Changing the PImage colour if images overlap

Processing Libraries
1

How do i change the tint() of an PImage if the detected face is next to the PImage.

another%20one
another one.png960×568 838 KB 

import gab.opencv.*;
import processing.video.*;
import java.awt.*;

PImage img;
PImage background;
PImage imgCoral;

color colCoral;

Capture video;
OpenCV opencv;

void setup() {
size(960, 540);
colorMode (HSB);

frameRate(60);
  
  img = loadImage ("photo1.png");
    
  background=loadImage ("sea1.png");
  imgCoral = loadImage ("coral1.png");
  
  video = new Capture(this, 640, 480);
  opencv = new OpenCV(this, 640, 480);
  opencv.loadCascade(OpenCV.CASCADE_FRONTALFACE); 
  
  video.start();
  
}

void draw() {
  background (background);
  tint(50);
  image(imgCoral,0,0);
  tint(255,255);
  scale(1);
  opencv.loadImage(video);
       
  noFill();
  stroke(0, 0, 0);
  strokeWeight(3);
  Rectangle[] faces = opencv.detect();
  println(faces.length);

  for (int i = 0; i < faces.length; i++) {
    println(faces[i].x + "," + faces[i].y);
    image(img, faces[i].x, faces[i].y, faces[i].width,faces[i].height);

  }
  
}


void captureEvent(Capture c) {
  c.read();
}

``