Connecting points with lines

Sensbellum

in Contributed Library Questions • 4 months ago

I have been working on this openCV project and I am looking to connect the final dots together, literally.

How can I get the points from the blobs to draw lines from one another?

I tried to make a PVector array from a few pieces of code and I feel like I am getting close just missing the last part.

import hypermedia.video.*;
import java.awt.Rectangle;
import java.awt.Point;
OpenCV opencv;
int LIMIT = 300;
int cvthreshold = 80;
int blur = 5;
PVector[] vex;
int numpoints;
void setup() {
size(640, 480, P3D);
opencv = new OpenCV(this);
opencv.allocate(640, 480);
opencv.capture(640, 480);
vex = new PVector[numpoints];
// for(int i = 0; i < vex.length; i++){
// vex[i] = new PVector(random(50,width-50), random(50,height-50));
//
// }
}
void draw() {
background(10);
opencv.read();
opencv.blur(OpenCV.BLUR, blur);
opencv.threshold(cvthreshold);
image(opencv.image(), 0, 0, 640, 480);
Blob[] blobs = opencv.blobs(20, width*height/50, 40, true);
int numpoints = blobs.length;
println("Number of points =" + numpoints);
noFill();
pushMatrix();
for (int i = 0; i < blobs.length; i++) {
Rectangle bounding_rect = blobs[i].rectangle;
float area = blobs[i].area;
float circumference = blobs[i].length;
Point centroid = blobs[i].centroid;
Point centroid2 = blobs[i].centroid;
stroke(255, 255, 255, 150);
strokeWeight(2);
// line(centroid.x, centroid.y, 0, 0); // Top Left
// line(centroid.x, centroid.y, 640, 0); // Top Right
// line(centroid.x, centroid.y, 0, 480); // Bottom Left
// line(centroid.x, centroid.y, 640, 480); // Bottom Right
noStroke();
stroke(255);
strokeWeight(5);
point(centroid.x, centroid.y);
noStroke();
fill(100, 100);
ellipse(centroid.x, centroid.y, 50, 50);
ellipse(centroid.x, centroid.y, 35, 35);
}
//// //DRAWS LINES
// for (int t = 0; t < vex.length; t++) {
// PVector pv1 = vex[t];
// for (int g = 0; g < vex.length; g++) {
// PVector pv2 = vex[g];
// float d = dist(pv1.x, pv1.y, pv2.x, pv2.y);
// if (d <= LIMIT) {
// line(pv1.x, pv1.y, pv2.x, pv2.y);
// }
// }
// }
popMatrix();
}
//This allows you to use the mouse the adjust blur and threshold
void mouseDragged() {
cvthreshold = int( map(mouseX, 0, width, 0, 255) );
blur = int( map(mouseY, 0, height, 50, 0) );
}

Replies(2)

tfguy44

Re: Connecting points with lines

4 months ago

Can't run your code because I don;t have that library or video.
But it seems like it should be simple to draw lines between the blobs' centers:

for (int i = 0; i < blobs.length; i++) {
Rectangle bounding_rect = blobs[i].rectangle;
float area = blobs[i].area;
float circumference = blobs[i].length;
Point centroid = blobs[i].centroid;
Point centroid2 = blobs[i].centroid;
stroke(255, 255, 255, 150);
strokeWeight(2);
// Just add in this block.
for( int j=i+1; j < blobs.length; j++ ){
Point other = blobs[j].centroid;
line( other.x, other.y, centroid.x, centroid.y);
}
// line(centroid.x, centroid.y, 0, 0); // Top Left
// line(centroid.x, centroid.y, 640, 0); // Top Right
// line(centroid.x, centroid.y, 0, 480); // Bottom Left
// line(centroid.x, centroid.y, 640, 480); // Bottom Right

Sensbellum

Re: Connecting points with lines

4 months ago

Thank you tfguy44 for the advice,

Luckily I was able to figure it out, I did not have the line drawing happening in the right order or in the correct for loop.

This example was instrumental in figuring out the right coding:

http://vormplus.be/blog/article/processing-month-day-2-connecting-points-part-2

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