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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
#include "maths/MedianFilter.h"
#include <cmath>
#include <cstdlib>
#define BOOST_TEST_DYN_LINK
#define BOOST_TEST_MAIN
#include <boost/test/unit_test.hpp>
BOOST_AUTO_TEST_SUITE(TestMedianFilter)
BOOST_AUTO_TEST_CASE(odd)
{
// A median filter of size N always retains a pool of N elements,
// which start out all-zero. So the output median will remain zero
// until N/2 elements have been pushed.
MedianFilter<double> f(3);
f.push(1); // 0 0 1
BOOST_CHECK_EQUAL(f.get(), 0);
BOOST_CHECK_EQUAL(f.get(), 0);
f.push(-3); // 0 1 -3
BOOST_CHECK_EQUAL(f.get(), 0);
f.push(5); // 1 -3 5
BOOST_CHECK_EQUAL(f.get(), 1);
f.push(7); // -3 5 7
BOOST_CHECK_EQUAL(f.get(), 5);
BOOST_CHECK_EQUAL(f.get(), 5);
f.push(3); // 5 7 3
BOOST_CHECK_EQUAL(f.get(), 5);
f.push(3); // 7 3 3
BOOST_CHECK_EQUAL(f.get(), 3);
}
BOOST_AUTO_TEST_CASE(even)
{
// Our median does not halve the difference (should it??), it just
// returns the next element from the input set
MedianFilter<double> f(4);
f.push(1); // 0 0 0 1
BOOST_CHECK_EQUAL(f.get(), 0);
BOOST_CHECK_EQUAL(f.get(), 0);
f.push(-3); // 0 0 1 -3
BOOST_CHECK_EQUAL(f.get(), 0);
f.push(5); // 0 1 -3 5
BOOST_CHECK_EQUAL(f.get(), 1);
f.push(7); // 1 -3 5 7
BOOST_CHECK_EQUAL(f.get(), 5);
BOOST_CHECK_EQUAL(f.get(), 5);
f.push(3); // -3 5 7 3
BOOST_CHECK_EQUAL(f.get(), 5);
f.push(3); // 5 7 3 3
BOOST_CHECK_EQUAL(f.get(), 5);
}
BOOST_AUTO_TEST_CASE(odd75)
{
MedianFilter<double> f(5, 75.f);
f.push(1); // 0 0 0 0 1
BOOST_CHECK_EQUAL(f.get(), 0);
BOOST_CHECK_EQUAL(f.get(), 0);
f.push(-3); // 0 0 0 1 -3
BOOST_CHECK_EQUAL(f.get(), 0);
f.push(5); // 0 0 1 -3 5
BOOST_CHECK_EQUAL(f.get(), 1);
f.push(7); // 0 1 -3 5 7
BOOST_CHECK_EQUAL(f.get(), 5);
BOOST_CHECK_EQUAL(f.get(), 5);
f.push(3); // 0 -3 5 7 3
BOOST_CHECK_EQUAL(f.get(), 5);
f.push(3); // 0 5 7 3 3
BOOST_CHECK_EQUAL(f.get(), 5);
}
BOOST_AUTO_TEST_CASE(even75)
{
MedianFilter<double> f(4, 75.f);
f.push(1); // 0 0 0 1
BOOST_CHECK_EQUAL(f.get(), 1);
BOOST_CHECK_EQUAL(f.get(), 1);
f.push(-3); // 0 0 1 -3
BOOST_CHECK_EQUAL(f.get(), 1);
f.push(5); // 0 1 -3 5
BOOST_CHECK_EQUAL(f.get(), 5);
f.push(7); // 1 -3 5 7
BOOST_CHECK_EQUAL(f.get(), 7);
BOOST_CHECK_EQUAL(f.get(), 7);
f.push(3); // -3 5 7 3
BOOST_CHECK_EQUAL(f.get(), 7);
f.push(3); // 5 7 3 3
BOOST_CHECK_EQUAL(f.get(), 7);
}
BOOST_AUTO_TEST_CASE(oddStandalone)
{
// The standalone (static filter() method) function is intended to
// match e.g. MATLAB median filter, filtering a row at once
// assuming the values beyond its edges are zeroes. This basically
// just means it needs to compensate for the latency in the raw
// filter:
//
// Raw filter
// 1 3 5 7 -> 0 1 3 5 (N=3)
// (because at each step only the values up to that step are
