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The {{Forge|image-acquisition}} package is part of the [[Octave Forge]] project.
The {{Forge|image_acquisition}} package is part of the [[Octave Forge]] project.


Build dependencies for Debian GNU/Linux are '''libv4l-dev''' and '''libfltk1.3-dev''' or '''libfltk1.1-dev'''. You can install it on GNU/Linux in octave with
There is not release package yet but if you can get the source here [http://sourceforge.net/p/octave/image-acquisition/ci/default/tree/]
  octave> pkg install -forge image-acquisition
 
If you see complains about a missing mkoctfile: [[FAQ#I_cannot_install_a_package._Octave_complains_about_a_missing_mkoctfile.]]
 
If you want to report a bug: [[Image_acquisition_package#Reporting_bugs]]
 
'''image-acquisition will not work on Windows as far as there is not port of v4l2 (standing for ''Video for Linux 2'')'''


== Example session ==
== Example session ==


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


=== Load the package and list available hardware ===
Let's load the package and list available hardware


  octave:> pkg load image-acquisition
<code>
  octave:> imaqhwinfo
  $ pkg load image-acquisition
  $ imaqhwinfo
  ans =
  ans =
   scalar structure containing the fields:
   scalar structure containing the fields:
     driver = uvcvideo
     driver = uvcvideo
     card = UVC Camera (046d:0825)
     card = UVC Camera (046d:0825)
     bus_info = usb-0000:00:12.2-4
     bus_info = usb-0000:00:16.2-2
     version = 3.16.7
     version = 3.2.51
     capabilities =   2.2314e+09
     capabilities = 83886081
     device = /dev/video0
     device = /dev/video0
 
</code>
=== Open the v4l2 device and output the result ===
$
 
$ obj = videoinput("v4l2", "/dev/video0")
octave:> obj = videoinput("v4l2", "/dev/video0")
obj = videoinput for v4l2
obj = videoinput for v4l2
       device             = /dev/video0
       device               = /dev/video0
       driver             = uvcvideo
       driver               = uvcvideo
       card               = UVC Camera (046d:0825)
       card                 = UVC Camera (046d:0825)
       VideoInput         = 0
       VideoInput           = 0
       VideoResolution   = 320 x 240 px
       VideoResolution     = 320 x 240 px
       VideoFrameInterval = 1/30 s (30.0 fps)
       VideoFormat          = YUYV
$ get(obj)
 
ans =  
=== Query which properties are available for the used device ===
{
 
The first 8 ones, starting with an upper letter are fixed, the other specific to the used v4l2 device.
octave:> get(obj)
ans =  
{
   [1,1] = SelectedSourceName
   [1,1] = SelectedSourceName
   [2,1] = ReturnedColorSpace
   [2,1] = DeviceCapabilities
   [3,1] = BayerSensorAlignment
   [3,1] = VideoInput
   [4,1] = DeviceCapabilities
   [4,1] = VideoResolution
   [5,1] = VideoInput
   [5,1] = VideoFrameInterval
   [6,1] = VideoResolution
   [6,1] = VideoFormat
   [7,1] = VideoFrameInterval
   [7,1] = brightness
   [8,1] = VideoFormat
   [8,1] = contrast
   [9,1] = brightness
   [9,1] = saturation
   [10,1] = contrast
   [10,1] = white_balance_temperature_auto
   [11,1] = saturation
   [11,1] = gain
   [12,1] = white_balance_temperature_auto
   [12,1] = power_line_frequency
   [13,1] = gain
   [13,1] = white_balance_temperature
   [14,1] = power_line_frequency
   [14,1] = sharpness
   [15,1] = white_balance_temperature
   [15,1] = backlight_compensation
   [16,1] = sharpness
   [16,1] = exposure_auto
   [17,1] = backlight_compensation
   [17,1] = exposure_absolute
   [18,1] = exposure_auto
   [18,1] = exposure_auto_priority
  [19,1] = exposure_absolute
}
  [20,1] = exposure_auto_priority
$
}
$ get(obj, "DeviceCapabilities")
ans =


=== Set VideoFormat to RGB3 aka RGB24 ===
  scalar structure containing the fields:


octave:> set(obj, "VideoFormat", "RGB3");
    driver = uvcvideo
    card = UVC Camera (046d:0825)
    bus_info = usb-0000:00:16.2-2
    version = 3.2.51
    capabilities =  83886081


