I'm new to Processing and Arduino and trying to to work on face tracking pan and tilt system.
Processing and Arduino to control pan and tilt system with OpenCV and a webcam.
I have found this code online and it seems to work on with built-in Isight webcam, but when I plug in the external webcam, Processing can't seem to recognize the port and I get NullPointerException error.
import gab.opencv.*;
import processing.video.*;
import java.awt.*;
import processing.serial.*; //The serial library is needed to communicate with the Arduino.
Capture video;
OpenCV opencv;
/////////////////////////////////////////////////////////////
//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 servoPanPosition = 90;
//The pan/tilt servo ids for the Arduino serial command interface.
char tiltChannel = 0;
char panChannel = 1;
//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=1;
//////////////////////////////////////////////////
void setup() {
String[] cameras = Capture.list();
size(width, height);
video = new Capture(this, width/2, height/2, cameras[0]);
opencv = new OpenCV(this, width/2, height/2);
opencv.loadCascade(OpenCV.CASCADE_FRONTALFACE);
video.start();
////////////////////////////////////////////////////
port = new Serial(this, "/dev/tty.usbmodem411", 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)
port.write(panChannel); //Send the Pan Servo ID
port.write(servoPanPosition); //Send the Pan Position (currently 90 degrees)
/////////////////////////////
}
void draw() {
scale(2);
opencv.loadImage(video);
image(video, 0, 0 );
noFill();
stroke(0, 255, 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);
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.
}
//Find out if the X component of the face is to the left of the middle of the screen.
if(midFaceX < (midScreenX - midScreenWindow)){
if(servoPanPosition >= 5)servoPanPosition -= stepSize; //Update the pan position variable to move the servo to the left.
}
//Find out if the X component of the face is to the right of the middle of the screen.
else if(midFaceX > (midScreenX + midScreenWindow)){
if(servoPanPosition <= 175)servoPanPosition +=stepSize; //Update the pan position variable to move the servo to the right.
}
}
//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.
port.write(panChannel); //Send the Pan servo ID
port.write(servoPanPosition); //Send the updated pan position.
if(faces.length == 0){
servoTiltPosition = 90;
servoPanPosition = 90;
}
//delay(1);
}
void captureEvent(Capture c) {
c.read();
}
Moderator edit:
</mark> <mark>[code]</mark> <mark>
</mark> <mark>[/code]</mark> <mark>
tags added.
servo_face_detect.ino (1.51 KB)
my_face_detection1.pde (4.37 KB)