Dynamic reconfigure of alpha blending

README.md

@@ -69,3 +69,9 @@ In another terminal open the dynamic reconfigure and play around with the parame
 
 End the program execution with `Ctrl + C` keyboard shortcut. 
 
+
+### TO DO:
+- Display events using a fixed number of them (currently we are displaying the events as arranged in messages)
+- Display events using a fixed time interval
+- Allow interaction, to change the number of events or the size of the time slice
+- Add visualization of time surfaces

cfg/dvs_displayer.cfg

@@ -12,5 +12,11 @@ gen = ParameterGenerator()
 gen.add("Event_colormap", int_t, 0,
 "An Integer parameter", 0,  0, 12)
 
+gen.add("Blending", bool_t, 0,
+"Blend image? (True) or replace pixels (False)", True)
+
+gen.add("Blend_alpha", double_t, 0,
+"Blending factor. 0 -> show only events; 1 -> show only frame (if available)", 0.5, 0, 1)
+
 
 exit(gen.generate(PACKAGE, "displayer_node", "dvs_displayer"))

include/dvs_displayer/displayer.h

@@ -47,6 +47,8 @@ class Displayer {
   dynamic_reconfigure::Server<dvs_displayer::dvs_displayerConfig>::CallbackType dynamic_reconfigure_callback_;
 
   int event_colormap_idx_;
+  bool blend_enabled_;
+  double blend_alpha_;
 };
 
 } // namespace

src/displayer.cpp

@@ -169,9 +169,26 @@ void Displayer::eventsCallback(const dvs_msgs::EventArray::ConstPtr& msg)
       cv::LUT(gray_image3ch, cmap_, cm_img);
     }
 
-    // alpha-blending
-    const double alpha = 0.5;
-    cv::addWeighted( cv_image.image, alpha, cm_img, 1.-alpha, 0., cv_image.image);
+    // Fusion mode: blending or masking (pixel replacement)?
+    if (blend_enabled_)
+    {
+      // alpha-blending
+      cv::addWeighted( cv_image.image, blend_alpha_, cm_img, 1.-blend_alpha_, 0., cv_image.image);
+    }
+    else
+    {
+      // Pixel replacement
+      for (int ir=0; ir < cv_image.image.rows; ir++)
+      {
+        for (int ic=0; ic < cv_image.image.cols; ic++)
+        {
+          if(gray_image.at<uint8_t>(ir,ic) != 128)
+          {
+            cv_image.image.at<cv::Vec3b>(ir,ic) = cm_img.at<cv::Vec3b>(ir,ic);
+          }
+        }
+      }
+    }
 
   }
   else
@@ -190,6 +207,8 @@ void Displayer::seismic_cmap(cv::Mat& lut)
 void Displayer::reconfigureCallback(dvs_displayer::dvs_displayerConfig &config, uint32_t level)
 {
   event_colormap_idx_ = config.Event_colormap;
+  blend_enabled_ = config.Blending;
+  blend_alpha_ = config.Blend_alpha;
 }
 
 } // namespace