=== List available video resolutions ===
$
$ set(obj, "VideoResolution")
ans =


octave:> set(obj, "VideoResolution")
ans =
     640    480
     640    480
     160    120
     160    120
Line 95: Line 90:
   1280    960
   1280    960


=== Set the video resolution to 320x240px ===
$ set(obj, "VideoResolution", [320 240])
$
$ get(obj, "brightness")
ans = 100
$ set(obj, "brightness")
ans =


octave:> set(obj, "VideoResolution", [320 240])
  scalar structure containing the fields:
 
=== Get the current brightness value ===
 
octave:> get(obj, "brightness")
ans =  100
 
=== Query possible range for brightness ===


octave:> set(obj, "brightness")
ans =
  scalar structure containing the fields:
     min = 0
     min = 0
     max =  255
     max =  255
Line 116: Line 104:
     default =  128
     default =  128


=== Set a new value for brightness ===
$ set(obj, "brightness", 100)
 
$
octave:> set(obj, "brightness", 100)
$ preview(obj)
 
=== Start preview ===
 
octave:> preview(obj)
 
Close it with CTRL+C or with [X] on the preview window
 
=== Use higher resolution and start streaming with 2 buffers ===
 
octave:> set(obj, "VideoResolution", [640 480]);
octave:> start(obj, 2)
 
=== Get an image from the buffers, view and save it ===
 
octave:> img = getsnapshot(obj);
octave:> image(img)
octave:> imwrite(img, "ex1_a.png")
octave:> [img, seq, t] = getsnapshot(obj);
octave:> seq
seq =  1
octave:> t
t =
  scalar structure containing the fields:
    tv_sec =  10281
    tv_usec =  779303
 
=== Stop streaming ===
 
octave:> stop(obj)


== Using v4l2loopback for tests ==
== Using v4l2loopback for tests ==
If you don't have a v4l2 device but want to test the package you could create a loopback device:
If you don't have a v4l2 device but test the package you could create a loopback device:
  modprobe v4l2loopback
  modprobe v4l2loopback
  gst-launch-0.10 videotestsrc ! v4l2sink device=/dev/video0
  gst-launch-0.10 videotestsrc ! v4l2sink device=/dev/video0
Line 176: Line 132:
There might be some warnings like "warning: function xyz shadows a built-in function" at start.
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. The logfile libv4l2_debug.log is overwritten between open/close so you have to rename it if you run different scripts.
Exit octave and add libv4l2_debug.log to your bug report


Consider running the included tests:
Consider running the included tests:


  octave> test @videoinput/videoinput
  test @videoinput/videoinput
  octave> test @videoinput/get
  test @videoinput/get
  octave> test @videoinput/set
  test @videoinput/set
  octave> test @videoinput/getsnapshot
  test @videoinput/getsnapshot
 
Run the compliance check (perhaps also with -s)
 
v4l2-compliance -d /dev/video0
 
== Build source from mercurial repository ==
 
'''Warning: You really should use the <pkg install -forge> method described above if you are not sure what you are doing here.'''
 
Get the source and build it yourself. The build dependencies for Debian GNU/Linux jessie are '''libv4l-dev''' and '''libfltk1.3-dev''' or '''libfltk1.1-dev'''. You also need the GNU autotools to generate the configure script.
 
$ hg clone http://hg.code.sf.net/p/octave/image-acquisition octave-image-acquisition
$ cd octave-image-acquisition/
$ make install
 
== make check ==
 
If you have cloned the hg repo you can also run the test scripts to see if all works.
 
$ cd octave-image-acquisition/devel
$ make check
octave -q run_tests.m
../src/__v4l2_handler__.cc........................ PASS 3/3
@videoinput/videoinput............................ PASS 1/1
@videoinput/get................................... PASS 4/4
@videoinput/set................................... PASS 7/7
@videoinput/getsnapshot........................... PASS 4/4
imaqhwinfo........................................ PASS 1/1
Summary:
  PASS  20
  FAIL  0
 
If there are tests which FAIL, then please have a look at the generated fntest.log and add it to your bug report.
 
[[Category:Octave Forge]]
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