OpenCV face detection + Servo and Arduino

psica80

OpenCV face detection + Servo and Arduino

in Integration and Hardware • 1 years ago

I am very new in Programming (actually completely new at this) and I am developing a project which require that the servo will move according to the movement of the person. I found a code online about how to make it move according to face detection and it works. The idea is that the servo moves from 90 to 180 degrees and it works great according to the Y position of the face. However my project requires also time so for example if you move too fast the servo position will go back immediately to 90 degrees

This is the Processing code:

import hypermedia.video.*; //Include the video library to capture images from the webcam
import java.awt.Rectangle; //A rectangle class which keeps track of the face coordinates.
import processing.serial.*; //The serial library is needed to communicate with the Arduino.
OpenCV opencv; //Create an instance of the OpenCV library.
//Screen Size Parameters
int width = 320;
int height = 240;
// contrast/brightness values
int contrast_value = 0;
int brightness_value = 0;
Serial port; // The serial port
//Variables for keeping track of the current servo positions.
char servoTiltPosition = 90;
char tiltChannel = 0;
//These variables hold the x and y location for the middle of the detected face.
int midFaceY=0;
int midFaceX=0;
//The variables correspond to the middle of the screen, and will be compared to the midFace values
int midScreenY = (height/2);
int midScreenX = (width/2);
int midScreenWindow = 10; //This is the acceptable 'error' for the center of the screen.
//The degree of change that will be applied to the servo each time we update the position.
int stepSize=3;
void setup() {
//Create a window for the sketch.
size( width, height );
opencv = new OpenCV( this );
opencv.capture( width, height ); // open video stream
opencv.cascade( OpenCV.CASCADE_FRONTALFACE_ALT ); // load detection description, here-> front face detection : "haarcascade_frontalface_alt.xml"
println(Serial.list()); // List COM-ports (Use this to figure out which port the Arduino is connected to)
//select first com-port from the list (change the number in the [] if your sketch fails to connect to the Arduino)
port = new Serial(this, Serial.list()[1], 57600); //Baud rate is set to 57600 to match the Arduino baud rate.
//Send the initial pan/tilt angles to the Arduino to set the device up to look straight forward.
port.write(tiltChannel); //Send the Tilt Servo ID
port.write(servoTiltPosition); //Send the Tilt Position (currently 90 degrees)
}
public void stop() {
opencv.stop();
super.stop();
}
void draw() {
// grab a new frame
// and convert to gray
opencv.read();
opencv.convert( GRAY );
opencv.contrast( contrast_value );
opencv.brightness( brightness_value );
// proceed detection
Rectangle[] faces = opencv.detect( 1.2, 2, OpenCV.HAAR_DO_CANNY_PRUNING, 40, 40 );
// display the image
image( opencv.image(), 0, 0 );
// draw face area(s)
noFill();
stroke(255,0,0);
for( int i=0; i<faces.length; i++ ) {
rect( faces[i].x, faces[i].y, faces[i].width, faces[i].height );
}
//Find out if any faces were detected.
if(faces.length > 0){
//If a face was found, find the midpoint of the first face in the frame.
//NOTE: The .x and .y of the face rectangle corresponds to the upper left corner of the rectangle,
// so we manipulate these values to find the midpoint of the rectangle.
midFaceY = faces[0].y + (faces[0].height/2);
midFaceX = faces[0].x + (faces[0].width/2);
//Find out if the Y component of the face is below the middle of the screen.
if(midFaceY < (midScreenY - midScreenWindow)){
if(servoTiltPosition >= 5)servoTiltPosition -= stepSize; //If it is below the middle of the screen, update the tilt position variable to lower the tilt servo.
}
//Find out if the Y component of the face is above the middle of the screen.
else if(midFaceY > (midScreenY + midScreenWindow)){
if(servoTiltPosition <= 175)servoTiltPosition +=stepSize; //Update the tilt position variable to raise the tilt servo.
}
}
//Update the servo positions by sending the serial command to the Arduino.
port.write(tiltChannel); //Send the tilt servo ID
port.write(servoTiltPosition); //Send the updated tilt position.
delay(1);
println (midFaceY);
// println (midScreenY - midScreenWindow);
}

midFaceY goes from 200 to 40 and midScreenY - midScreenWindow is equal to 110. SO what I would like to say is something like:

if(midFaceY < (midScreenY - midScreenWindow)in a time > 900 millis){
if(servoTiltPosition >= 5)servoTiltPosition -= stepSize
}But
if(midFaceY changes from 110 to 40 in a time < 900 millis){
servoTiltPosition == 90;
}

Can Anyone help me please?? I would really appreciate it. As I said before I am learning to do all this by myself and it is really complicate. SO if you can answer me as a really really newbie I will appreciate it more :)

Thanks!!

Replies(3)

PhiLho

Re: OpenCV face detection + Servo and Arduino

1 years ago

I deleted the duplicate message you posted again in the wrong section (Arduino => Hardware).

General hint, as I know nothing about your hardware: use the millis() function to get the time at the start of an event, reuse it at the end, so you can know how many time was spent between.

psica80

Re: OpenCV face detection + Servo and Arduino

1 years ago

ohhh actually this was the wrong section I think.. Is not suppose to be in Programming question??

i have been reading about the millis but i just can't figure how to use it :) As I said I am very new

PhiLho

Re: OpenCV face detection + Servo and Arduino

1 years ago

Yes, think "specialized sections" before going to Programming: nearly all Processing questions are programming questions anyway, but those involving hardware go to this one, those involving a 3rd party library go to Contributed Libraries one, etc.
I am biased as I wrote these articles, but perhaps the http://wiki.processing.org/w/Technical_FAQ can shed a bit more light on these concepts. If not, go back ask questions here...

Note: sometime it is easier for everybody to make a simpler sketch, to explore a concept, an idea, an algorithm, without additional library (if possible) nor involving hardware. Not only it simplifies environment, but people here can run this code and give better advices.

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