Fix bug when measuring quality of frame with only one component

app/docks/QualityMeasurementSidebar.cpp

@@ -197,7 +197,6 @@ void QualityMeasurementSidebar::updateSidebarData()
       }
       for( ; component < 3; component++ )
       {
-        quality = currFrame->getQuality( m_comboBoxMetric->currentIndex(), refFrame, component );
         m_ppcLabelQualityValue[component]->setText( zeroValue );
       }
       return;

lib/CalypFrame.cpp

@@ -1153,6 +1153,10 @@ std::vector<ClpString> CalypFrame::supportedQualityMetricsList()
 
 double CalypFrame::getQuality( int Metric, CalypFrame* Org, int component )
 {
+  if( component >= getNumberChannels() )
+  {
+    return 0;
+  }
   switch( Metric )
   {
   case PSNR_METRIC: