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wrapper for optical flow (specifically Farneback dense technique, but designed to be extensible)
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Lines changed: 242 additions & 3 deletions

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‎examples/OpticalFlow/OpticalFlow.pde‎

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import gab.opencv.*;
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import processing.video.*;
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OpenCV opencv;
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Movie video;
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void setup() {
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size(568*2, 320);
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video = new Movie(this, "sample1.mov");
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opencv = new OpenCV(this, 568, 320);
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video.loop();
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video.play();
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}
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void draw() {
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background(0);
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opencv.loadImage(video);
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opencv.calculateOpticalFlow();
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image(video, 0, 0);
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translate(video.width,0);
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stroke(255,0,0);
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opencv.drawOpticalFlow();
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PVector aveFlow = opencv.getAverageFlow();
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int flowScale = 50;
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stroke(255);
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strokeWeight(2);
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line(video.width/2, video.height/2, video.width/2 + aveFlow.x*flowScale, video.height/2 + aveFlow.y*flowScale);
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}
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void movieEvent(Movie m) {
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m.read();
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}
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‎examples/OpticalFlow/data/sample1.mov‎

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‎resources/build.properties‎

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# This is used to compare different versions of the same library, and check if
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# an update is available.
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library.version=11
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library.version=12
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# The version as the user will see it.
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library.prettyVersion=0.5.0
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library.prettyVersion=0.5.1
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library.copyright=(c) 2013
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library.dependencies=?
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library.keywords=?
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tested.platform=osx,windows7
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tested.processingVersion=2.1.12
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tested.processingVersion=2.2.1
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# Include javadoc references into your project's javadocs.

‎src/gab/opencv/Flow.java‎

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package gab.opencv;
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import processing.core.*;
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import java.awt.Rectangle;
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import org.opencv.video.Video;
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import org.opencv.core.Mat;
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import org.opencv.core.CvType;
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import org.opencv.core.Core;
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import org.opencv.core.Scalar;
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public class Flow {
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private Mat prev;
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private Mat flow;
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private boolean hasFlow = false;
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private double pyramidScale = 0.5;
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private int nLevels = 4;
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private int windowSize = 8;
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private int nIterations = 2;
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private int polyN = 7;
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private double polySigma = 1.5;
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private int runningFlags = Video.OPTFLOW_FARNEBACK_GAUSSIAN;
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private PApplet parent;
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public Flow(PApplet parent) {
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flow = new Mat();
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this.parent = parent;
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}
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public int width(){
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return flow.width();
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}
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public int height(){
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return flow.height();
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}
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public boolean hasFlow(){
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return hasFlow;
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}
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public void calculateOpticalFlow(Mat m) {
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int flags = runningFlags;
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if (!hasFlow) {
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prev = m.clone();
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flags = Video.OPTFLOW_USE_INITIAL_FLOW;
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hasFlow = true;
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}
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Video.calcOpticalFlowFarneback(prev, m, flow, pyramidScale, nLevels, windowSize, nIterations, polyN, polySigma, flags);
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prev = m.clone();
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}
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public PVector getTotalFlowInRegion(int x, int y, int w, int h) {
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Mat region = flow.submat(y, y+h, x, x+w);
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Scalar total = Core.sumElems(region);
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return new PVector((float)total.val[0], (float)total.val[1]);
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}
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public PVector getAverageFlowInRegion(int x, int y, int w, int h) {
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PVector total = getTotalFlowInRegion(x, y, w, h);
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return new PVector(total.x/(flow.width() * flow.height()), total.y/(flow.width()*flow.height()));
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}
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public PVector getTotalFlow() {
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return getTotalFlowInRegion(0, 0, flow.width(), flow.height());
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}
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public PVector getAverageFlow() {
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return getAverageFlowInRegion(0, 0, flow.width(), flow.height());
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}
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public PVector getFlowAt(int x, int y){
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return new PVector((float)flow.get(y, x)[0], (float)flow.get(y, x)[1]);
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}
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public void draw() {
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int stepSize = 4;
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for (int y = 0; y < flow.height(); y+=stepSize) {
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for (int x = 0; x < flow.width(); x+=stepSize) {
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PVector flowVec = getFlowAt(x,y);
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parent.line(x, y, x+flowVec.x, y+flowVec.y);
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}
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}
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}
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public void setPyramidScale(double v){
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pyramidScale = v;
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}
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public double getPyramidScale(){
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return pyramidScale;
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}
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public void setLevels(int n){
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nLevels = n;
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}
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public int getLevels(){
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return nLevels;
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}
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public void setWindowSize(int s){
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windowSize = s;
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}
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public int getWindowSize(){
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return windowSize;
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}
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public void setIterations(int i){
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nIterations = i;
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}
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public int getIterations(){
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return nIterations;
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}
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public void setPolyN(int n){
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polyN = n;
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}
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public int getPolyN(){
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return polyN;
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}
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public void setPolySigma(double s){
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polySigma = s;
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}
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public double getPolySigma(){
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return polySigma;
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}
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}

