ofxGrabMask

OpenFrameworks addon for object segmentation and shape feature extraction.

Features

• Interactive object segmentation using GrabCut algorithm
• Various shape feature extraction methods:
• Hu Moments
• Fourier Descriptors
• Shape Context
• Inner Distance
• Curvature Features
• Skeleton Features
• Visualization of extracted features
• Simple drag & drop interface

Requirements

• OpenFrameworks 0.11.0+
• ofxCv addon
• OpenCV 4.0+

Usage

#include "ofxGrabMask.h"

ofxGrabMask grabMask;

void ofApp::setup() {
    grabMask.setup();
}

void ofApp::update() {
    grabMask.update();
}

void ofApp::draw() {
    grabMask.draw();
}

// Forward mouse and window events to the grabMask
void ofApp::mouseMoved(int x, int y) {
    grabMask.mouseMoved(x, y);
}

void ofApp::mouseDragged(int x, int y, int button) {
    grabMask.mouseDragged(x, y, button);
}

void ofApp::mousePressed(int x, int y, int button) {
    grabMask.mousePressed(x, y, button);
}

void ofApp::mouseReleased(int x, int y, int button) {
    grabMask.mouseReleased(x, y, button);
}

void ofApp::windowResized(int w, int h) {
    grabMask.windowResized(w, h);
}

void ofApp::dragEvent(ofDragInfo dragInfo) {
    grabMask.dragEvent(dragInfo);
}

How it works

1. Drag and drop an image onto the application window 2. Draw a rectangle around the object you want to segment 3. The GrabCut algorithm will extract the object from the background 4. Right-click to access the feature extraction menu 5. Select a feature extraction method to analyze the shape

Methods

Setup and Main Loop

• setup(): Initialize the addon
• update(): Update internal state
• draw(): Draw the current state to the screen

Event Handlers

• mouseMoved(int x, int y): Handle mouse movement
• mouseDragged(int x, int y, int button): Handle mouse dragging
• mousePressed(int x, int y, int button): Handle mouse press
• mouseReleased(int x, int y, int button): Handle mouse release
• dragEvent(ofDragInfo dragInfo): Handle drag and drop events

Feature Extraction

• calculateHuMoments(): Calculate Hu moment invariants
• calculateFourierDescriptors(): Calculate Fourier descriptors
• calculateShapeContext(): Calculate shape context features
• calculateInnerDistance(): Calculate inner distance features
• calculateCurvature(): Calculate curvature features
• calculateSkeletonFeatures(): Calculate skeleton-based features

License

MIT License

Author

@bemoregt