Replace erroneous subtraction leading to underflow.

Instead allow selection between two new subtractions:
1. Absolute Difference
2. Saturated Difference (Truncation at 0,255 limits)

Src/Config.cpp

@@ -51,6 +51,7 @@ void Config::load(QString dir, QString file)
     config->EnableSwap = tree.get<int>(globalPrefix+"EnableSwap",config->EnableSwap);
     config->EnableAdd = tree.get<int>(globalPrefix+"EnableAdd",config->EnableAdd);
     config->EnableRotate = tree.get<int>(globalPrefix+"EnableRotate",config->EnableRotate);
+    config->UseAbsoluteDifference = tree.get<bool>(globalPrefix+"UseAbsoluteDifference",config->UseAbsoluteDifference);
     config->BinarizationThreshold = tree.get<int>(globalPrefix+"BinarizationThreshold",config->BinarizationThreshold);
     config->SizeErode = tree.get<int>(globalPrefix+"SizeErode",config->SizeErode);
     config->SizeDilate = tree.get<int>(globalPrefix+"SizeDilate",config->SizeDilate);
@@ -77,6 +78,7 @@ void Config::save(QString dir, QString file)
     tree.put(globalPrefix+"EnableSwap", config->EnableSwap);
     tree.put(globalPrefix+"EnableAdd", config->EnableAdd);
     tree.put(globalPrefix+"EnableRotate", config->EnableRotate);
+    tree.put(globalPrefix+"UseAbsoluteDifference", config->UseAbsoluteDifference);
     tree.put(globalPrefix+"BinarizationThreshold", config->BinarizationThreshold);
     tree.put(globalPrefix+"SizeErode", config->SizeErode);
     tree.put(globalPrefix+"SizeDilate", config->SizeDilate);

Src/Config.h

@@ -7,7 +7,9 @@
 class Config : public IConfig
 {
 public:
+	bool UseAbsoluteDifference = true;
 	int BinarizationThreshold = 40;
+
 	int SizeErode = 8;
 	int SizeDilate = 8;
 	int MinBlobSize = 40;

Src/Model/TrackerParameter.cpp

@@ -7,7 +7,7 @@ TrackerParameter::TrackerParameter(QObject *parent) :
 	
 	_cfg = static_cast<ControllerTrackingAlgorithm*>(parent)->getConfig();
 	
-
+	_UseAbsoluteDifference = _cfg->UseAbsoluteDifference;
 	_BinarizationThreshold = _cfg->BinarizationThreshold;
 	_SizeErode = _cfg->SizeErode;
 	_SizeDilate = _cfg->SizeDilate;
@@ -38,4 +38,17 @@ void TrackerParameter::setBinarizationThreshold(int x)
 int TrackerParameter::getBinarizationThreshold()
 {
 	return _BinarizationThreshold;
+}
+
+
+void TrackerParameter::setUseAbsoluteDifference(bool value)
+{
+	_UseAbsoluteDifference = value;
+	_cfg->UseAbsoluteDifference = value;
+	Q_EMIT notifyView();
+}
+
+bool TrackerParameter::getUseAbsoluteDifference()
+{
+	return _UseAbsoluteDifference;
 }
\ No newline at end of file

Src/Model/TrackerParameter.h

@@ -18,48 +18,58 @@ public slots:
 		_algorithm = algorithm;
 	}
 
+	void setUseAbsoluteDifference(bool x);
+	bool getUseAbsoluteDifference();
+
 	void setBinarizationThreshold(int x);
 	int getBinarizationThreshold();
 
 	int getSizeErode() { return _SizeErode; };
 	void setSizeErode(int x) {
 		_SizeErode = x;
+		_cfg->SizeErode = x;
 		Q_EMIT notifyView();
 	};
 
 	int getSizeDilate() { return _SizeDilate; };
 	void setSizeDilate(int x) {
 		_SizeDilate = x;
+		_cfg->SizeDilate = x;
 		Q_EMIT notifyView();
 	};
 
 	double getLearningRate() { return _LearningRate; };
 	void setLearningRate(double x) {
 		_LearningRate = x;
+		_cfg->LearningRate = x;
 		Q_EMIT notifyView();
 	};
 
