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55 lines
1.9 KiB
55 lines
1.9 KiB
/* |
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This program is free software: you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation, either version 3 of the License, or |
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(at your option) any later version. |
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This program 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 |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program. If not, see <http://www.gnu.org/licenses/>. |
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*/ |
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// |
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/// @file Derivative.h |
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/// @brief A class to implement a derivative (slope) filter |
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/// See http://www.holoborodko.com/pavel/numerical-methods/numerical-derivative/smooth-low-noise-differentiators/ |
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#pragma once |
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#include "FilterClass.h" |
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#include "FilterWithBuffer.h" |
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// 1st parameter <T> is the type of data being filtered. |
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// 2nd parameter <FILTER_SIZE> is the number of elements in the filter |
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template <class T, uint8_t FILTER_SIZE> |
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class DerivativeFilter : public FilterWithBuffer<T,FILTER_SIZE> |
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{ |
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public: |
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// constructor |
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DerivativeFilter() : FilterWithBuffer<T,FILTER_SIZE>() { |
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}; |
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// update - Add a new raw value to the filter, but don't recalculate |
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void update(T sample, uint32_t timestamp); |
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// return the derivative value |
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float slope(void); |
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// reset - clear the filter |
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virtual void reset() override; |
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private: |
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bool _new_data; |
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float _last_slope; |
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// microsecond timestamps for samples. This is needed |
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// to cope with non-uniform time spacing of the data |
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uint32_t _timestamps[FILTER_SIZE]; |
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}; |
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typedef DerivativeFilter<float,5> DerivativeFilterFloat_Size5; |
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typedef DerivativeFilter<float,7> DerivativeFilterFloat_Size7; |
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typedef DerivativeFilter<float,9> DerivativeFilterFloat_Size9;
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