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111 lines
4.4 KiB
111 lines
4.4 KiB
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- |
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/* |
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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 AverageFilter.h |
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/// @brief A class to provide the average of a number of samples |
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#ifndef __AVERAGE_FILTER_H__ |
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#define __AVERAGE_FILTER_H__ |
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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 <U> is a larger data type used during summation to prevent overflows |
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// 3rd parameter <FILTER_SIZE> is the number of elements in the filter |
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template <class T, class U, uint8_t FILTER_SIZE> |
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class AverageFilter : public FilterWithBuffer<T,FILTER_SIZE> |
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{ |
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public: |
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// constructor |
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AverageFilter() : FilterWithBuffer<T,FILTER_SIZE>(), _num_samples(0) { |
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}; |
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// apply - Add a new raw value to the filter, retrieve the filtered result |
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virtual T apply(T sample); |
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// reset - clear the filter |
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virtual void reset(); |
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private: |
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uint8_t _num_samples; // the number of samples in the filter, maxes out at size of the filter |
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}; |
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// Typedef for convenience (1st argument is the data type, 2nd is a larger datatype to handle overflows, 3rd is buffer size) |
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typedef AverageFilter<int8_t,int16_t,2> AverageFilterInt8_Size2; |
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typedef AverageFilter<int8_t,int16_t,3> AverageFilterInt8_Size3; |
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typedef AverageFilter<int8_t,int16_t,4> AverageFilterInt8_Size4; |
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typedef AverageFilter<int8_t,int16_t,5> AverageFilterInt8_Size5; |
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typedef AverageFilter<uint8_t,uint16_t,2> AverageFilterUInt8_Size2; |
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typedef AverageFilter<uint8_t,uint16_t,3> AverageFilterUInt8_Size3; |
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typedef AverageFilter<uint8_t,uint16_t,4> AverageFilterUInt8_Size4; |
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typedef AverageFilter<uint8_t,uint16_t,5> AverageFilterUInt8_Size5; |
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typedef AverageFilter<int16_t,int32_t,2> AverageFilterInt16_Size2; |
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typedef AverageFilter<int16_t,int32_t,3> AverageFilterInt16_Size3; |
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typedef AverageFilter<int16_t,int32_t,4> AverageFilterInt16_Size4; |
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typedef AverageFilter<int16_t,int32_t,5> AverageFilterInt16_Size5; |
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typedef AverageFilter<uint16_t,uint32_t,2> AverageFilterUInt16_Size2; |
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typedef AverageFilter<uint16_t,uint32_t,3> AverageFilterUInt16_Size3; |
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typedef AverageFilter<uint16_t,uint32_t,4> AverageFilterUInt16_Size4; |
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typedef AverageFilter<uint16_t,uint32_t,5> AverageFilterUInt16_Size5; |
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typedef AverageFilter<int32_t,float,2> AverageFilterInt32_Size2; |
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typedef AverageFilter<int32_t,float,3> AverageFilterInt32_Size3; |
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typedef AverageFilter<int32_t,float,4> AverageFilterInt32_Size4; |
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typedef AverageFilter<int32_t,float,5> AverageFilterInt32_Size5; |
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typedef AverageFilter<uint32_t,float,2> AverageFilterUInt32_Size2; |
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typedef AverageFilter<uint32_t,float,3> AverageFilterUInt32_Size3; |
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typedef AverageFilter<uint32_t,float,4> AverageFilterUInt32_Size4; |
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typedef AverageFilter<uint32_t,float,5> AverageFilterUInt32_Size5; |
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typedef AverageFilter<float,float,5> AverageFilterFloat_Size5; |
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// Public Methods ////////////////////////////////////////////////////////////// |
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template <class T, class U, uint8_t FILTER_SIZE> |
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T AverageFilter<T,U,FILTER_SIZE>:: apply(T sample) |
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{ |
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U result = 0; |
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// call parent's apply function to get the sample into the array |
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FilterWithBuffer<T,FILTER_SIZE>::apply(sample); |
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// increment the number of samples so far |
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_num_samples++; |
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if( _num_samples > FILTER_SIZE || _num_samples == 0 ) |
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_num_samples = FILTER_SIZE; |
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// get sum of all values - there is a risk of overflow here that we ignore |
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for(uint8_t i=0; i<FILTER_SIZE; i++) |
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result += FilterWithBuffer<T,FILTER_SIZE>::samples[i]; |
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return (T)(result / _num_samples); |
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} |
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// reset - clear all samples |
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template <class T, class U, uint8_t FILTER_SIZE> |
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void AverageFilter<T,U,FILTER_SIZE>:: reset() |
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{ |
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// call parent's apply function to get the sample into the array |
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FilterWithBuffer<T,FILTER_SIZE>::reset(); |
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// clear our variable |
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_num_samples = 0; |
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} |
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#endif // __AVERAGE_FILTER_H__
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