Video camera
============

.. image:: ../../../media/sensors/video_camera.png
  :align: center
  :width: 600


**A camera capturing RGBA image**


This sensor emulates a single video camera. It generates a series of
RGBA images.  Images are encoded as binary char arrays, with 4 bytes
per pixel.

Camera calibration matrix
-------------------------

The camera configuration parameters implicitly define a geometric camera in
blender units. Knowing that the **cam_focal** attribute is a value that
represents the distance in Blender unit at which the largest image dimension is
32.0 Blender units, the camera intrinsic calibration matrix is defined as

+--------------+-------------+---------+
| **alpha_u**  |      0      | **u_0** |
+--------------+-------------+---------+
|       0      | **alpha_v** | **v_0** |
+--------------+-------------+---------+
|       0      |      0      |    1    |
+--------------+-------------+---------+

where:

- **alpha_u** == **alpha_v** = **cam_width** . **cam_focal** / 32 (we suppose
  here that **cam_width** > **cam_height**. If not, then use **cam_height** in
  the formula)
- **u_0** = **cam_width** / 2
- **v_0** = **cam_height** / 2

See also :doc:`../sensors/camera` for generic informations about Morse cameras.


.. cssclass:: properties morse-section

Configuration parameters for Video camera
-----------------------------------------


You can set these properties in your scripts with ``<component>.properties(<property1>=..., <property2>=...)``.

- ``cam_width`` (default: ``256``)
	(no documentation available yet)
- ``cam_height`` (default: ``256``)
	(no documentation available yet)
- ``cam_focal`` (default: ``25.0``)
	(no documentation available yet)
- ``cam_near`` (default: ``0.1``)
	(no documentation available yet)
- ``cam_far`` (default: ``100.0``)
	(no documentation available yet)
- ``Vertical_Flip`` (default: ``True``)
	(no documentation available yet)
- ``retrieve_depth`` (default: ``False``)
	(no documentation available yet)
- ``retrieve_zbuffer`` (default: ``False``)
	(no documentation available yet)


.. cssclass:: fields morse-section

Data fields
-----------


This sensor exports these datafields at each simulation step:

- ``timestamp`` (float, initial value: ``0.0``)
	number of seconds in simulated time
- ``image`` (buffer, initial value: ``none``)
	The data captured by the camera, stored as a Python Buffer             class  object. The data is of size ``(cam_width * cam_height * 4)``            bytes. The image is stored as RGBA.
- ``intrinsic_matrix`` (mat3<float>, initial value: ``none``)
	The intrinsic calibration matrix, stored as a 3x3 row major Matrix.

*Interface support:*

- :tag:`pocolibs`  as `ViamImageBank <http://trac.laas.fr/git/viam-genom/tree/viamStruct.h?h=viam-genom-1#n346>`_ (:py:mod:`morse.middleware.pocolibs.sensors.viam.ViamPoster`)
- :tag:`ros`  as `sensor_msgs/Image <http://ros.org/doc/api/sensor_msgs/html/msg/Image.html>`_ (:py:mod:`morse.middleware.ros.video_camera.VideoCameraPublisher`)
- :tag:`socket`  as base64 encoded RGBA image (:py:mod:`morse.middleware.sockets.video_camera.VideoCameraPublisher`)
- :tag:`yarp`  as yarp::ImageRGBA (:py:mod:`morse.middleware.yarp.video_camera.YarpImagePublisher`)


.. cssclass:: services morse-section

Services for Video camera
-------------------------

- ``get_properties()`` (blocking)
    Returns the properties of a component.
    
    
  - Return value

    a dictionary of the current component's properties  

- ``get_local_data()`` (blocking)
    Returns the current data stored in the sensor.
    
    
  - Return value

    a dictionary of the current sensor's data 

- ``set_property(prop_name, prop_val)`` (blocking)
    Modify one property on a component
    
    
  - Parameters

    - ``prop_name``: the name of the property to modify (as shown the documentation)
    - ``prop_val``: the new value of the property. Note that there is no checking about the type of the value so be careful

  - Return value

    nothing 

- ``capture(n)`` (non blocking)
    Capture **n** images
    
    
  - Parameters

    - ``n``: the number of images to take. A negative number means           take image indefinitely

- ``get_configurations()`` (blocking)
    Returns the configurations of a component (parsed from the properties).
    
    
  - Return value

    a dictionary of the current component's configurations  



.. cssclass:: examples morse-section

Examples
--------


The following examples show how to use this component in a *Builder* script:

.. code-block:: python


    from morse.builder import *
    
    # adds a default robot (the MORSE mascott!)
    robot = Morsy()
    
    # creates a new instance of the sensor
    videocamera = VideoCamera()

    # place your component at the correct location
    videocamera.translate(<x>, <y>, <z>)
    videocamera.rotate(<rx>, <ry>, <rz>)
    
    robot.append(videocamera)
    
    # define one or several communication interface, like 'socket'
    videocamera.add_interface(<interface>)

    env = Environment('empty')
    

.. cssclass:: files morse-section

Other sources of examples
+++++++++++++++++++++++++

- `Source code <../../_modules/morse/sensors/video_camera.html>`_
- `Unit-test <../../_modules/base/video_camera_testing.html>`_




*(This page has been auto-generated from MORSE module morse.sensors.video_camera.)*