/**
 * \page BoxAlgorithm_TimeFrequencyMapDisplay Time-frequency map display
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Detailed description
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 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_Description|
A Time-Frequency (TF) map displays power spectra of signals over time, making it possible to track changes in amplitudes over a given time span. To that end, it
 uses a color scale to convert amplitudes to colors. This makes it possible to represent a single spectrum as a column of color-coded blocks. As time goes by, they
 are shifted to the left of the graph to make room for more recent spectra. There is one map per channel.

 Depending on the resolution of the map, a variable number of frequency bands are displayed per spectrum, or column of the map.
 If the number of frequency bands equals the height of the map for a given channel, each frequency band is one pixel high. Smaller maps won't be able to display all
 frequency bands, while in bigger maps, each frequency band will be allotted an area that is one pixel high or more.

 Since a TF map displays a series of power spectra, input data should be preprocessed by a Spectral Analysis box, as is the case with the Power Spectrum plugin.
 See \ref Doc_BoxAlgorithm_PowerSpectrumDisplay for an example, and \ref Doc_BoxAlgorithm_SpectralAnalysis for more information.

 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_Description|
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Inputs description
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 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_Inputs|
 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_Inputs|

 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_Input1|
Power spectrum of each channel to display.
 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_Input1|
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Settings description
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 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_Settings|
Online options include :

 - Bottom Ruler : this button toggles time values on/off.
 - Min/Max Frequency : the range of frequency bands that are drawn may be adjusted with these buttons.
 - Time Scale : this setting adjusts the time span displayed by the plugin.
 - Select Channels : clicking this button pops up a dialog that allows to show/hide some of the channels.
 - Attenuation : this setting allows to gradually adapt color thresholds. Valid values are in the [0,1] interval.

 \image html timefrequencymapdisplay_toolbar.png "Time Frequency Map toolbar."
 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_Settings|

 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_Setting1|
Size of time window to display.
 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_Setting1|

 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_Setting2|
Minimum frequency to display in time frequency maps.
 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_Setting2|

 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_Setting3|
Maximum frequency to display in time frequency maps.
 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_Setting3|
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Online visualization settings
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 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_OnlineVisualizationSettings|
 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_OnlineVisualizationSettings|
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Examples description
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 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_Examples|
Practical example :

 This example is based on the following scenario file : tutorials/visualization/sample_time_frequency_map

 To test this plugin, one can extend the \ref Doc_DataVisualization_2DVisualization_PowerSpectrum example by adding a Time-Frequency Map plugin. Since Sinus Oscillator
 signals are made up of sinusoidal signals with frequencies in the [0-50Hz] range, one should make sure the minimum and maximum displayed frequencies settings of the
 Power Spectrum and TF Map plugins match this range. Results should look like the following screenshot.

 A few remarks :
 	- For now, there is no frequency scale displayed to the left of the maps. Frequencies are mapped from bottom to top for each channel.

 	- TF maps don't change much over time, which is logical since power spectra displayed by the Power Spectrum box are pretty much constant themselves. This translates
 	into (almost uninterrupted) horizontal lines in the TF maps.

 	- Finally, one can notice two dominant frequency bands in the power spectrum of each channel, where they stand out as high amplitude peaks. These bands translate into
 	dark horizontal lines in the TF maps.

 \image html timefrequencymapdisplay_online.png "Power spectra and their "history" displayed over the last 10 seconds using the TF map plugin."

 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_Examples|

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Miscellaneous description
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 * |OVP_DocBegin_BoxAlgorithm_TimeFrequencyMapDisplay_Miscellaneous|
 * |OVP_DocEnd_BoxAlgorithm_TimeFrequencyMapDisplay_Miscellaneous|
 */
