Files
OpenSpace/src/util/histogram.cpp
Alexander Bock d7d279ea16 Happy new year
2022-01-01 12:32:55 +01:00

345 lines
11 KiB
C++

/*****************************************************************************************
* *
* OpenSpace *
* *
* Copyright (c) 2014-2022 *
* *
* Permission is hereby granted, free of charge, to any person obtaining a copy of this *
* software and associated documentation files (the "Software"), to deal in the Software *
* without restriction, including without limitation the rights to use, copy, modify, *
* merge, publish, distribute, sublicense, and/or sell copies of the Software, and to *
* permit persons to whom the Software is furnished to do so, subject to the following *
* conditions: *
* *
* The above copyright notice and this permission notice shall be included in all copies *
* or substantial portions of the Software. *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, *
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A *
* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT *
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF *
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE *
* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
****************************************************************************************/
#include <openspace/util/histogram.h>
#include <ghoul/logging/logmanager.h>
#include <ghoul/misc/assert.h>
#include <cmath>
namespace {
constexpr const char* _loggerCat = "Histogram";
} // namespace
namespace openspace {
Histogram::Histogram(float minValue, float maxValue, int numBins, float* data)
: _numBins(numBins)
, _minValue(minValue)
, _maxValue(maxValue)
, _data(data)
{
if (!data) {
_data = new float[numBins];
for (int i = 0; i < numBins; ++i) {
_data[i] = 0.0;
}
}
}
Histogram::~Histogram() {
delete[] _data;
}
int Histogram::numBins() const {
return _numBins;
}
float Histogram::minValue() const {
return _minValue;
}
float Histogram::maxValue() const {
return _maxValue;
}
bool Histogram::isValid() const {
return _numBins != -1;
}
bool Histogram::add(float value, float repeat) {
if (value < _minValue || value > _maxValue) {
// Out of range
return false;
}
const float normalizedValue = (value - _minValue) / (_maxValue - _minValue);
const int binIndex = static_cast<int>(std::min(
static_cast<float>(floor(normalizedValue * _numBins)),
_numBins - 1.f
)); // [0, _numBins - 1]
_data[binIndex] += repeat;
_numValues = static_cast<int>(_numValues + repeat);
return true;
}
void Histogram::changeRange(float minValue, float maxValue){
if (minValue > _minValue && maxValue < _maxValue) {
return;
}
float* oldData = _data;
float oldMin = _minValue;
float oldMax = _maxValue;
float* newData = new float[_numBins]{0.0};
for(int i=0; i<_numBins; i++){
float unNormalizedValue = i*(oldMax-oldMin)+oldMin;
float normalizedValue = (unNormalizedValue - _minValue) /
(_maxValue - _minValue); // [0.0, 1.0]
int binIndex = static_cast<int>(std::min(
static_cast<float>(floor(normalizedValue * _numBins)),
_numBins - 1.f
)); // [0, _numBins - 1]
newData[binIndex] = oldData[i];
}
_data = newData;
delete oldData;
_minValue = minValue;
_maxValue = maxValue;
}
bool Histogram::add(const Histogram& histogram) {
if (_minValue == histogram.minValue() &&
_maxValue == histogram.maxValue() &&
_numBins == histogram.numBins())
{
const float* data = histogram.data();
for (int i = 0; i < _numBins; i++) {
_data[i] += data[i];
}
_numValues += histogram._numValues;
return true;
}
else {
LERROR("Dimension mismatch");
return false;
}
}
bool Histogram::addRectangle(float lowBin, float highBin, float value) {
if (lowBin == highBin) {
return true;
}
if (lowBin > highBin) {
std::swap(lowBin, highBin);
}
if (lowBin < _minValue || highBin > _maxValue) {
// Out of range
return false;
}
const float normalizedLowBin = (lowBin - _minValue) / (_maxValue - _minValue);
const float normalizedHighBin = (highBin - _minValue) / (_maxValue - _minValue);
const float lowBinIndex = normalizedLowBin * _numBins;
const float highBinIndex = normalizedHighBin * _numBins;
const int fillLow = static_cast<int>(floor(lowBinIndex));
const int fillHigh = static_cast<int>(ceil(highBinIndex));
for (int i = fillLow; i < fillHigh; i++) {
_data[i] += value;
}
if (lowBinIndex > fillLow) {
const float diff = lowBinIndex - fillLow;
_data[fillLow] -= diff * value;
}
if (highBinIndex < fillHigh) {
const float diff = -highBinIndex + fillHigh;
_data[fillHigh - 1] -= diff * value;
}
return true;
}
float Histogram::interpolate(float bin) const {
const float normalizedBin = (bin - _minValue) / (_maxValue - _minValue);
const float binIndex = normalizedBin * _numBins - 0.5f; // Center
const float interpolator = binIndex - floor(binIndex);
int binLow = static_cast<int>(floor(binIndex));
int binHigh = static_cast<int>(ceil(binIndex));
// Clamp bins
if (binLow < 0) {
binLow = 0;
}
if (binHigh >= _numBins) {
binHigh = _numBins - 1;
}
return (1.f - interpolator) * _data[binLow] + interpolator * _data[binHigh];
}
float Histogram::sample(int binIndex) const {
ghoul_assert(binIndex >= 0 && binIndex < _numBins, "binIndex out of range");
return _data[binIndex];
}
const float* Histogram::data() const {
return _data;
}
std::vector<std::pair<float,float>> Histogram::getDecimated(int) const {
// Return a copy of _data decimated as in Ljung 2004
return std::vector<std::pair<float,float>>();
}
void Histogram::normalize() {
float sum = 0.0;
for (int i = 0; i < _numBins; i++) {
sum += _data[i];
}
for (int i = 0; i < _numBins; i++) {
_data[i] /= sum;
}
}
/*
* Will create an internal array for histogram equalization.
