I have a school project I've been working on, and to do so I've been using Kyle Hounslow's real-time motion tracking with color tutorial. Link: (https://www.youtube.com/watch?v=bSeFrPrqZ2A) and so far I've filtered out my specific color (blue) and have been able to track it consistently.
What I need to know is how to draw a line and add a function to it, so that when my specified contour collides with that line, it activates triggers an action I plan on integrating in the future. I know little next to nothing about C++ so if someone could explain it to me I would find that very helpful. Thanks.
Here is my code so far:
(https://dl.dropboxusercontent.com/u/28096936/tuts/objectTrackingTut.cpp)(https://dl.dropboxusercontent.com/u/28096936/tuts/objectTrackingTut.cpp)
Full code:
//objectTrackingTutorial.cpp
//Written by Kyle Hounslow 2013
//Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software")
//, to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
//and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
//The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
//IN THE SOFTWARE.
include <sstream>
include <string>
include <iostream>
include <opencv\highgui.h>
include <opencv\cv.h>
using namespace cv;
//initial min and max HSV filter values.
//these will be changed using trackbars
int H_MIN = 0;
int H_MAX = 256;
int S_MIN = 0;
int S_MAX = 256;
int V_MIN = 0;
int V_MAX = 256;
//default capture width and height
const int FRAME_WIDTH = 640;
const int FRAME_HEIGHT = 480;
//max number of objects to be detected in frame
const int MAX_NUM_OBJECTS=50;
//minimum and maximum object area
const int MIN_OBJECT_AREA = 2020;
const int MAX_OBJECT_AREA = FRAME_HEIGHTFRAME_WIDTH/1.5;
//names that will appear at the top of each window
const string windowName = "Original Image";
const string windowName1 = "HSV Image";
const string windowName2 = "Thresholded Image";
const string windowName3 = "After Morphological Operations";
const string trackbarWindowName = "Trackbars";
void on_trackbar( int, void* )
{//This function gets called whenever a
// trackbar position is changed
}
string intToString(int number){
std::stringstream ss;
ss << number;
return ss.str();
}
void createTrackbars(){
//create window for trackbars
namedWindow(trackbarWindowName,0);
//create memory to store trackbar name on window
char TrackbarName[50];
sprintf( TrackbarName, "H_MIN", H_MIN);
sprintf( TrackbarName, "H_MAX", H_MAX);
sprintf( TrackbarName, "S_MIN", S_MIN);
sprintf( TrackbarName, "S_MAX", S_MAX);
sprintf( TrackbarName, "V_MIN", V_MIN);
sprintf( TrackbarName, "V_MAX", V_MAX);
//create trackbars and insert them into window
//3 parameters are: the address of the variable that is changing when the trackbar is moved(eg.H_LOW),
//the max value the trackbar can move (eg. H_HIGH),
//and the function that is called whenever the trackbar is moved(eg. on_trackbar)
// ----> ----> ---->
createTrackbar( "H_MIN", trackbarWindowName, &H_MIN, H_MAX, on_trackbar );
createTrackbar( "H_MAX", trackbarWindowName, &H_MAX, H_MAX, on_trackbar );
createTrackbar( "S_MIN", trackbarWindowName, &S_MIN, S_MAX, on_trackbar );
createTrackbar( "S_MAX", trackbarWindowName, &S_MAX, S_MAX, on_trackbar );
createTrackbar( "V_MIN", trackbarWindowName, &V_MIN, V_MAX, on_trackbar );
createTrackbar( "V_MAX", trackbarWindowName, &V_MAX, V_MAX, on_trackbar );
}
void drawObject(int x, int y,Mat &frame){
//use some of the openCV drawing functions to draw crosshairs
//on your tracked image!
//UPDATE:JUNE 18TH, 2013
//added 'if' and 'else' statements to prevent
//memory errors from writing off the screen (ie. (-25,-25) is not within the window!)
circle(frame,Point(x,y),20,Scalar(0,255,0),2);
if(y-25>0)
line(frame,Point(x,y),Point(x,y-25),Scalar(0,255,0),2);
else line(frame,Point(x,y),Point(x,0),Scalar(0,255,0),2);
if(y+25<FRAME_HEIGHT)
line(frame,Point(x,y),Point(x,y+25),Scalar(0,255,0),2);
else line(frame,Point(x,y),Point(x,FRAME_HEIGHT),Scalar(0,255,0),2);
if(x-25>0)
line(frame,Point(x,y),Point(x-25,y),Scalar(0,255,0),2);
else line(frame,Point(x,y),Point(0,y),Scalar(0,255,0),2);
if(x+25<FRAME_WIDTH)
line(frame,Point(x,y),Point(x+25,y),Scalar(0,255,0),2);
else line(frame,Point(x,y),Point(FRAME_WIDTH,y),Scalar(0,255,0),2);
putText(frame,intToString(x)+","+intToString(y),Point(x,y+30),1,1,Scalar(0,255,0),2);
}
void morphOps(Mat &thresh){
//create structuring element that will be used to "dilate" and "erode" image.
//the element chosen here is a 3px by 3px rectangle
Mat erodeElement = getStructuringElement( MORPH_RECT,Size(3,3));
//dilate with larger element so make sure object is nicely visible
Mat dilateElement = getStructuringElement( MORPH_RECT,Size(8,8));
erode(thresh,thresh,erodeElement);
erode(thresh,thresh,erodeElement);
dilate(thresh,thresh,dilateElement);
dilate(thresh,thresh,dilateElement);
}
void trackFilteredObject(int &x, int &y, Mat threshold, Mat &cameraFeed){
Mat temp;
threshold.copyTo(temp);
//these two vectors needed for output of findContours
vector< vector<Point> > contours;
vector<Vec4i> hierarchy;
//find contours of filtered image using openCV findContours function
findContours(temp,contours,hierarchy,CV_RETR_CCOMP,CV_CHAIN_APPROX_SIMPLE );
//use moments method to find our filtered object
double refArea = 0;
bool objectFound = false;
if (hierarchy.size() > 0) {
int numObjects = hierarchy.size();
//if number of objects greater than MAX_NUM_OBJECTS we have a noisy filter
if(numObjects<MAX_NUM_OBJECTS){
for (int index = 0; index >= 0; index = hierarchy[index][0]) {
Moments moment = moments((cv::Mat)contours[index]);
double area = moment.m00;
//if the area is less than 20 px by 20px then it is probably just noise
//if the area is the same as the 3/2 of the image size, probably just a bad filter
//we only want the object with the largest area so we safe a reference area each
//iteration and compare it to the area in the next iteration.
if(area>MIN_OBJECT_AREA && area<MAX_OBJECT_AREA && area>refArea){
x = moment.m10/area;
y = moment.m01/area;
objectFound = true;
refArea = area;
}else objectFound = false;
}
//let user know you found an object
if(objectFound ==true){
putText(cameraFeed,"Tracking Object",Point(0,50),2,1,Scalar(0,255,0),2);
//draw object location on screen
drawObject(x,y,cameraFeed);}
}else putText(cameraFeed,"TOO MUCH NOISE! ADJUST FILTER",Point(0,50),1,2,Scalar(0,0,255),2);
}
}
int main(int argc, char* argv[])
{
//some boolean variables for different functionality within this
//program
bool trackObjects = false;
bool useMorphOps = false;
//Matrix to store each frame of the webcam feed
Mat cameraFeed;
//matrix storage for HSV image
Mat HSV;
//matrix storage for binary threshold image
Mat threshold;
//x and y values for the location of the object
int x=0, y=0;
//create slider bars for HSV filtering
createTrackbars();
//video capture object to acquire webcam feed
VideoCapture capture;
//open capture object at location zero (default location for webcam)
capture.open(0);
//set height and width of capture frame
capture.set(CV_CAP_PROP_FRAME_WIDTH,FRAME_WIDTH);
capture.set(CV_CAP_PROP_FRAME_HEIGHT,FRAME_HEIGHT);
//start an infinite loop where webcam feed is copied to cameraFeed matrix
//all of our operations will be performed within this loop
while(1){
//store image to matrix
capture.read(cameraFeed);
//convert frame from BGR to HSV colorspace
cvtColor(cameraFeed,HSV,COLOR_BGR2HSV);
//filter HSV image between values and store filtered image to
//threshold matrix
inRange(HSV,Scalar(H_MIN,S_MIN,V_MIN),Scalar(H_MAX,S_MAX,V_MAX),threshold);
//perform morphological operations on thresholded image to eliminate noise
//and emphasize the filtered object(s)
if(useMorphOps)
morphOps(threshold);
//pass in thresholded frame to our object tracking function
//this function will return the x and y coordinates of the
//filtered object
if(trackObjects)
trackFilteredObject(x,y,threshold,cameraFeed);
//show frames
imshow(windowName2,threshold);
imshow(windowName,cameraFeed);
imshow(windowName1,HSV);
//delay 30ms so that screen can refresh.
//image will not appear without this waitKey() command
waitKey(30);
}
return 0;
}
Windows 7, 32 bit, Microsoft Visual Studio 2010, C++
