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91 lines
3.8 KiB
C
91 lines
3.8 KiB
C
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////////////////////////////////////////////////////////////////////////////////
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///
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/// The routine detects highest value on an array of values and calculates the
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/// precise peak location as a mass-center of the 'hump' around the peak value.
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///
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/// Author : Copyright (c) Olli Parviainen
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/// Author e-mail : oparviai 'at' iki.fi
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/// SoundTouch WWW: http://www.surina.net/soundtouch
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///
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////////////////////////////////////////////////////////////////////////////////
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//
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// License :
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//
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// SoundTouch audio processing library
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// Copyright (c) Olli Parviainen
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2.1 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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//
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////////////////////////////////////////////////////////////////////////////////
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#ifndef _PeakFinder_H_
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#define _PeakFinder_H_
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namespace soundtouch
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{
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class PeakFinder
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{
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protected:
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/// Min, max allowed peak positions within the data vector
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int minPos, maxPos;
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/// Calculates the mass center between given vector items.
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double calcMassCenter(const float *data, ///< Data vector.
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int firstPos, ///< Index of first vector item belonging to the peak.
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int lastPos ///< Index of last vector item belonging to the peak.
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) const;
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/// Finds the data vector index where the monotoniously decreasing signal crosses the
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/// given level.
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int findCrossingLevel(const float *data, ///< Data vector.
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float level, ///< Goal crossing level.
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int peakpos, ///< Peak position index within the data vector.
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int direction /// Direction where to proceed from the peak: 1 = right, -1 = left.
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) const;
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// Finds real 'top' of a peak hump from neighnourhood of the given 'peakpos'.
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int findTop(const float *data, int peakpos) const;
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/// Finds the 'ground' level, i.e. smallest level between two neighbouring peaks, to right-
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/// or left-hand side of the given peak position.
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int findGround(const float *data, /// Data vector.
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int peakpos, /// Peak position index within the data vector.
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int direction /// Direction where to proceed from the peak: 1 = right, -1 = left.
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) const;
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/// get exact center of peak near given position by calculating local mass of center
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double getPeakCenter(const float *data, int peakpos) const;
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public:
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/// Constructor.
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PeakFinder();
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/// Detect exact peak position of the data vector by finding the largest peak 'hump'
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/// and calculating the mass-center location of the peak hump.
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///
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/// \return The location of the largest base harmonic peak hump.
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double detectPeak(const float *data, /// Data vector to be analyzed. The data vector has
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/// to be at least 'maxPos' items long.
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int minPos, ///< Min allowed peak location within the vector data.
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int maxPos ///< Max allowed peak location within the vector data.
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);
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};
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}
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#endif // _PeakFinder_H_
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