* Old histogram value is the index of the array, and the new equalized
* value will be the value at the index.
*/
void Histogram::generateEqualizer() {
float previousCdf = 0.0f;
_equalizer = std::vector<float>(_numBins, 0.0f);
for (int i = 0; i < _numBins; i++) {
const float probability = _data[i] / static_cast<float>(_numValues);
const float cdf = std::min(1.0f, previousCdf + probability);
_equalizer[i] = cdf * (_numBins-1);
previousCdf = cdf;
}
}
/*
* Will return a equalized histogram
*/
Histogram Histogram::equalize() {
Histogram equalizedHistogram(_minValue, _maxValue, _numBins);
for (int i = 0; i < _numBins; i++) {
equalizedHistogram._data[static_cast<int>(_equalizer[i])] += _data[i];
}
equalizedHistogram._numValues = _numValues;
return equalizedHistogram;
}
/*
* Given a value within the domain of this histogram (_minValue < value < maxValue),
* this method will use its equalizer to return a histogram equalized result.
*/
float Histogram::equalize(float value) const {
// if (value < _minValue || value > _maxValue) {
// LWARNING(
// "Equalized value is is not within domain of histogram. min: " +
// std::to_string(_minValue) + " max: " + std::to_string(_maxValue) +
// " val: " + std::to_string(value)
// );
// }
float normalizedValue = (value-_minValue)/(_maxValue-_minValue);
int bin = static_cast<int>(floor(normalizedValue * _numBins));
// If value == _maxValues then bin == _numBins, which is a invalid index.
bin = std::min(_numBins-1, bin);
bin = std::max(0, bin);
return _equalizer[bin];
}
float Histogram::entropy() {
float entropy = 0.f;
for (int i = 0; i < _numBins; ++i) {
if (_data[i] != 0) {
entropy -= (_data[i] / static_cast<float>(_numValues)) *
(log2(_data[i]) / static_cast<float>(_numValues));
}
}
return entropy;
}
std::vector<char> Histogram::getBinaryData() const {
std::vector<char> dataVector(
reinterpret_cast<char*>(_data),
reinterpret_cast<char*>(_data + _numValues)
);
return dataVector;
}
void Histogram::print() const {
//for (int i = 0; i < _numBins; i++) {
// //float low = _minValue + float(i) / _numBins * (_maxValue - _minValue);
// //float high = low + (_maxValue - _minValue) / float(_numBins);
// // std::cout << i << " [" << low << ", " << high << "]"
// // << " " << _data[i] << std::endl;
// std::cout << _data[i]/static_cast<float>(_numValues) << ", ";
//}
//std::cout << std::endl;
//// std::cout << std::endl << std::endl << std::endl<< "==============" << std::endl;
}
float Histogram::highestBinValue(bool equalized, int overBins){
int highestBin = 0;
float highestValue = 0;
for (int i = 0; i < _numBins; i++) {
float value = 0;
int num = 0;
for (int j=0; j<overBins; j++) {
if (i - j > 0) {
value += _data[i-j];
num++;
}
if (i + j < _numBins) {
value += _data[i+j];
num++;
}
}
value += _data[i];
value /= static_cast<float>(++num);
if (value > highestValue) {
highestBin = i;
highestValue = value;
}
}
if (!equalized) {
float low = _minValue + static_cast<float>(highestBin) /
_numBins * (_maxValue - _minValue);
float high = low + (_maxValue - _minValue) / static_cast<float>(_numBins);
return (high+low) / 2.f;
}
else {
return highestBin / static_cast<float>(_numBins);
// return equalize((high+low)/2.0);
}
}
float Histogram::binWidth() {
return (_maxValue - _minValue) / _numBins;
}
} // namespace openspace