added docs for GMG_GPU

This commit is contained in:
Vladislav Vinogradov 2012-08-09 13:28:28 +04:00
parent ace7e9d842
commit 77cae11a74
2 changed files with 116 additions and 7 deletions

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@ -649,6 +649,114 @@ Releases all inner buffer's memory.
gpu::GMG_GPU
------------
.. ocv:class:: gpu::GMG_GPU
Class used for background/foreground segmentation. ::
class GMG_GPU_GPU
{
public:
GMG_GPU();
void initialize(Size frameSize, float min = 0.0f, float max = 255.0f);
void operator ()(const GpuMat& frame, GpuMat& fgmask, float learningRate = -1.0f, Stream& stream = Stream::Null());
void release();
int maxFeatures;
float learningRate;
int numInitializationFrames;
int quantizationLevels;
float backgroundPrior;
float decisionThreshold;
int smoothingRadius;
...
};
The class discriminates between foreground and background pixels by building and maintaining a model of the background. Any pixel which does not fit this model is then deemed to be foreground. The class implements algorithm described in [GMG2012]_.
Here are important members of the class that control the algorithm, which you can set after constructing the class instance:
.. ocv:member:: int maxFeatures
Total number of distinct colors to maintain in histogram.
.. ocv:member:: float learningRate
Set between 0.0 and 1.0, determines how quickly features are "forgotten" from histograms.
.. ocv:member:: int numInitializationFrames
Number of frames of video to use to initialize histograms.
.. ocv:member:: int quantizationLevels
Number of discrete levels in each channel to be used in histograms.
.. ocv:member:: float backgroundPrior
Prior probability that any given pixel is a background pixel. A sensitivity parameter.
.. ocv:member:: float decisionThreshold
Value above which pixel is determined to be FG.
.. ocv:member:: float smoothingRadius
Smoothing radius, in pixels, for cleaning up FG image.
gpu::GMG_GPU::GMG_GPU
---------------------
The default constructor.
.. ocv:function:: gpu::GMG_GPU::GMG_GPU()
Default constructor sets all parameters to default values.
gpu::GMG_GPU::initialize
------------------------
Initialize background model and allocates all inner buffers.
.. ocv:function:: void gpu::GMG_GPU::initialize(Size frameSize, float min = 0.0f, float max = 255.0f)
:param frameSize: Input frame size.
:param min: Minimum value taken on by pixels in image sequence. Usually 0.
:param max: Maximum value taken on by pixels in image sequence, e.g. 1.0 or 255.
gpu::GMG_GPU::operator()
------------------------
Updates the background model and returns the foreground mask
.. ocv:function:: void gpu::GMG_GPU::operator()(const GpuMat& frame, GpuMat& fgmask, Stream& stream = Stream::Null())
:param frame: Next video frame.
:param fgmask: The output foreground mask as an 8-bit binary image.
:param stream: Stream for the asynchronous version.
gpu::GMG_GPU::release
---------------------
Releases all inner buffer's memory.
.. ocv:function:: void gpu::GMG_GPU::release()
gpu::VideoWriter_GPU
---------------------
Video writer class.
@ -1093,3 +1201,4 @@ Parse next video frame. Implementation must call this method after new frame was
.. [MOG2004] Z. Zivkovic. *Improved adaptive Gausian mixture model for background subtraction*. International Conference Pattern Recognition, UK, August, 2004
.. [ShadowDetect2003] Prati, Mikic, Trivedi and Cucchiarra. *Detecting Moving Shadows...*. IEEE PAMI, 2003
.. [VIBE2011] O. Barnich and M. Van D Roogenbroeck. *ViBe: A universal background subtraction algorithm for video sequences*. IEEE Transactions on Image Processing, 20(6) :1709-1724, June 2011
.. [GMG2012] A. Godbehere, A. Matsukawa and K. Goldberg. *Visual Tracking of Human Visitors under Variable-Lighting Conditions for a Responsive Audio Art Installation*. American Control Conference, Montreal, June 2012

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@ -2160,25 +2160,25 @@ public:
void release();
//! Total number of distinct colors to maintain in histogram.
int maxFeatures;
int maxFeatures;
//! Set between 0.0 and 1.0, determines how quickly features are "forgotten" from histograms.
float learningRate;
float learningRate;
//! Number of frames of video to use to initialize histograms.
int numInitializationFrames;
int numInitializationFrames;
//! Number of discrete levels in each channel to be used in histograms.
int quantizationLevels;
int quantizationLevels;
//! Prior probability that any given pixel is a background pixel. A sensitivity parameter.
float backgroundPrior;
float backgroundPrior;
//! value above which pixel is determined to be FG.
float decisionThreshold;
float decisionThreshold;
//! smoothing radius, in pixels, for cleaning up FG image.
int smoothingRadius;
int smoothingRadius;
private:
float maxVal_, minVal_;