// available)
//
// Standalone function:
// 1 3 5 7 -> 1 3 5 5 (N=3)
std::vector<double> in;
in.push_back(1);
in.push_back(3);
in.push_back(5);
in.push_back(7);
std::vector<double> out = MedianFilter<double>::filter(3, in);
BOOST_CHECK_EQUAL(out[0], 1);
BOOST_CHECK_EQUAL(out[1], 3);
BOOST_CHECK_EQUAL(out[2], 5);
BOOST_CHECK_EQUAL(out[3], 5);
}
BOOST_AUTO_TEST_CASE(evenStandalone)
{
// See above. But note that the even length does not match the
// MATLAB because it doesn't halve the middle, as MATLAB does
std::vector<double> in;
in.push_back(1);
in.push_back(3);
in.push_back(5);
in.push_back(7);
std::vector<double> out = MedianFilter<double>::filter(4, in);
BOOST_CHECK_EQUAL(out[0], 3);
BOOST_CHECK_EQUAL(out[1], 5);
BOOST_CHECK_EQUAL(out[2], 5);
BOOST_CHECK_EQUAL(out[3], 5);
}
BOOST_AUTO_TEST_CASE(standaloneEmpty)
{
std::vector<double> in;
std::vector<double> out1 = MedianFilter<double>::filter(3, in);
BOOST_CHECK_EQUAL(out1.size(), 0);
std::vector<double> out2 = MedianFilter<double>::filter(4, in);
BOOST_CHECK_EQUAL(out2.size(), 0);
}
BOOST_AUTO_TEST_CASE(types)
{
MedianFilter<double> dfilt(3);
dfilt.push(1.2);
BOOST_CHECK_EQUAL(dfilt.get(), 0.0);
dfilt.push(2.4);
BOOST_CHECK_EQUAL(dfilt.get(), 1.2);
dfilt.push(1e-6);
BOOST_CHECK_EQUAL(dfilt.get(), 1.2);
dfilt.push(1e6);
BOOST_CHECK_EQUAL(dfilt.get(), 2.4);
MedianFilter<int> ifilt(3);
ifilt.push(1);
BOOST_CHECK_EQUAL(ifilt.get(), 0);
ifilt.push(2);
BOOST_CHECK_EQUAL(ifilt.get(), 1);
ifilt.push(0);
BOOST_CHECK_EQUAL(ifilt.get(), 1);
ifilt.push(1000);
BOOST_CHECK_EQUAL(ifilt.get(), 2);
}
BOOST_AUTO_TEST_CASE(inf)
{
// Inf and -Inf should behave normally
double pinf = strtod("Inf", 0);
double ninf = strtod("-Inf", 0);
MedianFilter<double> dfilt(3);
dfilt.push(1.0);
dfilt.push(2.0);
dfilt.push(pinf);
BOOST_CHECK_EQUAL(dfilt.get(), 2.0);
dfilt.push(pinf);
BOOST_CHECK_EQUAL(dfilt.get(), pinf);
dfilt.push(pinf);
BOOST_CHECK_EQUAL(dfilt.get(), pinf);
dfilt.push(2.0);
BOOST_CHECK_EQUAL(dfilt.get(), pinf);
dfilt.push(1.0);
BOOST_CHECK_EQUAL(dfilt.get(), 2.0);
dfilt.push(ninf);
BOOST_CHECK_EQUAL(dfilt.get(), 1.0);
dfilt.push(pinf);
BOOST_CHECK_EQUAL(dfilt.get(), 1.0);
dfilt.push(ninf);
BOOST_CHECK_EQUAL(dfilt.get(), ninf);
}
BOOST_AUTO_TEST_CASE(nan)
{
// The filter should never accept a NaN, because it breaks sorting
// and comparison and that will break the filter. Instead it
// should insert 0.
double nan = strtod("NaN", 0);
MedianFilter<double> dfilt(3);
dfilt.push(1.0);
dfilt.push(2.0);
dfilt.push(nan);
BOOST_CHECK_EQUAL(dfilt.get(), 1.0);
dfilt.push(nan);
BOOST_CHECK_EQUAL(dfilt.get(), 0.0);
dfilt.push(-11.0);
BOOST_CHECK_EQUAL(dfilt.get(), 0.0);
dfilt.push(-1.0);
BOOST_CHECK_EQUAL(dfilt.get(), -1.0);
}
BOOST_AUTO_TEST_SUITE_END()
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