 	double getMinBlobSize() { return _MinBlobSize; };
 	void setMinBlobSize(double x) {
 		_MinBlobSize = x;
+		_cfg->MinBlobSize = x;
 		Q_EMIT notifyView();
 	};
 
 	double getMaxBlobSize() { return _MaxBlobSize; };
 	void setMaxBlobSize(double x) {
 		_MaxBlobSize = x;
+		_cfg->MaxBlobSize = x;
 		Q_EMIT notifyView();
 	};
 
 	bool getDoBackground() { return _doBackground; };
 	void setDoBackground(bool x) {
 		_doBackground = x;
+		_cfg->DoBackground = x;
 		Q_EMIT notifyView();
 	};
 
 	bool getDoNetwork() { return _doNetwork; };
 	void setDoNetwork(bool x) {
 		_doNetwork = x;
+		_cfg->DoNetwork = x;
 		Q_EMIT notifyView();
 	};
 
@@ -86,38 +96,14 @@ public slots:
 	void setNewSelection(std::string x) {
 		_newSelection = x;
 	}
-	
-
-	void setAll(
-		int BinarizationThreshold,
-		int SizeErode,
-		int SizeDilate,
-		double LearningRate,
-		int minBlobSize, 
-		int maxBlobSize)
-	{
-		_BinarizationThreshold = BinarizationThreshold;
-		_SizeErode = SizeErode;
-		_SizeDilate = SizeDilate;
-		_LearningRate = LearningRate;
-		_MinBlobSize = minBlobSize;
-		_MaxBlobSize = maxBlobSize;
-		_cfg->BinarizationThreshold = BinarizationThreshold;
-		_cfg->SizeErode = SizeErode;
-		_cfg->SizeDilate = SizeDilate;
-		_cfg->MinBlobSize = minBlobSize;
-		_cfg->MaxBlobSize = maxBlobSize;
-		_cfg->LearningRate = LearningRate;
-		Q_EMIT notifyView();
-	};
-
-
 
 private:
 
 	QString _algorithm;
 
+	bool _UseAbsoluteDifference;
 	int _BinarizationThreshold;
+
 	int _SizeErode;
 	int _SizeDilate;
 	double _LearningRate;

Src/Model/TrackingAlgorithm/imageProcessor/preprocessor/CustomBackgroundSubtractor.cpp

@@ -5,6 +5,18 @@
 
 #include <opencv2/imgproc.hpp>
 
+CustomBackgroundSubtractor::CustomBackgroundSubtractor()
+: m_useAbsoluteDifference{true}
+, m_binarizationThreshold{8}
+{
+
+}
+
+void CustomBackgroundSubtractor::setUseAbsoluteDifference(bool value)
+{
+	m_useAbsoluteDifference = value;
+}
+
 void CustomBackgroundSubtractor::setBinarizationThreshold(int value)
 {
 	m_binarizationThreshold = value;
@@ -33,7 +45,9 @@ void CustomBackgroundSubtractor::apply(cv::InputArray image, cv::OutputArray fgm
 
 	auto fgmaskmat = fgmask.getMat();
 
-	auto workOnRegion = [&](int x, int y) {
+	const auto useAbsoluteDifference = m_useAbsoluteDifference;
+
+	auto workOnRegion = [&, useAbsoluteDifference](int x, int y) {
 		const int startingX = x * regionWidth;
 		const int startingY = y * regionHeight;
 		const cv::Rect subArea = cv::Rect(startingX, startingY, regionWidth, regionHeight);
@@ -41,7 +55,12 @@ void CustomBackgroundSubtractor::apply(cv::InputArray image, cv::OutputArray fgm
 		cv::Mat subImage = image.getMat()(subArea);
 		cv::Mat subResults = fgmaskmat(subArea);
 
-		subResults = (subBackground - subImage);
+		if (useAbsoluteDifference) {
+			cv::absdiff(subBackground, subImage, subResults);
+		} else {
+			cv::subtract(subBackground, subImage, subResults);
+		}
+
 		subBackground = (1.0 - learningRate) * subBackground + learningRate * subImage;
 	};
 

Src/Model/TrackingAlgorithm/imageProcessor/preprocessor/CustomBackgroundSubtractor.h

