public boolean accepts(MapContext mc, ILayer layer) {
   try {
     if (layer.isRaster()) {
       SpatialDataSourceDecorator ds = layer.getDataSource();
       if (ds.getRaster(0).getType() != ImagePlus.COLOR_RGB) {
         return true;
       }
     }
   } catch (IOException e) {
   } catch (DriverException e) {
   }
   return false;
 }