#include <visp3/sensor/vpV4l2Grabber.h>

Inheritance diagram for vpV4l2Grabber:

Public Types
enum	vpV4l2FramerateType { framerate_50fps, framerate_25fps }

enum	vpV4l2FrameFormatType { V4L2_FRAME_FORMAT, V4L2_IMAGE_FORMAT }

enum	vpV4l2PixelFormatType { V4L2_GREY_FORMAT, V4L2_RGB24_FORMAT, V4L2_RGB32_FORMAT, V4L2_BGR24_FORMAT, V4L2_YUYV_FORMAT, V4L2_MAX_FORMAT }

Public Member Functions
	vpV4l2Grabber ()

	vpV4l2Grabber (bool verbose)

	vpV4l2Grabber (unsigned input, unsigned scale=vpV4l2Grabber::DEFAULT_SCALE)

	vpV4l2Grabber (vpImage< unsigned char > &I, unsigned input, unsigned scale=vpV4l2Grabber::DEFAULT_SCALE)

	vpV4l2Grabber (vpImage< vpRGBa > &I, unsigned input, unsigned scale=vpV4l2Grabber::DEFAULT_SCALE)

virtual	~vpV4l2Grabber ()

void	open (vpImage< unsigned char > &I)

void	open (vpImage< vpRGBa > &I)

void	acquire (vpImage< unsigned char > &I)

void	acquire (vpImage< unsigned char > &I, struct timeval &timestamp)

void	acquire (vpImage< vpRGBa > &I)

void	acquire (vpImage< vpRGBa > &I, struct timeval &timestamp)

bool	getField ()

vpV4l2FramerateType	getFramerate ()

vpV4l2PixelFormatType	getPixelFormat ()

void	setVerboseMode (bool verbose)

void	setFramerate (vpV4l2FramerateType framerate)

void	setInput (unsigned input=vpV4l2Grabber::DEFAULT_INPUT)

void	setWidth (unsigned w)

void	setHeight (unsigned h)

void	setScale (unsigned scale=vpV4l2Grabber::DEFAULT_SCALE)

void	setNBuffers (unsigned nbuffers)

void	setDevice (const std::string &devname)

void	setPixelFormat (vpV4l2PixelFormatType pixelformat)

void	close ()

unsigned int	getHeight () const

unsigned int	getWidth () const

Public Attributes
bool	init

Static Public Attributes
static const unsigned int	DEFAULT_INPUT = 2

static const unsigned int	DEFAULT_SCALE = 2

static const __u32	MAX_INPUTS = 16

static const __u32	MAX_NORM = 16

static const __u32	MAX_FORMAT = 32

static const unsigned int	MAX_CTRL = 32

static const unsigned int	MAX_BUFFERS = 32

static const unsigned int	FRAME_SIZE = 288

Protected Attributes
unsigned int	height

unsigned int	width

Detailed Description

Class for the Video4Linux2 video device.

Information about Video4Linux can be found on http://linuxtv.org/v4lwiki/index.php/Main_Page

This class was tested with a Pinnacle PCTV Studio/Rave board but also with the following webcams (Logitech QuickCam Vision Pro 9000, Logitech QuickCam Orbit AF, Dell latitude E6400 internal webcam).

If the grabbing fail with a webcam, it means probably that you don't have the read/write permission on the /dev/video%d device. You can set the right permissions by "sudo chmod a+rw /dev/video*".

If the grabbing fails when the camera is attached to a bttv PCI card, it means potentially that you have not configured the linux bttv kernel module according to your board.

For that, depending on your linux distribution check the card id in

/usr/share/doc/kernel-doc-2.4.20/video4linux/bttv/CARDLIST
or /usr/share/doc/kernel-doc-2.6.20/Documentation/video4linux/CARDLIST.bttv

For example, the card id of a Pinnacle PCTV Studio/Rave board is 39. Once this id is determined, you have to set the bttv driver with, by adding

  options bttv card=39

in one of theses files :

/etc/modules.conf
or /etc/modprobe.conf

This first example available in tutorial-grabber-v4l2.cpp shows how to grab and display images from an usb camera.

#include <visp3/sensor/vpV4l2Grabber.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/core/vpImage.h>
int main()
{
#ifdef VISP_HAVE_V4L2
  try {
    vpImage<unsigned char> I;
    vpV4l2Grabber g;
    g.open(I);
    std::cout << "Image size: " << I.getWidth() << " " << I.getHeight() << std::endl;
#ifdef VISP_HAVE_X11
    vpDisplayX d(I);
#else
    std::cout << "No image viewer is available..." << std::endl;
#endif
    while(1) {
      g.acquire(I);
      vpDisplay::display(I);
      vpDisplay::flush(I);
      if (vpDisplay::getClick(I, false)) break;
    }
  }
  catch(vpException e) {
    std::cout << "Catch an exception: " << e << std::endl;
  }
#endif
}

This other example shows how to use this grabber with an analogic camera attached to a bttv PCI card.

#include <visp3/core/vpConfig.h>
#include <visp3/core/vpImage.h>
#include <visp3/sensor/vpV4l2Grabber.h>
#include <visp3/io/vpImageIo.h>
int main()
{
#if defined(VISP_HAVE_V4L2)
  vpImage<unsigned char> I;
  vpV4l2Grabber g;
  g.setInput(2);    // Input 2 on the board
  g.setFramerate(vpV4l2Grabber::framerate_25fps); //  25 fps
  g.setWidth(768);  // Acquired images are 768 width
  g.setHeight(576); // Acquired images are 576 height
  g.setNBuffers(3); // 3 ring buffers to ensure real-time acquisition
  g.open(I);        // Open the grabber
  g.acquire(I);     // Acquire a 768x576 grey image
  vpImageIo::write(I, "image.pgm"); // Save the image on the disk
#endif
}

Author: Fabien Spindler (Fabie.nosp@m.n.Sp.nosp@m.indle.nosp@m.r@ir.nosp@m.isa.f.nosp@m.r), Irisa / Inria Rennes

See also: vpFrameGrabber

Examples:: grabV4l2.cpp, HelloWorldOgre.cpp, HelloWorldOgreAdvanced.cpp, manGrabV4l2.cpp, servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, servoPioneerPoint2DDepthWithoutVpServo.cpp, tutorial-barcode-detector-live.cpp, tutorial-blob-tracker-live-v4l2.cpp, tutorial-face-detector-live.cpp, tutorial-grabber-v4l2.cpp, tutorial-klt-tracker-live-v4l2.cpp, tutorial-me-ellipse-tracker.cpp, tutorial-me-line-tracker.cpp, and tutorial-video-recorder.cpp.

Definition at line 132 of file vpV4l2Grabber.h.

Member Enumeration Documentation

enum vpV4l2Grabber::vpV4l2FrameFormatType

Frame format type for capture.

Enumerator
V4L2_FRAME_FORMAT	a field only
V4L2_IMAGE_FORMAT	an interlaced image

Definition at line 156 of file vpV4l2Grabber.h.

enum vpV4l2Grabber::vpV4l2FramerateType

Frame rate type for capture.

Enumerator
framerate_50fps	50 frames per second
framerate_25fps	25 frames per second

Definition at line 147 of file vpV4l2Grabber.h.

enum vpV4l2Grabber::vpV4l2PixelFormatType

Pixel format type for capture.

Enumerator
V4L2_GREY_FORMAT	8 Greyscale
V4L2_RGB24_FORMAT	24 RGB-8-8-8
V4L2_RGB32_FORMAT	32 RGB-8-8-8-8
V4L2_BGR24_FORMAT	24 BGR-8-8-8
V4L2_YUYV_FORMAT	16 YUYV 4:2:2
V4L2_MAX_FORMAT

Examples:: grabV4l2.cpp.

Definition at line 165 of file vpV4l2Grabber.h.

Constructor & Destructor Documentation

vpV4l2Grabber::vpV4l2Grabber ( )

Default constructor.

Setup the Video For Linux Two (V4L2) driver in streaming mode.