@@ -5,14 +5,19 @@
 class CustomBackgroundSubtractor : public cv::BackgroundSubtractor
 {
 public:
+	CustomBackgroundSubtractor();
+
 	void apply(cv::InputArray image, cv::OutputArray fgmask, double learningRate = -1) override;
 
 	void getBackgroundImage(cv::OutputArray backgroundImage) const override;
 
+	void setUseAbsoluteDifference(bool value);
 	void setBinarizationThreshold(int value);
 
 private:
 	cv::Mat m_background;
 
+	bool m_useAbsoluteDifference;
+
 	int m_binarizationThreshold;
 };

Src/Model/TrackingAlgorithm/imageProcessor/preprocessor/ImagePreProcessor.cpp

@@ -85,6 +85,7 @@ cv::Mat ImagePreProcessor::backgroundSubtraction(cv::Mat& image)
 		if (m_TrackingParameter->getAlgorithm() != QString("Custom")) {
 			init();
 		}
+		subtractor->setUseAbsoluteDifference(m_TrackingParameter->getUseAbsoluteDifference());
 		subtractor->setBinarizationThreshold(m_TrackingParameter->getBinarizationThreshold());
 	} else {
 		qFatal("Unsupported background subtraction algorithm");

Src/View/TrackerParameterView.cpp

@@ -5,6 +5,7 @@
 
 TrackerParameterView::TrackerParameterView(QWidget *parent, IController *controller, IModel *model) : IViewWidget(parent, controller, model),
 																																		_ui(new Ui::TrackerParameterView),
+																																		_useAbsDiff(nullptr),
 																																		_binThres(nullptr)
 {
 	_ui->setupUi(this);
@@ -31,6 +32,8 @@ TrackerParameterView::TrackerParameterView(QWidget *parent, IController *control
 	connect(_ui->lineEdit_7_learningRate, qOverload<double>(&QDoubleSpinBox::valueChanged), this, &TrackerParameterView::parametersChanged);
 
 	initSubtractorSpecificUI(_ui->algorithmCB->currentText());
+
+	_ui->algorithmCB->setEnabled(false);
 }
 
 TrackerParameterView::~TrackerParameterView()
@@ -46,11 +49,18 @@ void TrackerParameterView::initSubtractorSpecificUI(QString algorithm)
 		_ui->algorithmSpecificParameterLayout->removeRow(0);
 	}
 
-	if (_binThres) {
-		_binThres = nullptr;
-	}
+	_useAbsDiff = nullptr;
+	_binThres = nullptr;
 
 	if (algorithm == QString("Custom")) {
+		_useAbsDiff = new QCheckBox();
+		_useAbsDiff->setText(" ");
+		_useAbsDiff->setChecked(parameter->getUseAbsoluteDifference());
+		_ui->algorithmSpecificParameterLayout->addRow(tr("Use Absolute Difference:"), _useAbsDiff);
+
+		connect(_useAbsDiff, &QCheckBox::toggled, parameter, &TrackerParameter::setUseAbsoluteDifference);
+		connect(_useAbsDiff, &QCheckBox::toggled, this, &TrackerParameterView::parametersChanged);
+
 		_binThres = new QSpinBox();
 		_binThres->setMinimum(1);
 		_binThres->setMaximum(255);
@@ -85,6 +95,10 @@ void TrackerParameterView::getNotified()
 
 	_ui->lineEdit_7_learningRate->setValue(parameter->getLearningRate());
 
+	if (_useAbsDiff) {
+		_useAbsDiff->setChecked(parameter->getUseAbsoluteDifference());
+	}
+
 	if (_binThres) {
 		_binThres->setValue(parameter->getBinarizationThreshold());
 	}

Src/View/TrackerParameterView.h

@@ -5,6 +5,7 @@
 #include "../Model/TrackerParameter.h"
 
 #include <QSpinBox>
+#include <QCheckBox>
 
 namespace Ui {
 	class TrackerParameterView;
@@ -31,6 +32,8 @@ public:
 private:
     Ui::TrackerParameterView *_ui;
 
+    QCheckBox* _useAbsDiff;
+
     QSpinBox* _binThres;
 
 private slots: