_temperature
 [14,1] = sharpness
 [15,1] = backlight_compensation
 [16,1] = exposure_auto
 [17,1] = exposure_absolute
 [18,1] = exposure_auto_priority

} $ $ get(obj, "DeviceCapabilities") ans =

 scalar structure containing the fields:

   driver = uvcvideo
   card = UVC Camera (046d:0825)
   bus_info = usb-0000:00:16.2-2
   version = 3.2.51
   capabilities =  83886081

$ $ set(obj, "VideoResolution") ans =

   640    480
   160    120
   176    144
   320    176
   320    240
   352    288
   432    240
   544    288
   640    360
   752    416
   800    448
   800    600
   864    480
   960    544
   960    720
  1024    576
  1184    656
  1280    720
  1280    960

$ set(obj, "VideoResolution", [320 240]) $ $ get(obj, "brightness") ans = 100 $ set(obj, "brightness") ans =

 scalar structure containing the fields:

   min = 0
   max =  255
   step =  1
   default =  128

$ set(obj, "brightness", 100) $ $ preview(obj)

Using v4l2loopback for tests

If you don't have a v4l2 device but test the package you could create a loopback device:

modprobe v4l2loopback
gst-launch-0.10 videotestsrc ! v4l2sink device=/dev/video0

Reporting bugs

Please install v4l2-ctl (for example from Debian package v4l-utils), run the following commands and attach the output.

$ v4l2-ctl -w --list-devices
$ v4l2-ctl -w -D
$ v4l2-ctl -w -L
$ v4l2-ctl -w -n
$ v4l2-ctl -w --list-formats

Enable libv4l2 logging:

$ export LIBV4L2_LOG_FILENAME=libv4l2_debug.log

Start octave and execute your commands/scripts which show the problem.

Please include the whole octave session beginning with the start of octave. There might be some warnings like "warning: function xyz shadows a built-in function" at start.

Exit octave and add libv4l2_debug.log to your bug report

Consider running the included tests:

test @videoinput/videoinput
test @videoinput/get
test @videoinput/set
test @videoinput/getsnapshot