gistfile1.py

/*****************************************************************************************
* Name : Fast object tracking using the OpenCV library *
* Author : Lior Chen <chen.lior@gmail.com> *
* Notice : Copyright (c) Jun 2010, Lior Chen, All Rights Reserved *
* : *
* Site : http://www.lirtex.com *
* WebPage : http://www.lirtex.com/robotics/fast-object-tracking-robot-computer-vision *
* : *
* Version : 1.0 *
* Notes : By default this code will open the first connected camera. *
* : In order to change to another camera, change *
* : CvCapture* capture = cvCaptureFromCAM( 0 ); to 1,2,3, etc. *
* : Also, the code is currently configured to tracking RED objects. *
* : This can be changed by changing the hsv_min and hsv_max vectors *
* : *
* License : This program is free software: you can redistribute it and/or modify *
* : it under the terms of the GNU General Public License as published by *
* : the Free Software Foundation, either version 3 of the License, or *
* : (at your option) any later version. *
* : *
* : This program is distributed in the hope that it will be useful, *
* : but WITHOUT ANY WARRANTY; without even the implied warranty of *
* : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* : GNU General Public License for more details. *
* : *
* : You should have received a copy of the GNU General Public License *
* : along with this program. If not, see <http://www.gnu.org/licenses/> *
******************************************************************************************/
#!/usr/bin/python
# -*- coding: utf-8 -*-
from opencv.cv import *
from opencv.highgui import *
from threading import Thread
#import serial

class RobotVision:
cvSize size
cvImage hsv_frame, thresholded, thresholded2
cvScalar hsv_min, hsv_max, hsv_min2, hsv_max2
cvCapture capture;

def InitBallTracking():
globals size, hsv_frame, thresholded, thresholded2, hsv_min, hsv_max, hsv_min2, hsv_max2, capture
print "Initializing ball Tracking"
size = cvSize(640, 480)
hsv_frame = cvCreateImage(size, IPL_DEPTH_8U, 3)
thresholded = cvCreateImage(size, IPL_DEPTH_8U, 1)
thresholded2 = cvCreateImage(size, IPL_DEPTH_8U, 1)

hsv_min = cvScalar(0, 50, 170, 0)
hsv_max = cvScalar(10, 180, 256, 0)
hsv_min2 = cvScalar(170, 50, 170, 0)
hsv_max2 = cvScalar(256, 180, 256, 0)

storage = cvCreateMemStorage(0)

# start capturing form webcam
capture = cvCreateCameraCapture(-1)

if not capture:
print "Could not open webcam"
sys.exit(1)

#CV windows
cvNamedWindow( "Camera", CV_WINDOW_AUTOSIZE );

def TrackBall(i):
t = Thread(target=TrackBallThread, args=(i,))
t.start()

def TrackBallThread(num_of_balls):
globals size, hsv_frame, thresholded, thresholded2, hsv_min, hsv_max, hsv_min2, hsv_max2, capture
while 1:
# get a frame from the webcam
frame = cvQueryFrame(capture)

if frame is not None:

# convert to HSV for color matching
# as hue wraps around, we need to match it in 2 parts and OR together
cvCvtColor(frame, hsv_frame, CV_BGR2HSV)
cvInRangeS(hsv_frame, hsv_min, hsv_max, thresholded)
cvInRangeS(hsv_frame, hsv_min2, hsv_max2, thresholded2)
cvOr(thresholded, thresholded2, thresholded)

# pre-smoothing improves Hough detector
cvSmooth(thresholded, thresholded, CV_GAUSSIAN, 9, 9)
circles = cvHoughCircles(thresholded, storage, CV_HOUGH_GRADIENT, 2, thresholded.height/4, 100, 40, 20, 200)

# find largest circle
maxRadius = 0
x = 0
y = 0
found = False
for i in range(circles.total):
circle = circles[i]
if circle[2] > maxRadius:
found = True
maxRadius = circle[2]
x = circle[0]
y = circle[1]

cvShowImage( "Camera", frame );

if found:
print "ball detected at position:",x, ",", y, " with radius:", maxRadius

if x > 420:
# need to pan right
servoPos += 5
servoPos = min(140, servoPos)
servo(2, servoPos)
elif x < 220:
servoPos -= 5
servoPos = max(40, servoPos)
servo(2, servoPos)
print "servo position:", servoPos
else:
print "no ball"