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Visual Servoing Platform
version 3.3.0
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#include <vpV4l2Grabber.h>
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, const vpRect &roi) |
void | acquire (vpImage< unsigned char > &I, struct timeval ×tamp, const vpRect &roi=vpRect()) |
void | acquire (vpImage< vpRGBa > &I) |
void | acquire (vpImage< vpRGBa > &I, const vpRect &roi) |
void | acquire (vpImage< vpRGBa > &I, struct timeval ×tamp, const vpRect &roi=vpRect()) |
bool | getField () |
vpV4l2FramerateType | getFramerate () |
vpV4l2PixelFormatType | getPixelFormat () |
vpV4l2Grabber & | operator>> (vpImage< unsigned char > &I) |
vpV4l2Grabber & | operator>> (vpImage< vpRGBa > &I) |
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 () |
Inherited functionalities from vpFramegrabber | |
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 |
Class that is a wrapper over the Video4Linux2 (V4L2) driver.
Thus to be enabled, this class needs the optional V4L2 3rd party. Installation instruction are provided here https://visp.inria.fr/3rd_v4l2.
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, Logitech QuickCam IM (V-USB39), 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
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 :
This first example available in tutorial-grabber-v4l2.cpp shows how to grab and display images from an usb camera.
This other example shows how to use this grabber with an analogic camera attached to a bttv PCI card.
Definition at line 133 of file vpV4l2Grabber.h.
Frame format type for capture.
Enumerator | |
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V4L2_FRAME_FORMAT | a field only |
V4L2_IMAGE_FORMAT | an interlaced image |
Definition at line 156 of file vpV4l2Grabber.h.
Frame rate type for capture.
Enumerator | |
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framerate_50fps | 50 frames per second |
framerate_25fps | 25 frames per second |
Definition at line 148 of file vpV4l2Grabber.h.
Pixel format type for capture.
Enumerator | |
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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 |
Definition at line 164 of file vpV4l2Grabber.h.
vpV4l2Grabber::vpV4l2Grabber | ( | ) |
Default constructor.
Setup the Video For Linux Two (V4L2) driver in streaming mode.
Default settings are:
\code 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 \endcode
The grabber allows also to grab a portion of an image using a region of interest. The following example shows how to grab a 320x240 region located on the top/left corner of the image that has a higher resolution (ie 640x480).
Definition at line 148 of file vpV4l2Grabber.cpp.
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explicit |
Default constructor.
Setup the Video For Linux Two (V4L2) driver in streaming mode.
verbose | : If true activates the verbose mode. |
Default settings are:
Definition at line 204 of file vpV4l2Grabber.cpp.
vpV4l2Grabber::vpV4l2Grabber | ( | unsigned | input, |
unsigned | scale = vpV4l2Grabber::DEFAULT_SCALE |
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Constructor.
Setup the Video For Linux Two (V4L2) driver in streaming mode.
input | : Video input port. |
scale | : Decimation factor. |
Default settings are:
Definition at line 250 of file vpV4l2Grabber.cpp.
vpV4l2Grabber::vpV4l2Grabber | ( | vpImage< unsigned char > & | I, |
unsigned | input, | ||
unsigned | scale = vpV4l2Grabber::DEFAULT_SCALE |
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Constructor.
Setup the Video For Linux Two (V4L2) driver in streaming mode.
I | : Image data structure (grey 8 bits image) |
input | : Video input port. |
scale | : Decimation factor. |
Default settings are:
Definition at line 296 of file vpV4l2Grabber.cpp.
vpV4l2Grabber::vpV4l2Grabber | ( | vpImage< vpRGBa > & | I, |
unsigned | input, | ||
unsigned | scale = vpV4l2Grabber::DEFAULT_SCALE |
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Constructor.
Setup the Video For Linux Two (V4L2) driver in streaming mode.
I | : Image data structure (Color RGB32 bits image) |
input | : Video input port. |
scale | : Decimation factor. |
Default settings are:
Definition at line 345 of file vpV4l2Grabber.cpp.
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virtual |
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virtual |
Acquire a grey level image.
I | : Image data structure (8 bits image) |
vpFrameGrabberException::initializationError | : Frame grabber not initialized. |
Implements vpFrameGrabber.
Definition at line 525 of file vpV4l2Grabber.cpp.
Acquire a grey level image.
I | : Image data structure (8 bits image) |
roi | : Region of interest to grab from the full resolution image. |
vpFrameGrabberException::initializationError | : Frame grabber not initialized. |
Definition at line 544 of file vpV4l2Grabber.cpp.
void vpV4l2Grabber::acquire | ( | vpImage< unsigned char > & | I, |
struct timeval & | timestamp, | ||
const vpRect & | roi = vpRect() |
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Acquire a grey level image.
I | : Image data structure (8 bits image). |
timestamp | : Timeval data structure providing the unix time at which the frame was captured in the ringbuffer. Warning: some v4l2 drivers do not return the time since 1970 (the one returned by gettimeofday() or vpTime) but rather a time that counts from the boot time (i.e. uptime). |
roi | : Region of interest to grab from the full resolution image. By default acquire the whole image. |
vpFrameGrabberException::initializationError | : Frame grabber not initialized. |
Definition at line 570 of file vpV4l2Grabber.cpp.
Acquire a color image.
I | : Image data structure (32 bits image) |
vpFrameGrabberException::initializationError | : Frame grabber not initialized. |
Implements vpFrameGrabber.
Definition at line 651 of file vpV4l2Grabber.cpp.
Acquire a color image.
