opencv/modules/imgproc/doc/motion_analysis_and_object_tracking.rst
2011-04-24 21:02:14 +00:00

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Motion Analysis and Object Tracking
===================================
.. highlight:: cpp
.. index:: accumulate
accumulate
--------------
.. c:function:: void accumulate( const Mat\& src, Mat\& dst, const Mat\& mask=Mat() )
Adds an image to the accumulator.
:param src: Input image as 1- or 3-channel, 8-bit or 32-bit floating point.
:param dst: 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 statistics of a scene background viewed by a still camera and for the further foreground-background segmentation.
See Also:
:func:`accumulateSquare`,
:func:`accumulateProduct`,
:func:`accumulateWeighted`
.. index:: accumulateSquare
accumulateSquare
--------------------
.. c:function:: void accumulateSquare( const Mat\& src, Mat\& dst, const Mat\& mask=Mat() )
Adds the square of a source image to the accumulator.
:param src: Input image as 1- or 3-channel, 8-bit or 32-bit floating point.
:param dst: 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
accumulateProduct
---------------------
.. c:function:: 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
accumulateWeighted
----------------------
.. c:function:: void accumulateWeighted( const Mat\& src, Mat\& dst, double alpha, const Mat\& mask=Mat() )
Updates a running average.
:param src: Input image as 1- or 3-channel, 8-bit or 32-bit floating point.
:param dst: 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 a 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`