‎src/gab/opencv/OpenCV.java‎

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import gab.opencv.ContourComparator;
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import gab.opencv.Histogram;
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import gab.opencv.Line;
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import gab.opencv.Flow;
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import java.awt.Rectangle;
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import java.awt.image.BufferedImage;
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public CascadeClassifier classifier;
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BackgroundSubtractorMOG backgroundSubtractor;
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public Flow flow;
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public final static String VERSION = "##library.prettyVersion##";
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public final static String CASCADE_FRONTALFACE = "haarcascade_frontalface_alt.xml";
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height = h;
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welcome();
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setupWorkingImages();
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setupFlow();
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matR = new Mat(height, width, CvType.CV_8UC1);
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matG = new Mat(height, width, CvType.CV_8UC1);
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matBGRA = new Mat(height, width, CvType.CV_8UC4);
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}
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private void setupFlow(){
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flow = new Flow(parent);
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}
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private void setupWorkingImages(){
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outputImage = parent.createImage(width,height, PConstants.ARGB);
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}
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setGray(foreground);
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}
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/**
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* Calculate the optical flow of the current image relative
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* to a running series of images (typically frames from video).
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* Optical flow is useful for detecting what parts of the image
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* are moving and in what direction.
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*
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*/
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public void calculateOpticalFlow(){
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flow.calculateOpticalFlow(getCurrentMat());
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}
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/*
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* Get the total optical flow within a region of the image.
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* Be sure to call calculateOpticalFlow() first.
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*
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*/
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public PVector getTotalFlowInRegion(int x, int y, int w, int h) {
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return flow.getTotalFlowInRegion(x, y, w, h);
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}
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/*
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* Get the average optical flow within a region of the image.
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* Be sure to call calculateOpticalFlow() first.
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*
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*/
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public PVector getAverageFlowInRegion(int x, int y, int w, int h) {
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return flow.getAverageFlowInRegion(x,y,w,h);
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}
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/*
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* Get the total optical flow for the entire image.
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* Be sure to call calculateOpticalFlow() first.
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*/
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public PVector getTotalFlow() {
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return flow.getTotalFlow();
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}
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/*
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* Get the average optical flow for the entire image.
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* Be sure to call calculateOpticalFlow() first.
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*/
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public PVector getAverageFlow() {
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return flow.getAverageFlow();
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}
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/*
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* Get the optical flow at a single point in the image.
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* Be sure to call calcuateOpticalFlow() first.
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*/
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public PVector getFlowAt(int x, int y){
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return flow.getFlowAt(x,y);
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}
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/*
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* Draw the optical flow.
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* Be sure to call calcuateOpticalFlow() first.
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*/
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public void drawOpticalFlow(){
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flow.draw();
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}
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/**
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* Flip the current image.
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*

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