Background/mask over webcam feed

Hi to whoever is reading this!

I am trying to create an overlay over a webcam feed. I am using the webcam to capture the darkest points in its vision, where it will draw a circle. However, in the end result I don’t want to see the actual webcam live feed. Just a white background, and the circles that are being drawn. Just setting the background to 255 in the setup doesn’t work. So I tried to use a mask with a white background image. But that doesn’t work as well. Obviously I don’t want to put anything in the draw function, because then I would lose the drawed circles. I feel like I am missing a clear solution here! I hope anyone can help me with this.

My code:

import gab.opencv.*;

Capture cam;
OpenCV opencv;
PVector prevLoc;
PImage maskImage;

void setup() {
  size(1920, 1080);
  background(255); // so this doesn't work lol
  maskImage = loadImage("background.png"); //doesn't work as well
  opencv = new OpenCV(this, 1920, 1080);
  String[] cameras = Capture.list();
  if (cameras.length == 0) {
    println("There are no cameras available for capture.");
  } else {
    println("Available cameras:");
    for (int i = 0; i < cameras.length; i++) {
    cam = new Capture(this, 1920, 1080, cameras[1]);
    cam.mask(maskImage); //I put the other line of the mask here, after I called the cam
    prevLoc = new PVector(0, width/2);

void captureEvent(Capture cam) {
  if (cam.available() == true) {;
  image(cam, 0, 0);

void draw() {
  PVector loc = opencv.min();
  ellipse(loc.x, loc.y, 50, 50);
  fill(random(255), random(255), random(255));
  prevLoc = loc;

void keyPressed() {
  if (key == ' ') {
1 Like

this line in captureEvent seemed to be called and end up drawn on the window. And you want to move background in draw so that it will wipe out everything from the previous frame.

edit: also! as written in the guideline, if you post on other forums, please link to them so people don’t have to duplicate effort


Deleting the image(cam, 0, 0); line helped :smiley: I’m so grateful, thank you so much!

I will delete the other post because you solved it, so it’s not needed anymore. I will keep it in mind for my next topics though :slight_smile: