Blob find contours

gius

Hello everyone, I'm using this code:

https://github.com/atduskgreg/opencv-processing/blob/master/examples/FindContours/FindContours.pde

I wish by pressing the button B the contour which found, will reset and becomes ready for a new image.

import g4p_controls.*;
import java.awt.Font;
import gab.opencv.*;

PImage src, dst;
OpenCV opencv;

ArrayList<Contour> contours;
ArrayList<Contour> polygons;

GButton btnFilterA;
boolean filterA=false;

GButton btnFilterB;
boolean filterB=false;

void setup() {
  src = loadImage("1.jpg"); 
  size(1024, 768);
  opencv = new OpenCV(this, src);

  btnFilterA = new GButton(this, 600, 20, 140, 20);
  btnFilterA.setText("Go");
  btnFilterA.setLocalColorScheme(GCScheme.GREEN_SCHEME);

  btnFilterB = new GButton(this, 750, 20, 140, 20);
  btnFilterB.setText("Stop");
  btnFilterB.setLocalColorScheme(GCScheme.GREEN_SCHEME);

  //opencv.gray();
  //opencv.threshold(70);
  //dst = opencv.getOutput();

  contours = opencv.findContours();
  println("found " + contours.size() + " contours");
}

void draw() {
  //scale(0.5);
  image(src, 0, 0);
  //image(dst, src.width, 0);

  noFill();
  strokeWeight(3);

  for (Contour contour : contours) {

    beginShape();
    for (PVector point : contour.getPolygonApproximation().getPoints()) {
    if (filterA==true){
    stroke(0, 255, 0);
    contour.draw();
    stroke(255, 0, 0);
    vertex(point.x, point.y); 

    }
    endShape();
  }
}
}

public void handleButtonEvents(GButton button, GEvent event) {

  if (button == btnFilterA) {
     filterA=true;
  }
    if (button == btnFilterB) {
     contour.clear();

  }
  }

I tried with my code but even if off the contour remains in "memory" of the contour, how I can fix?

thanks

kfrajer

Notice your endShape is not in the same scope as your beginShape. Move line 57 one curly bracket out.

To test if the array is being cleared out, try this:

void mouseReleased(){
  println("Found " + contours.size() + " contours");
  contours.clear();
  println("Now found " + contours.size() + " contours");
}

In your code, line 68, you should be calling contours and not contour. This is what I disagree naming variables and containers following classes names. Very easy to create a bug and hard to track them. I will suggest spicing the names of your objects. It will make them more maintainable at the end as well.

Kf

gius

Thanks kfrajer for your help, I have corrected the error (contours) but I have not understand where to enter endShape();

new code is:

import g4p_controls.*;
import java.awt.Font;
import gab.opencv.*;

OpenCV opencv;

ArrayList<Contour> contours;
ArrayList<Contour> polygons;

PImage canvas;


GButton btnFilterO;

boolean filterO=false;


void setup() {
  opencv = new OpenCV(this, canvas);
  contours = opencv.findContours();



  btnFilterO = new GButton(this, 180, 20, 140, 20);
  btnFilterO.setText("Open file");
  btnFilterO.setLocalColorScheme(GCScheme.GREEN_SCHEME);


  noFill();

}

void settings() {

  selectInput("Please select canvas picture:", "selectImage");
  while (canvas == null)  delay(100);
  size(canvas.width, canvas.height);
  noSmooth();

}

void draw() {
  background(canvas);
  loadPixels();
  canvas.loadPixels();
  canvas.updatePixels();
  strokeWeight(5);

  for (Contour contour : contours) {

    stroke(0, 255, 0);
    contour.draw();
    stroke(255, 0, 0);
    beginShape();

    for (PVector point : contour.getPolygonApproximation().getPoints()) {
    vertex(point.x, point.y); 
   }     
   endShape();
    }

  }



void selectImage(final File f) {
  if (f == null || f.isDirectory()) {

    println("Window was closed or you've hit cancel.\n");
    System.exit(0);
  }

  final String canvasPath = f.getPath();
  println(canvasPath);

  if ((canvas = loadImage(canvasPath)) == null) {
    println("is an invalid image file. Try again...\n");
    selectInput("Please select canvas picture:", "selectImage");

  }
 }

public void handleButtonEvents(GButton button, GEvent event) {


    if (button == btnFilterO) {

     selectInput("Please select canvas picture:", "selectImage"); 
  }

}

void mouseReleased(){
  println("Found " + contours.size() + " contours");
  contours.clear();
  println("Now found " + contours.size() + " contours");
}

every time I open a new file, it do not see the new contour, how can I fix?

thanks

kfrajer

Right. If you post the code in the Processing IDE (aka. not here), select all your code and hit ctrl+T. This will autoformat your code. Then if you check the scope of beginShape and endShape, they are not under the same block aka. under the same curling bracket block.

Kf

kfrajer

Ok, I also would recommend changing the way you are defining your size as you first image defines the size of your canvas. Instead, start with a pre-defined size and then when you load the image, you resize it. As it is right now for example, when I open a second image, if it is not the same size as the first image, it will throw an error.

Also I do not think it is a good approach to call your selectImage() recursively.

I will do instead (pseudo-code and not tested)

Kf

//Global field
boolean requestImageStage=false;

void selectImage(final File f) {
  if (f == null || f.isDirectory()) {

    println("Window was closed or you've hit cancel.\n");
    System.exit(0);
  }

  final String canvasPath = f.getPath();
  println(canvasPath);
  canvas = loadImage(canvasPath); 
  requestImageStage=false;  //Completed
  contours.clear();   //// REMOVE any previous contours as new image loaded!

  if(canvas!=null){
    //THIS is assuming you fixed your settings as I mentioned above
     canvas.resize(width,height);  
  }
 } 

and it draw():

void draw(){
 if (canvas == null && requestImageStage!=true) {

    background(0);
    println("is an invalid image file. Try again...\n");
    requestImageStage=true;
    selectInput("Please select canvas picture:", "selectImage"); 
  }
  else{
    background(canvas);
  }

  ....REST of the code omitted 

}

gius

Now I try, thank you!

gius

I have tried all your advice and this is the code:

import g4p_controls.*;
import java.awt.Font;
import gab.opencv.*;




OpenCV opencv;

ArrayList<Contour> contours;
ArrayList<Contour> polygons;

PImage canvas;
float ratio;
int n = 1;



GButton btnFilterO;

boolean filterO=false;
boolean requestImageStage=false;




void setup() {
  opencv = new OpenCV(this, canvas);
  contours = opencv.findContours();

  btnFilterO = new GButton(this, 180, 20, 140, 20);
  btnFilterO.setText("Open file");
  btnFilterO.setLocalColorScheme(GCScheme.GREEN_SCHEME);

  noFill();
}

void settings() {

  selectInput("Please select canvas picture:", "selectImage");
  while (canvas == null)  delay(100);
  size(canvas.width, canvas.height);

  noSmooth();
}

void draw() {
  if (canvas == null && requestImageStage!=true) {

    background(0);
    println("is an invalid image file. Try again...\n");
    requestImageStage=true;
    selectInput("Please select canvas picture:", "selectImage");
  } else {
    background(canvas);
    loadPixels();
    canvas.loadPixels();
    canvas.updatePixels();
    strokeWeight(5);
  }


  for (Contour contour : contours) {

    stroke(0, 255, 0);
    contour.draw();
    stroke(255, 0, 0);
    beginShape();

    for (PVector point : contour.getPolygonApproximation().getPoints()) {
      vertex(point.x, point.y);
    }
    endShape();
  }
}


void selectImage(final File f) {
  if (f == null || f.isDirectory()) {

    println("Window was closed or you've hit cancel.\n");
    System.exit(0);
  }

  final String canvasPath = f.getPath();
  println(canvasPath);
  canvas = loadImage(canvasPath); 
  requestImageStage=false;  //Completed
  contours.clear();   //// REMOVE any previous contours as new image loaded!

  if (canvas!=null) {
    //THIS is assuming you fixed your settings as I mentioned above
    canvas.resize(width, height);
  }
} 

public void handleButtonEvents(GButton button, GEvent event) {


  if (button == btnFilterO) {

    selectInput("Please select canvas picture:", "selectImage");
  }
}

but when I open the new image does not work detention of the contour, it works only the first time, I have this error:

ConcurrentModificationException for (Contour contour : contours) {

maybe I wrong something?

thanks

kfrajer

This works.

Kf

import g4p_controls.*;
import java.awt.Font;
import gab.opencv.*;

OpenCV opencv;

ArrayList<Contour> contours;
ArrayList<Contour> polygons;

PImage canvas;
float ratio;
int n = 1;

GButton btnFilterO;

boolean filterO=false;
boolean requestImageStage=false;


void setup() {
  size(960, 720);

  //surface.setResizable(true);
  btnFilterO = new GButton(this, 180, 20, 140, 20);
  btnFilterO.setText("Open file");
  btnFilterO.setLocalColorScheme(GCScheme.GREEN_SCHEME);

  noFill();
  noSmooth();
  strokeWeight(5);
}


void draw() {
  if (canvas == null ) {
    if (requestImageStage!=true) {
      background(0);
      requestImageStage=true;
      selectInput("Please select canvas picture:", "selectImage");
    }
  } else {

    if (requestImageStage==true) {
      //surface.setSize(canvas.width, canvas.height);
      canvas.resize(width, height);

      opencv = new OpenCV(this, canvas);
      contours = opencv.findContours();
      requestImageStage=false;
    } else {


      background(canvas);
      loadPixels();
      canvas.loadPixels();


      for (Contour contour : contours) {

        stroke(0, 255, 0);
        contour.draw();
        stroke(255, 0, 0);
        beginShape();
        for (PVector point : contour.getPolygonApproximation().getPoints()) {
          vertex(point.x, point.y);
        }
        endShape();
      }
    }
  }
}

void keyPressed() {
  if (contours==null) {
    println("It is null");
  } else {
    println("Found " + contours.size());
  }
}


void selectImage(final File f) {
  if (f == null || f.isDirectory()) {

    println("Window was closed or you've hit cancel.\n");
    System.exit(0);
  }

  final String canvasPath = f.getPath();
  println(canvasPath);
  canvas = loadImage(canvasPath); 
  //contours.clear();   //// REMOVE any previous contours as new image loaded!

  if (canvas!=null)   
    canvas.resize(width, height);
} 

public void handleButtonEvents(GButton button, GEvent event) {

  if (button == btnFilterO) {
    selectInput("Please select canvas picture:", "selectImage");
  }
}

kfrajer

Improved by using stages.

Kf

import g4p_controls.*;
import java.awt.Font;
import gab.opencv.*;

OpenCV opencv;

final int kLoadingStage=0;
final int kProcessingStage=1;
final int kReady=2;

ArrayList<Contour> contours;
ArrayList<Contour> polygons;

PImage canvas;
float ratio;
int n = 1;

GButton btnFilterO;

boolean filterO=false;
int  requestImageStage=kLoadingStage;


void setup() {
  size(960, 720);

  //surface.setResizable(true);
  btnFilterO = new GButton(this, 180, 20, 140, 20);
  btnFilterO.setText("Open file");
  btnFilterO.setLocalColorScheme(GCScheme.GREEN_SCHEME);

  noFill();
  noSmooth();
  strokeWeight(5);
}


void draw() {
  if (canvas == null ) {
    if (requestImageStage!=kLoadingStage) {
      background(0);      
      selectInput("Please select canvas picture:", "selectImage");
    }
  } else {

    if (requestImageStage==kProcessingStage) {

      opencv = new OpenCV(this, canvas);
      contours = opencv.findContours();
      requestImageStage=kReady;
    } else {

      background(canvas);

      loadPixels();
      canvas.loadPixels();


      for (Contour contour : contours) {

        stroke(0, 255, 0);
        contour.draw();
        stroke(255, 0, 0);
        beginShape();
        for (PVector point : contour.getPolygonApproximation().getPoints()) {
          vertex(point.x, point.y);
        }
        endShape();
      }
    }
  }
}

void keyPressed() {
  if (contours==null) {
    println("It is null");
  } else {
    println("Found " + contours.size());
  }
}


void selectImage(final File f) {
  if (f == null || f.isDirectory()) {

    println("Window was closed or you've hit cancel.\n");
    System.exit(0);
  }

  final String canvasPath = f.getPath();
  println(canvasPath);
  canvas = loadImage(canvasPath); 
  //contours.clear();   //// REMOVE any previous contours as new image loaded!

  if (canvas!=null) {
    //canvas.resize(width, height);
    surface.setSize(canvas.width, canvas.height);
    requestImageStage=kProcessingStage;    
  }
} 

public void handleButtonEvents(GButton button, GEvent event) {

  if (button == btnFilterO) {
    requestImageStage=kLoadingStage;
    selectInput("Please select canvas picture:", "selectImage");
  }
}

gius

Thanks kfrajer for your great help, everything works well, thanks again!