opencv/modules/imgproc/doc/motion_analysis_and_object_tracking.rst

Motion Analysis and Object Tracking
===================================

.. highlight:: cpp



.. index:: accumulate


cv::accumulate
--------------

`id=0.681079907994 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/imgproc/accumulate>`__




.. cfunction:: void accumulate( const Mat\& src, Mat\& dst, const Mat\& mask=Mat() )

    Adds image to the accumulator.





    
    :param src: The input image, 1- or 3-channel, 8-bit or 32-bit floating point 
    
    
    :param dst: The accumulator image with the same number of channels as input image, 32-bit or 64-bit floating-point 
    
    
    :param mask: Optional operation mask 
    
    
    
The function adds 
``src``
, or some of its elements, to 
``dst``
:



.. math::

    \texttt{dst} (x,y)  \leftarrow \texttt{dst} (x,y) +  \texttt{src} (x,y)  \quad \text{if} \quad \texttt{mask} (x,y)  \ne 0  


The function supports multi-channel images; each channel is processed independently.

The functions 
``accumulate*``
can be used, for example, to collect statistic of background of a scene, viewed by a still camera, for the further foreground-background segmentation.

See also: 
:func:`accumulateSquare`
, 
:func:`accumulateProduct`
, 
:func:`accumulateWeighted`

.. index:: accumulateSquare


cv::accumulateSquare
--------------------

`id=0.655955936814 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/imgproc/accumulateSquare>`__




.. cfunction:: void accumulateSquare( const Mat\& src, Mat\& dst,  const Mat\& mask=Mat() )

    Adds the square of the source image to the accumulator.





    
    :param src: The input image, 1- or 3-channel, 8-bit or 32-bit floating point 
    
    
    :param dst: The accumulator image with the same number of channels as input image, 32-bit or 64-bit floating-point 
    
    
    :param mask: Optional operation mask 
    
    
    
The function adds the input image 
``src``
or its selected region, raised to power 2, to the accumulator 
``dst``
:



.. math::

    \texttt{dst} (x,y)  \leftarrow \texttt{dst} (x,y) +  \texttt{src} (x,y)^2  \quad \text{if} \quad \texttt{mask} (x,y)  \ne 0  


The function supports multi-channel images; each channel is processed independently.

See also: 
:func:`accumulateSquare`
, 
:func:`accumulateProduct`
, 
:func:`accumulateWeighted`

.. index:: accumulateProduct


cv::accumulateProduct
---------------------

`id=0.866927763669 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/imgproc/accumulateProduct>`__




.. cfunction:: void accumulateProduct( const Mat\& src1, const Mat\& src2,                        Mat\& dst, const Mat\& mask=Mat() )

    Adds the per-element product of two input images to the accumulator.





    
    :param src1: The first input image, 1- or 3-channel, 8-bit or 32-bit floating point 
    
    
    :param src2: The second input image of the same type and the same size as  ``src1`` 
    
    
    :param dst: Accumulator with the same number of channels as input images, 32-bit or 64-bit floating-point 
    
    
    :param mask: Optional operation mask 
    
    
    
The function adds the product of 2 images or their selected regions to the accumulator 
``dst``
:



.. math::

    \texttt{dst} (x,y)  \leftarrow \texttt{dst} (x,y) +  \texttt{src1} (x,y)  \cdot \texttt{src2} (x,y)  \quad \text{if} \quad \texttt{mask} (x,y)  \ne 0  


The function supports multi-channel images; each channel is processed independently.

See also: 
:func:`accumulate`
, 
:func:`accumulateSquare`
, 
:func:`accumulateWeighted`

.. index:: accumulateWeighted


cv::accumulateWeighted
----------------------

`id=0.956120320296 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/cpp/imgproc/accumulateWeighted>`__




.. cfunction:: void accumulateWeighted( const Mat\& src, Mat\& dst,                         double alpha, const Mat\& mask=Mat() )

    Updates the running average.





    
    :param src: The input image, 1- or 3-channel, 8-bit or 32-bit floating point 
    
    
    :param dst: The accumulator image with the same number of channels as input image, 32-bit or 64-bit floating-point 
    
    
    :param alpha: Weight of the input image 
    
    
    :param mask: Optional operation mask 
    
    
    
The function calculates the weighted sum of the input image
``src``
and the accumulator 
``dst``
so that 
``dst``
becomes a running average of frame sequence:



.. math::

    \texttt{dst} (x,y)  \leftarrow (1- \texttt{alpha} )  \cdot \texttt{dst} (x,y) +  \texttt{alpha} \cdot \texttt{src} (x,y)  \quad \text{if} \quad \texttt{mask} (x,y)  \ne 0  


that is, 
``alpha``
regulates the update speed (how fast the accumulator "forgets" about earlier images).
The function supports multi-channel images; each channel is processed independently.

See also: 
:func:`accumulate`
, 
:func:`accumulateSquare`
, 
:func:`accumulateProduct`