The entropy of the image was added to the statistics.

app/docks/FramePropertiesDock.cpp

@@ -204,6 +204,11 @@ FramePropertiesDock::FramePropertiesDock( QWidget* parent, bool* pbMainPlaySwitc
   labelMedianValue = new QLabel;
   labelMedianValue->setAlignment( Qt::AlignRight | Qt::AlignVCenter );
 
+  QLabel* entropyLabel = new QLabel( tr( "Entropy:" ) );
+  entropyLabel->setAlignment( Qt::AlignLeft | Qt::AlignVCenter );
+  labelEntropyValue = new QLabel;
+  labelEntropyValue->setAlignment( Qt::AlignRight | Qt::AlignVCenter );
+
   QLabel* percentileLabel = new QLabel( tr( "Percentile:" ) );
   percentileLabel->setAlignment( Qt::AlignLeft | Qt::AlignVCenter );
   labelPercentileValue = new QLabel;
@@ -225,6 +230,8 @@ FramePropertiesDock::FramePropertiesDock( QWidget* parent, bool* pbMainPlaySwitc
   statisticsLayout->addWidget( labelStdDevValue, gridRow++, 1 );
   statisticsLayout->addWidget( medianLabel, gridRow, 0 );
   statisticsLayout->addWidget( labelMedianValue, gridRow++, 1 );
+  statisticsLayout->addWidget( entropyLabel, gridRow, 0 );
+  statisticsLayout->addWidget( labelEntropyValue, gridRow++, 1 );
 
   QGroupBox* statisticsGroup = new QGroupBox( tr( "Statistics" ) );
   statisticsGroup->setLayout( statisticsLayout );
@@ -474,6 +481,9 @@ void FramePropertiesDock::updateStatistiques()
     double median = frame->getMedian( channel, min, max );
     labelMedianValue->setText( value.setNum( median, 'f', 1 ) );
 
+    double entropy = frame->getEntropy( channel, min, max );
+    labelEntropyValue->setText( value.setNum( entropy, 'f', 2 ) );
+
     double percentile = ( pixels > 0 ? ( 100.0 * counts / pixels ) : 0.0 );
     labelPercentileValue->setText( value.setNum( percentile, 'f', 1 ) );
   }

app/docks/FramePropertiesDock.h

@@ -76,6 +76,7 @@ private:
   QLabel* labelMeanValue;
   QLabel* labelStdDevValue;
   QLabel* labelMedianValue;
+  QLabel* labelEntropyValue;
   QLabel* labelPercentileValue;
 
   QLabel* colorsLabel;

app/widgets/HistogramWidget.cpp

@@ -940,6 +940,10 @@ void HistogramWidget::paintEvent( QPaintEvent* )
     double median = frame->getMedian( m_channelType, 0, frame->getNumHistogramSegment() - 1 );
     tipText += value.setNum( median, 'f', 1 ) + cellEnd;
 
+    tipText += cellBeg + tr( "Entropy:" ) + cellMid;
+    double entropy = frame->getEntropy( m_channelType, 0, frame->getNumHistogramSegment() - 1 );
+    tipText += value.setNum( entropy, 'f', 2 ) + cellEnd;
+
     tipText += cellBeg + tr( "Percent:" ) + cellMid;
     double percentile = ( pixels > 0 ? ( 100.0 * counts / pixels ) : 0.0 );
     tipText += value.setNum( percentile, 'f', 1 ) + cellEnd;

lib/CalypFrame.cpp

@@ -1132,6 +1132,32 @@ double CalypFrame::getHistogramValue( unsigned channel, unsigned int bin )
   return d->m_puiHistogram[indexStart + bin];
 }
 
+double CalypFrame::getEntropy( unsigned channel, unsigned int start, unsigned int end )
+{
+  if( !d->m_bHasHistogram )
+    return 0;
+
+  channel = d->getRealHistogramChannel( channel );
+  if( channel < 0 )
+    return 0;
+
+  int indexStart = channel * d->m_uiHistoSegments;
+  double numValues = getNumPixelsRange( channel, start, end );
+  double entropy = 0.0;
+
+  for( unsigned b = start; b < end; b++ )
+  {
+    if (d->m_puiHistogram[indexStart + b] == 0)
+      continue;
+
+    double prob = d->m_puiHistogram[indexStart + b] / numValues;
+
+    entropy -= prob * log2(prob);
+  }
+
+  return entropy;
+}
+
 /*
  **************************************************************
  * interface to other libs

lib/CalypFrame.h

@@ -382,6 +382,7 @@ public:
   double getHistogramValue( unsigned channel, unsigned int bin );
   unsigned int getNEBins( unsigned channel );
   int getNumHistogramSegment();
+  double getEntropy( unsigned channel, unsigned int start, unsigned int end );
 
   /**
 	 * interface with OpenCV lib