I | : Image data structure (32 bits image) |
roi | : Region of interest to grab from the full resolution image. |
vpFrameGrabberException::initializationError | : Frame grabber not initialized. |
Definition at line 670 of file vpV4l2Grabber.cpp.
void vpV4l2Grabber::acquire | ( | vpImage< vpRGBa > & | I, |
struct timeval & | timestamp, | ||
const vpRect & | roi = vpRect() |
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Acquire a color image.
I | : Image data structure (32 bits image). |
timestamp | : Timeval data structure providing the unix time at which the frame was captured in the ringbuffer. Warning: some v4l2 drivers do not return the time since 1970 (the one returned by gettimeofday() or vpTime) but rather a time that counts from the boot time (i.e. uptime). |
roi | : Region of interest to grab from the full resolution image. By default acquire the whole image. |
vpFrameGrabberException::initializationError | : Frame grabber not initialized. |
Definition at line 696 of file vpV4l2Grabber.cpp.
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virtual |
Close the video device.
Implements vpFrameGrabber.
Definition at line 841 of file vpV4l2Grabber.cpp.
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.
vpFrameGrabberException::otherError | : Video device returns a bad frame field. |
Definition at line 790 of file vpV4l2Grabber.cpp.
vpV4l2Grabber::vpV4l2FramerateType vpV4l2Grabber::getFramerate | ( | ) |
Return the framerate of the acquisition.
Definition at line 836 of file vpV4l2Grabber.cpp.
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inlineinherited |
Return the number of rows in the image.
Definition at line 113 of file vpFrameGrabber.h.
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inline |
Get the pixel format used for capture.
Definition at line 238 of file vpV4l2Grabber.h.
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inlineinherited |
Return the number of columns in the image.
Definition at line 115 of file vpFrameGrabber.h.
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virtual |
Initialize image acquisition in grey format. Set the pixel format acquisition to vpV4l2Grabber::V4L2_GREY_FORMAT.
I | : Image data structure (8 bits image). Once the device is open, the image is resized to the current acquisition size. |
vpFrameGrabberException::settingError | : Wrong input channel. |
Implements vpFrameGrabber.
Definition at line 409 of file vpV4l2Grabber.cpp.
Initialize image acquisition in color RGB32 format. Set the pixel format acquisition to vpV4l2Grabber::V4L2_RGB32_FORMAT.
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.
vpV4l2Grabber & vpV4l2Grabber::operator>> | ( | vpImage< unsigned char > & | I | ) |
Operator that allows to capture a grey level image.
I | : The captured image. |
Definition at line 1454 of file vpV4l2Grabber.cpp.
vpV4l2Grabber & vpV4l2Grabber::operator>> | ( | vpImage< vpRGBa > & | I | ) |
Operator that allows to capture a grey level image.
I | : The captured image. |
Definition at line 1476 of file vpV4l2Grabber.cpp.
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inline |
Set the device name.
devname | : Device name (like /dev/video0). |
Definition at line 284 of file vpV4l2Grabber.h.
void vpV4l2Grabber::setFramerate | ( | vpV4l2Grabber::vpV4l2FramerateType | framerate | ) |
Set the frame format depending on the framerate acquisition.
framerate | : The framerate for the acquisition. |
Definition at line 817 of file vpV4l2Grabber.cpp.
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inline |
Set image height to acquire.
Definition at line 261 of file vpV4l2Grabber.h.
void vpV4l2Grabber::setInput | ( | unsigned | input = vpV4l2Grabber::DEFAULT_INPUT | ) |
Set the video input port on the board.
Definition at line 372 of file vpV4l2Grabber.cpp.
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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.
nbuffers | : Number of ring buffers. |
Definition at line 276 of file vpV4l2Grabber.h.
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inline |
Set the pixel format for capture.`If the specified pixel format is out of range, we set the V4L2_RGB24_FORMAT.
pixelformat | : Camera pixel format coding. |
Definition at line 293 of file vpV4l2Grabber.h.
void vpV4l2Grabber::setScale | ( | unsigned | scale = vpV4l2Grabber::DEFAULT_SCALE | ) |
Set the decimation factor applied to full resolution images (768x576).
vpFrameGrabberException::settingError | : Wrong scale (should be between 1 and 16). |
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().
Definition at line 386 of file vpV4l2Grabber.cpp.
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inline |
Activates the verbose mode to print additional information on stdout.
verbose | : If true activates the verbose mode. |
Definition at line 247 of file vpV4l2Grabber.h.
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inline |
Set image width to acquire.
Definition at line 256 of file vpV4l2Grabber.h.
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static |
Definition at line 136 of file vpV4l2Grabber.h.
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Definition at line 137 of file vpV4l2Grabber.h.
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static |
Definition at line 143 of file vpV4l2Grabber.h.
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protectedinherited |
Number of rows in the image.
Definition at line 106 of file vpFrameGrabber.h.
Referenced by vpDirectShowGrabber::getFormat().
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inherited |
Set to true if the frame grabber has been initialized.
Definition at line 103 of file vpFrameGrabber.h.
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static |
Definition at line 142 of file vpV4l2Grabber.h.
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Definition at line 141 of file vpV4l2Grabber.h.
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Definition at line 140 of file vpV4l2Grabber.h.
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Definition at line 138 of file vpV4l2Grabber.h.
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Definition at line 139 of file vpV4l2Grabber.h.
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protectedinherited |
Number of columns in the image.
Definition at line 107 of file vpFrameGrabber.h.
Referenced by vpDirectShowGrabber::getFormat().