/**
* An {@link Operation} that, given a binary image, produces a list of contours of all of the shapes
* in the image
*/
public class FindContoursOperation implements Operation {
private final SocketHint<Mat> inputHint =
new SocketHint.Builder<>(Mat.class).identifier("Input").build();
private final SocketHint<Boolean> externalHint =
SocketHints.createBooleanSocketHint("External Only", false);
private final SocketHint<ContoursReport> contoursHint =
new SocketHint.Builder<>(ContoursReport.class)
.identifier("Contours")
.initialValueSupplier(ContoursReport::new)
.build();
@Override
public String getName() {
return "Find Contours";
}
@Override
public String getDescription() {
return "Detect contours in a binary image.";
}
@Override
public Category getCategory() {
return Category.FEATURE_DETECTION;
}
@Override
public Optional<InputStream> getIcon() {
return Optional.of(getClass().getResourceAsStream("/edu/wpi/grip/ui/icons/find-contours.png"));
}
@Override
public InputSocket<?>[] createInputSockets(EventBus eventBus) {
return new InputSocket<?>[] {
new InputSocket<>(eventBus, inputHint), new InputSocket<>(eventBus, externalHint),
};
}
@Override
public OutputSocket<?>[] createOutputSockets(EventBus eventBus) {
return new OutputSocket<?>[] {new OutputSocket<>(eventBus, contoursHint)};
}
@Override
public Optional<?> createData() {
return Optional.of(new Mat());
}
@Override
@SuppressWarnings("unchecked")
public void perform(InputSocket<?>[] inputs, OutputSocket<?>[] outputs, Optional<?> data) {
final Mat input = ((InputSocket<Mat>) inputs[0]).getValue().get();
final Mat tmp = ((Optional<Mat>) data).get();
final boolean externalOnly = ((InputSocket<Boolean>) inputs[1]).getValue().get();
if (input.empty()) {
return;
}
// findContours modifies its input, so we pass it a temporary copy of the input image
input.copyTo(tmp);
// OpenCV has a few different things it can return from findContours, but for now we only use
// EXTERNAL and LIST.
// The other ones involve hierarchies of contours, which might be useful in some situations, but
// probably only
// when processing the contours manually in code (so, not in a graphical pipeline).
MatVector contours = new MatVector();
findContours(
tmp, contours, externalOnly ? CV_RETR_EXTERNAL : CV_RETR_LIST, CV_CHAIN_APPROX_TC89_KCOS);
final OutputSocket<ContoursReport> contoursSocket = (OutputSocket<ContoursReport>) outputs[0];
contoursSocket.setValue(new ContoursReport(contours, input.rows(), input.cols()));
}
}
