Add solidity filter

Author: ThomasJClark

core/src/main/java/edu/wpi/grip/core/operations/composite/ContoursReport.java

@@ -6,10 +6,8 @@
 
 import java.util.Optional;
 
-import static org.bytedeco.javacpp.opencv_core.MatVector;
-import static org.bytedeco.javacpp.opencv_core.Rect;
-import static org.bytedeco.javacpp.opencv_imgproc.boundingRect;
-import static org.bytedeco.javacpp.opencv_imgproc.contourArea;
+import static org.bytedeco.javacpp.opencv_core.*;
+import static org.bytedeco.javacpp.opencv_imgproc.*;
 
 /**
  * The output of {@link FindContoursOperation}.  This stores a list of contours (which is basically a list of points) in
@@ -113,4 +111,15 @@ public synchronized double[] getHeights() {
         }
         return heights;
     }
+
+    @NTValue(key = "solidity")
+    public synchronized double[] getSolidity() {
+        final double[] solidities = new double[(int) contours.size()];
+        Mat hull = new Mat();
+        for (int i = 0; i < contours.size(); i++) {
+            convexHull(contours.get(i), hull);
+            solidities[i] = contourArea(contours.get(i)) / contourArea(hull);
+        }
+        return solidities;
+    }
 }

core/src/main/java/edu/wpi/grip/core/operations/composite/FilterContoursOperation.java

@@ -4,6 +4,7 @@
 import edu.wpi.grip.core.*;
 
 import java.io.InputStream;
+import java.util.List;
 import java.util.Optional;
 
 import static org.bytedeco.javacpp.opencv_core.*;
@@ -41,6 +42,9 @@ public class FilterContoursOperation implements Operation {
     private final SocketHint<Number> maxHeightHint =
             SocketHints.Inputs.createNumberSpinnerSocketHint("Max Height", 1000, 0, Integer.MAX_VALUE);
 
+    private final SocketHint<List> solidityHint =
+            SocketHints.Inputs.createNumberListRangeSocketHint("Solidity", 0, 100);
+
     @Override
     public String getName() {
         return "Filter Contours";
@@ -66,6 +70,7 @@ public InputSocket<?>[] createInputSockets(EventBus eventBus) {
                 new InputSocket<>(eventBus, maxWidthHint),
                 new InputSocket<>(eventBus, minHeightHint),
                 new InputSocket<>(eventBus, maxHeightHint),
+                new InputSocket<>(eventBus, solidityHint),
         };
     }
 
@@ -84,22 +89,31 @@ public void perform(InputSocket<?>[] inputs, OutputSocket<?>[] outputs) {
         final double maxWidth = ((Number) inputs[4].getValue().get()).doubleValue();
         final double minHeight = ((Number) inputs[5].getValue().get()).doubleValue();
         final double maxHeight = ((Number) inputs[6].getValue().get()).doubleValue();
+        final double minSolidity = ((List<Number>) inputs[7].getValue().get()).get(0).doubleValue();
+        final double maxSolidity = ((List<Number>) inputs[7].getValue().get()).get(1).doubleValue();
 
         final MatVector inputContours = inputSocket.getValue().get().getContours();
         final MatVector outputContours = new MatVector(inputContours.size());
+        final Mat hull = new Mat();
 
         // Add contours from the input vector to the output vector only if they pass all of the criteria (minimum
-        // area, minimum perimeter, width, and height)
+        // area, minimum perimeter, width, and height, etc...)
         int filteredContourCount = 0;
         for (int i = 0; i < inputContours.size(); i++) {
             final Mat contour = inputContours.get(i);
-            final Rect bb = boundingRect(contour);
 
-            if (contourArea(contour) < minArea) continue;
-            if (arcLength(contour, true) < minPerimeter) continue;
+            final Rect bb = boundingRect(contour);
             if (bb.width() < minWidth || bb.width() > maxWidth) continue;
             if (bb.height() < minHeight || bb.height() > maxHeight) continue;
 
+            final double area = contourArea(contour);
+            if (area < minArea) continue;
+            if (arcLength(contour, true) < minPerimeter) continue;
+
+            convexHull(contour, hull);
+            final double solidity = 100 * area / contourArea(hull);
+            if (solidity < minSolidity || solidity > maxSolidity) continue;
+
             outputContours.put(filteredContourCount++, contour);
         }