Made --cluster skip empty images

tools/imglab/src/cluster.cpp

@@ -111,6 +111,18 @@ double mean_aspect_ratio (
 
 // ----------------------------------------------------------------------------------------
 
+bool has_non_ignored_boxes (const image_dataset_metadata::image& img)
+{
+    for (auto&& b : img.boxes)
+    {
+        if (!b.ignore)
+            return true;
+    }
+    return false;
+}
+
+// ----------------------------------------------------------------------------------------
+
 int cluster_dataset(
     const dlib::command_line_parser& parser
 )
@@ -140,8 +152,9 @@ int cluster_dataset(
     for (unsigned long i = 0; i < data.images.size(); ++i)
     {
         pbar.print_status(i);
-        if (data.images[i].boxes.size() == 0)
+        if (!has_non_ignored_boxes(data.images[i]))
             continue;
+
         array2d<rgb_pixel> img, chip;
         load_image(img, data.images[i].filename);
 
@@ -181,8 +194,9 @@ int cluster_dataset(
         {
             idata[i].first = std::numeric_limits<double>::infinity();
             idata[i].second.filename = data.images[i].filename;
-            if (data.images[i].boxes.size() == 0)
+            if (!has_non_ignored_boxes(data.images[i]))
                 continue;
+
             for (unsigned long j = 0; j < data.images[i].boxes.size(); ++j)
             {
                 idata[i].second.boxes.push_back(data.images[i].boxes[j]);