Default settings are:

Device name: /dev/video0: To change it use setDevice()
Number of ring buffers: 3. To change this value use setNBuffers(). For non real-time applications the number of buffers should be set to 1. For real-time applications to reach 25 fps or 50 fps a good compromise is to set the number of buffers to 3.
Framerate acquisition: 25 fps. Use setFramerate() to set 25 fps or 50 fps. These framerates are reachable only if enought buffers are set.
Input board: vpV4l2Grabber::DEFAULT_INPUT. Video input port. Use setInput() to change it.
Image size acquisition: vpV4l2Grabber::DEFAULT_SCALE. Use either setScale() or setWidth() and setHeight to change it.

vpImage<unsigned char> I; // Grey level image
vpV4l2Grabber g;
g.setInput(2);    // Input 2 on the board
g.setWidth(768);  // Acquired images are 768 width
g.setHeight(576); // Acquired images are 576 height
g.setNBuffers(3); // 3 ring buffers to ensure real-time acquisition
g.open(I);        // Open the grabber
g.acquire(I);     // Acquire a 768x576 grey image

Definition at line 114 of file vpV4l2Grabber.cpp.

References DEFAULT_INPUT, DEFAULT_SCALE, framerate_25fps, vpFrameGrabber::init, setDevice(), setFramerate(), setInput(), setNBuffers(), setPixelFormat(), setScale(), and V4L2_YUYV_FORMAT.

vpV4l2Grabber::vpV4l2Grabber ( bool verbose )

Default constructor.

Setup the Video For Linux Two (V4L2) driver in streaming mode.

Parameters

verbose : If true activates the verbose mode.

Default settings are:

Device name: /dev/video0: To change it use setDevice()
Number of ring buffers: 3. To change this value use setNBuffers(). For non real-time applications the number of buffers should be set to 1. For real-time applications to reach 25 fps or 50 fps a good compromise is to set the number of buffers to 3.
Framerate acquisition: 25 fps. Use setFramerate() to set 25 fps or 50 fps. These framerates are reachable only if enought buffers are set.
Input board: vpV4l2Grabber::DEFAULT_INPUT. Video input port. Use setInput() to change it.
Image size acquisition: vpV4l2Grabber::DEFAULT_SCALE. Use either setScale() or setWidth() and setHeight to change it.

vpImage<unsigned char> I; // Grey level image
vpV4l2Grabber g(true); // Activates the verbose mode
g.setInput(2);    // Input 2 on the board
g.setWidth(768);  // Acquired images are 768 width
g.setHeight(576); // Acquired images are 576 height
g.setNBuffers(3); // 3 ring buffers to ensure real-time acquisition
g.open(I);        // Open the grabber
g.acquire(I);     // Acquire a 768x576 grey image

Definition at line 173 of file vpV4l2Grabber.cpp.

References DEFAULT_INPUT, DEFAULT_SCALE, framerate_25fps, vpFrameGrabber::init, setDevice(), setFramerate(), setInput(), setNBuffers(), setPixelFormat(), setScale(), and V4L2_YUYV_FORMAT.

vpV4l2Grabber::vpV4l2Grabber	(	unsigned	input,
		unsigned	scale = `vpV4l2Grabber::DEFAULT_SCALE`
	)

Constructor.

Setup the Video For Linux Two (V4L2) driver in streaming mode.

Parameters

input	: Video input port.
scale	: Decimation factor.

Default settings are:

Device name: /dev/video0: To change it use setDevice()
Number of ring buffers: 3. To change this value use setNBuffers(). For non real-time applications the number of buffers should be set to 1. For real-time applications to reach 25 fps or 50 fps a good compromise is to set the number of buffers to 3.
Framerate acquisition: 25 fps. Use setFramerate() to set 25 fps or 50 fps. These framerates are reachable only if enought buffers are set.

vpImage<unsigned char> I; // Grey level image
vpV4l2Grabber g(1, 2); // Select input 1, and half full size resolution images.
g.open(I);             // Open the grabber
g.acquire(I);          // Acquire a 384x288 grey image

Definition at line 223 of file vpV4l2Grabber.cpp.

References framerate_25fps, vpFrameGrabber::init, setDevice(), setFramerate(), setInput(), setNBuffers(), and setScale().

vpV4l2Grabber::vpV4l2Grabber	(	vpImage< unsigned char > &	I,
		unsigned	input,
		unsigned	scale = `vpV4l2Grabber::DEFAULT_SCALE`
	)

Constructor.

Setup the Video For Linux Two (V4L2) driver in streaming mode.

Parameters

I	: Image data structure (grey 8 bits image)
input	: Video input port.
scale	: Decimation factor.

Default settings are:

Device name: /dev/video0: To change it use setDevice()
Number of ring buffers: 3. To change this value use setNBuffers(). For non real-time applications the number of buffers should be set to 1. For real-time applications to reach 25 fps or 50 fps a good compromise is to set the number of buffers to 3.
Framerate acquisition: 25 fps. Use setFramerate() to set 25 fps or 50 fps. These framerates are reachable only if enought buffers are set.

vpImage<unsigned char> I; // Grey level image
vpV4l2Grabber g(I, 1, 2); // Select input 1, and half full size resolution
                          // images and open the grabber
g.acquire(I);             // Acquire a 384x288 grey image

Definition at line 272 of file vpV4l2Grabber.cpp.

References framerate_25fps, vpFrameGrabber::init, open(), setDevice(), setFramerate(), setInput(), setNBuffers(), and setScale().

vpV4l2Grabber::vpV4l2Grabber	(	vpImage< vpRGBa > &	I,
		unsigned	input,
		unsigned	scale = `vpV4l2Grabber::DEFAULT_SCALE`
	)

Constructor.

Setup the Video For Linux Two (V4L2) driver in streaming mode.

Parameters

I	: Image data structure (Color RGB32 bits image)
input	: Video input port.
scale	: Decimation factor.

Default settings are:

Device name: /dev/video0: To change it use setDevice()
Number of ring buffers: 3. To change this value use setNBuffers(). For non real-time applications the number of buffers should be set to 1. For real-time applications to reach 25 fps or 50 fps a good compromise is to set the number of buffers to 3.
Framerate acquisition: 25 fps. Use setFramerate() to set 25 fps or 50 fps. These framerates are reachable only if enought buffers are set.

vpImage<vpRGBa> I;        // Color image
vpV4l2Grabber g(I, 1, 2); // Select input 1, and half full size resolution
                          // images and open the grabber
g.acquire(I);             // Acquire a 384x288 color image

Definition at line 324 of file vpV4l2Grabber.cpp.

References framerate_25fps, vpFrameGrabber::init, open(), setDevice(), setFramerate(), setInput(), setNBuffers(), and setScale().

vpV4l2Grabber::~vpV4l2Grabber ( )

virtual

Destructor.

See also: close()

Definition at line 349 of file vpV4l2Grabber.cpp.

References close().

Member Function Documentation

void vpV4l2Grabber::acquire ( vpImage< unsigned char > & I )

virtual

Acquire a grey level image.

Parameters

I	: Image data structure (8 bits image)

Exceptions

vpFrameGrabberException::initializationError : Frame grabber not initialized.

See also: getField()

Implements vpFrameGrabber.

Examples:: grabV4l2.cpp, HelloWorldOgre.cpp, HelloWorldOgreAdvanced.cpp, manGrabV4l2.cpp, tutorial-barcode-detector-live.cpp, tutorial-face-detector-live.cpp, tutorial-grabber-v4l2.cpp, tutorial-klt-tracker-live-v4l2.cpp, and tutorial-video-recorder.cpp.

Definition at line 535 of file vpV4l2Grabber.cpp.

Referenced by acquire().

void vpV4l2Grabber::acquire	(	vpImage< unsigned char > &	I,
		struct timeval &	timestamp
	)

Acquire a grey level image.

Parameters

I	: Image data structure (8 bits image).
timestamp	: Timeval data structure providing the unix time at which the frame was captured in the ringbuffer.

Exceptions

vpFrameGrabberException::initializationError : Frame grabber not initialized.

See also: getField()

Definition at line 556 of file vpV4l2Grabber.cpp.

References vpImageConvert::BGRToGrey(), vpImage< Type >::bitmap, close(), vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpFrameGrabber::height, vpFrameGrabber::init, vpFrameGrabberException::initializationError, open(), vpImage< Type >::resize(), vpImageConvert::RGBaToGrey(), vpImageConvert::RGBToGrey(), V4L2_BGR24_FORMAT, V4L2_GREY_FORMAT, V4L2_RGB24_FORMAT, V4L2_RGB32_FORMAT, V4L2_YUYV_FORMAT, vpFrameGrabber::width, and vpImageConvert::YUYVToGrey().

void vpV4l2Grabber::acquire ( vpImage< vpRGBa > & I )

virtual

Acquire a color image.

Parameters

I	: Image data structure (32 bits image)

Exceptions

vpFrameGrabberException::initializationError : Frame grabber not initialized.

See also: getField()

Implements vpFrameGrabber.

Definition at line 616 of file vpV4l2Grabber.cpp.

References acquire().

void vpV4l2Grabber::acquire	(	vpImage< vpRGBa > &	I,
		struct timeval &	timestamp
	)

Acquire a color image.

Parameters

I	: Image data structure (32 bits image).
timestamp	: Timeval data structure providing the unix time at which the frame was captured in the ringbuffer.

Exceptions

vpFrameGrabberException::initializationError : Frame grabber not initialized.

See also: getField()

Definition at line 637 of file vpV4l2Grabber.cpp.

References vpImageConvert::BGRToRGBa(), vpImage< Type >::bitmap, close(), vpImage< Type >::getHeight(), vpImage< Type >::getWidth(), vpImageConvert::GreyToRGBa(), vpFrameGrabber::height, vpFrameGrabber::init, vpFrameGrabberException::initializationError, open(), vpImage< Type >::resize(), vpImageConvert::RGBToRGBa(), V4L2_BGR24_FORMAT, V4L2_GREY_FORMAT, V4L2_RGB24_FORMAT, V4L2_RGB32_FORMAT, V4L2_YUYV_FORMAT, vpFrameGrabber::width, and vpImageConvert::YUYVToRGBa().

void vpV4l2Grabber::close ( )

virtual

Close the video device.

Implements vpFrameGrabber.

Examples:: grabV4l2.cpp.

Definition at line 762 of file vpV4l2Grabber.cpp.

Referenced by acquire(), getField(), open(), setScale(), and ~vpV4l2Grabber().

bool vpV4l2Grabber::getField ( )

Return the field (odd or even) corresponding to the last acquired frame.

This method is to call after acquire() and has only a mean if the acquisition framerate is set to 50 fps.

Returns: Field of the acquired frame (0 if odd field, 1 if even field).

Exceptions

vpFrameGrabberException::otherError : Video device returns a bad frame field.

See also: acquire(), setFramerate()

Definition at line 704 of file vpV4l2Grabber.cpp.

References close(), and vpFrameGrabberException::otherError.

vpV4l2Grabber::vpV4l2FramerateType vpV4l2Grabber::getFramerate ( )

Return the framerate of the acquisition.

Returns: The actual framerate of the framegrabber.

See also: setFramerate()

Definition at line 752 of file vpV4l2Grabber.cpp.

unsigned int vpFrameGrabber::getHeight ( ) const

inlineinherited

Return the number of rows in the image.

Examples:: AROgre.cpp, and AROgreBasic.cpp.

Definition at line 113 of file vpFrameGrabber.h.

vpV4l2PixelFormatType vpV4l2Grabber::getPixelFormat ( )

inline

Get the pixel format used for capture.

Returns: Camera pixel format coding.

Definition at line 237 of file vpV4l2Grabber.h.

Referenced by open().

unsigned int vpFrameGrabber::getWidth ( ) const

inlineinherited

Return the number of columns in the image.

Examples:: AROgre.cpp, and AROgreBasic.cpp.

Definition at line 115 of file vpFrameGrabber.h.

void vpV4l2Grabber::open ( vpImage< unsigned char > & I )

virtual

Initialize image acquisition in grey format. Set the pixel format acquisition to vpV4l2Grabber::V4L2_GREY_FORMAT.

Parameters

I	: Image data structure (8 bits image). Once the device is open, the image is resized to the current acquisition size.

Exceptions

vpFrameGrabberException::settingError : Wrong input channel.

Implements vpFrameGrabber.

Examples:: grabV4l2.cpp, HelloWorldOgre.cpp, HelloWorldOgreAdvanced.cpp, manGrabV4l2.cpp, servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, servoPioneerPoint2DDepthWithoutVpServo.cpp, tutorial-blob-tracker-live-v4l2.cpp, tutorial-grabber-v4l2.cpp, tutorial-klt-tracker-live-v4l2.cpp, and tutorial-video-recorder.cpp.

Definition at line 402 of file vpV4l2Grabber.cpp.

References close(), getPixelFormat(), vpFrameGrabber::height, vpFrameGrabber::init, open(), vpImage< Type >::resize(), setPixelFormat(), vpFrameGrabberException::settingError, V4L2_MAX_FORMAT, and vpFrameGrabber::width.

Referenced by acquire(), open(), and vpV4l2Grabber().

void vpV4l2Grabber::open ( vpImage< vpRGBa > & I )

virtual

Initialize image acquisition in color RGB32 format. Set the pixel format acquisition to vpV4l2Grabber::V4L2_RGB32_FORMAT.

Parameters

I	: Image data structure (RGB32 bits image). Once the device is open, the image is resized to the current acquisition size.

Implements vpFrameGrabber.

Definition at line 470 of file vpV4l2Grabber.cpp.

References getPixelFormat(), vpFrameGrabber::height, vpFrameGrabber::init, open(), vpImage< Type >::resize(), setPixelFormat(), V4L2_MAX_FORMAT, and vpFrameGrabber::width.

void vpV4l2Grabber::setDevice ( const std::string & devname )

inline

Set the device name.

Parameters

devname : Device name (like /dev/video0).

Examples:: grabV4l2.cpp, servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, servoPioneerPoint2DDepthWithoutVpServo.cpp, tutorial-barcode-detector-live.cpp, tutorial-face-detector-live.cpp, tutorial-klt-tracker-live-v4l2.cpp, and tutorial-video-recorder.cpp.

Definition at line 293 of file vpV4l2Grabber.h.

Referenced by vpV4l2Grabber().

void vpV4l2Grabber::setFramerate ( vpV4l2Grabber::vpV4l2FramerateType framerate )

Set the frame format depending on the framerate acquisition.

Parameters

framerate

: The framerate for the acquisition.

If vpV4l2Grabber::framerate_25fps use vpV4l2Grabber::V4L2_IMAGE_FORMAT,
else if vpV4l2Grabber::framerate_50fps use vpV4l2Grabber::V4L2_FRAME_FORMAT.

Warning: If you want to acquire frames at 25 fps or 50 fps, you have to be aware of the number of buffers required for the streaming. A typical value could be 3 (see setNBuffers()).

See also: getFramerate(), setNBuffers()

Examples:: grabV4l2.cpp.

Definition at line 731 of file vpV4l2Grabber.cpp.

References framerate_25fps, V4L2_FRAME_FORMAT, and V4L2_IMAGE_FORMAT.

Referenced by vpV4l2Grabber().

void vpV4l2Grabber::setHeight ( unsigned h )

inline

Set image height to acquire.

Examples:: manGrabV4l2.cpp.

Definition at line 264 of file vpV4l2Grabber.h.

Referenced by setScale().

void vpV4l2Grabber::setInput ( unsigned input = vpV4l2Grabber::DEFAULT_INPUT )

Set the video input port on the board.

Examples:: grabV4l2.cpp, manGrabV4l2.cpp, servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, and servoPioneerPoint2DDepthWithoutVpServo.cpp.

Definition at line 358 of file vpV4l2Grabber.cpp.

Referenced by vpV4l2Grabber().

void vpV4l2Grabber::setNBuffers ( unsigned nbuffers )

inline

Set the number of buffers required for streaming data.

For non real-time applications the number of buffers should be set to 1. For real-time applications to reach 25 fps or 50 fps a good compromise is to set the number of buffers to 3.

Parameters

nbuffers : Number of ring buffers.

Examples:: manGrabV4l2.cpp.

Definition at line 282 of file vpV4l2Grabber.h.

Referenced by vpV4l2Grabber().

void vpV4l2Grabber::setPixelFormat ( vpV4l2PixelFormatType pixelformat )

inline

Set the pixel format for capture.`If the specified pixel format is out of range, we set the V4L2_RGB24_FORMAT.

Parameters

pixelformat : Camera pixel format coding.

Examples:: grabV4l2.cpp.

Definition at line 305 of file vpV4l2Grabber.h.

Referenced by open(), and vpV4l2Grabber().

void vpV4l2Grabber::setScale ( unsigned scale = vpV4l2Grabber::DEFAULT_SCALE )

Set the decimation factor applied to full resolution images (768x576).

Exceptions

vpFrameGrabberException::settingError : Wrong scale (should be between 1 and 16).

Parameters

scale : Decimation factor. If scale is set to 2, 384x288 images will be acquired.

An other way to specify the image size is to use setWidth() and setHeight().

Examples:: grabV4l2.cpp, servoPioneerPanSegment3D.cpp, servoPioneerPoint2DDepth.cpp, servoPioneerPoint2DDepthWithoutVpServo.cpp, tutorial-barcode-detector-live.cpp, and tutorial-face-detector-live.cpp.

Definition at line 376 of file vpV4l2Grabber.cpp.

References close(), setHeight(), vpFrameGrabberException::settingError, setWidth(), and vpERROR_TRACE.

Referenced by vpV4l2Grabber().

void vpV4l2Grabber::setVerboseMode ( bool verbose )

inline

Activates the verbose mode to print additional information on stdout.

Parameters

verbose : If true activates the verbose mode.

Examples:: grabV4l2.cpp.

Definition at line 245 of file vpV4l2Grabber.h.

void vpV4l2Grabber::setWidth ( unsigned w )

inline

Set image width to acquire.

Examples:: manGrabV4l2.cpp.

Definition at line 256 of file vpV4l2Grabber.h.

Referenced by setScale().

Member Data Documentation

const unsigned int vpV4l2Grabber::DEFAULT_INPUT = 2

static

Definition at line 135 of file vpV4l2Grabber.h.

Referenced by vpV4l2Grabber().

const unsigned int vpV4l2Grabber::DEFAULT_SCALE = 2

static

Definition at line 136 of file vpV4l2Grabber.h.

Referenced by vpV4l2Grabber().

const unsigned int vpV4l2Grabber::FRAME_SIZE = 288

static

Definition at line 142 of file vpV4l2Grabber.h.

unsigned int vpFrameGrabber::height

protectedinherited

Number of rows in the image.

Definition at line 107 of file vpFrameGrabber.h.

Referenced by vpDiskGrabber::acquire(), acquire(), vp1394TwoGrabber::acquire(), vp1394TwoGrabber::dequeue(), vp1394TwoGrabber::getHeight(), vpDiskGrabber::open(), open(), vp1394CMUGrabber::open(), vpVideoReader::open(), vp1394TwoGrabber::setFormat7ROI(), vp1394CMUGrabber::setVideoMode(), vp1394TwoGrabber::setVideoMode(), vp1394CMUGrabber::vp1394CMUGrabber(), and vp1394TwoGrabber::vp1394TwoGrabber().

bool vpFrameGrabber::init

inherited

Set to true if the frame grabber has been initialized.

Definition at line 105 of file vpFrameGrabber.h.

Referenced by acquire(), vp1394CMUGrabber::close(), vp1394TwoGrabber::close(), vpDiskGrabber::open(), open(), vp1394TwoGrabber::resetBus(), vp1394CMUGrabber::vp1394CMUGrabber(), vp1394TwoGrabber::vp1394TwoGrabber(), vpDiskGrabber::vpDiskGrabber(), and vpV4l2Grabber().

const unsigned int vpV4l2Grabber::MAX_BUFFERS = 32

static

Definition at line 141 of file vpV4l2Grabber.h.

const unsigned int vpV4l2Grabber::MAX_CTRL = 32

static

Definition at line 140 of file vpV4l2Grabber.h.

const __u32 vpV4l2Grabber::MAX_FORMAT = 32

static

Definition at line 139 of file vpV4l2Grabber.h.

const __u32 vpV4l2Grabber::MAX_INPUTS = 16

static

Definition at line 137 of file vpV4l2Grabber.h.

const __u32 vpV4l2Grabber::MAX_NORM = 16

static

Definition at line 138 of file vpV4l2Grabber.h.

unsigned int vpFrameGrabber::width

protectedinherited

Number of columns in the image.

Definition at line 108 of file vpFrameGrabber.h.

Referenced by vpDiskGrabber::acquire(), acquire(), vp1394TwoGrabber::acquire(), vp1394TwoGrabber::dequeue(), vp1394TwoGrabber::getWidth(), vpDiskGrabber::open(), open(), vp1394CMUGrabber::open(), vpVideoReader::open(), vp1394TwoGrabber::setFormat7ROI(), vp1394CMUGrabber::setVideoMode(), vp1394TwoGrabber::setVideoMode(), vp1394CMUGrabber::vp1394CMUGrabber(), and vp1394TwoGrabber::vp1394TwoGrabber().

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