Vivek Goel's profile - activity

Ok, i should try it again with proper structuring element. Thanks

Will canny give edges of different thickness? Since if the canny output give edges of different thickness then it will be correct solution but if the detected edges are of same thickness then the morphological operations will be much hard to calibrate and I will to design a much good and sophisticated structuring element.

Since all the edges are of same thickness it doesn't matter what I should use first opening or closing. I want to use the parameters in Hough P Transform to eliminate redundant lines.

Actually if I will use morphological operations, the edges on which I have to work will be lost! Since they are of same thickness.

ya it's good to use morphological operations but HoughP transform already have parameters to do this. Can you tell me the working and use of last 2 parameters in which i have given 600 and 300 value?

for hough line code is -: HoughLinesP(dst,lines,1,CV_PI/180,80,30,10); now make a conditional statement like-:

if( theta>CV_PI/180*170 || theta<CV_PI/180*10)
    { Point pt1, pt2;
    ..........
    line( cdst, pt1, pt2, Scalar(0,0,255), 3, CV_AA);
    }

this while restrict the scope of detected lines and then you will be able to show your horizontal lines only.

After increasing the minLineLength and decreasing maxLineGap program is still showing number of lines and also the gap is also visible. Can someone tell me the problem in the program? Image is:- Code is-:

include "stdafx.h"

include <cv.h>
include <highgui.h>
include <math.h>
using namespace cv;
int main(int argc, char** argv)
{
    Mat src, dst, color_dst;
    src = imread("line2.jpg", 0);
    Canny(src, dst, 50, 200, 3);
    cvtColor(dst, color_dst, CV_GRAY2BGR);


    vector<Vec4i> lines;
    HoughLinesP(dst,lines,1,CV_PI/180,80,600,300);
    for (size_t i = 0; i < lines.size(); i++)
    {
        line(color_dst, Point(lines[i][0], lines[i][1]),
            Point(lines[i][2], lines[i][3]), Scalar(0, 0, 255), 3, 8);
    }
    namedWindow("Source", 1);
    imshow("Source", src);
    namedWindow("Detected Lines", 1);
    imshow("Detected Lines", color_dst);
    waitKey(0);
    return(0);
}

No issue :) Hitting hard make you stronger. And yes i asked new question. My apology.

Applied hough line transform. How can I find orientation of the detected line? Firstly:-

1. I do thresholding.
2. Applied Hough Line transform.
3. For orientation I tried traversing the image, then find two set of points (x1,y1) and (x2,y2) from where the change in colour due to hough line transform take place in two different levels.
4. Find points to get the slope between them.

But the program become very complex with no result.

Did that :(

Sorry Sir, I had read the faq and I had also tried the code of this problem but after many effort I failed, I want to start with scratch. So therefore I ask this type of question.

There is no issue in giving command. But I am not getting the algorithm how to find orientation.

I mean algorithm or functions I should use. I want to make my bot work and walk using line following.

So in shadow or in change in environment like in water it will be pretty useful and efficient?

i also need to know that which color space is more efficient in calibrating and detection of colors in live video.

it is just exiting with code 0. the console opens and close in 1 second in many programs.

through your motivation i will definitely try it in future. i am getting some problem with my webcam, i will check it out soon and contact you later :)

#include "stdafx.h"
#include <stdio.h>
#include <highgui.h>
#include <cv.h>
#include <cxcore.h>

void main(){ //Sobel edge detection for a video

    CvCapture* capture = cvCreateCameraCapture(0);  //The video is loaded into a pointer of type CvCapture
    IplImage* frame; IplImage*gscale_res; IplImage* edgeframe; //Declaration of structure variables to store frames
    char *win = "video"; char *winEdge = "edges"; //Declaration of character pointers to store window names
    cvNamedWindow(win, CV_WINDOW_AUTOSIZE); //Window is created for original image
    cvNamedWindow(winEdge, CV_WINDOW_AUTOSIZE); //Window is created for resultant image

    while (1)
    {
        frame = cvQueryFrame(capture); //Image under consideration is captured as a shot of the video
        if (!frame)
        {
            printf("cam not found");
            break;
        }
        gscale_res = cvCreateImage(cvSize(frame->width, frame->height), IPL_DEPTH_8U, 1);//Creation of the image variable to store both the grayscale intermediate and final result
        edgeframe = cvCreateImage(cvSize(frame->width, frame->height), IPL_DEPTH_16S, 1); //The 16-bit signed image for the result of the Sobel Edge detection
        cvCvtColor(frame, gscale_res, CV_BGR2GRAY); //Gray-scale intermediate created
        cvSobel(gscale_res, edgeframe, 1, 0, 3);// Sobel edge detection function is applied on the grayscale image and the result is put in the other variable
        cvConvertScaleAbs(edgeframe, gscale_res, 1, 0); //The 16-bit signed image is converted to an 8-bit unsigned version so it can be displayed
        cvShowImage(win, frame); //Original image is shown
        cvShowImage(winEdge, gscale_res); //Resultant image with edges detected, is shown
        char c = cvWaitKey(33); //This is to account for the frame speed of the loaded video
        cvReleaseImage(&gscale_res);
        cvReleaseImage(&edgeframe);
        if (c == 27) //If the character of code 27 or the ESCAPE character is entered, the loop will break
            break;
    }

    cvReleaseCapture(&capture); //Video is released from memory
    cvReleaseImage(&frame);  //Images released from memory
    cvDestroyWindow(win);
    cvDestroyWindow(winEdge); //Windows closed
}

i have tried different arguments, cvCreateCameraCapture,cvCaptureFromCAM but still not working

flood of errors..

thanks for your presence. it will be gratefull if you would take a llok at the above code if you have free time later. thanks alot. :)

how can i learn the c++ interface? means if want to to start learning it.

i am using the same. can you send me a code for color detection.? i can check for that.

so what should be the problem. why it is not working? when i am capturing a video, it works fine. :/

now in console it's showing 'Null frame press any key to continue...' and than exits

its showing only a console for only 5 secs and exits.

but it is exiting in my pc. without opening windows and all.

help me, how to fix it. it will be very thankfull.

ok, thanks and also sorry brother :) i am budding user so did some mistakes. i will reply with full specifications later because as of now i can't disclose it.

I am try to run the code but msv execution is exiting and sometimes it shows breakpoint error. P.S. code is copied.

#include "stdafx.h"
#include "opencv/cvaux.h"
#include "opencv/highgui.h"
#include "opencv/cxcore.h"
#include <stdio.h>

int main(int argc, char* argv[])
{
    CvCapture* camera = cvCreateCameraCapture(-1); // Use the default camera

    IplImage* frame = 0;
    CvMemStorage* storage = cvCreateMemStorage(0); //needed for Hough circles

    // capturing some extra frames seems to help stability
    frame = cvQueryFrame(camera);
    frame = cvQueryFrame(camera);
    frame = cvQueryFrame(camera);

    // with default driver, PSEye is 640 x 480
    CvSize size = cvSize(640, 480);
    IplImage *  hsv_frame = cvCreateImage(size, IPL_DEPTH_8U, 3);
    IplImage*  thresholded = cvCreateImage(size, IPL_DEPTH_8U, 1);
    IplImage*  thresholded2 = cvCreateImage(size, IPL_DEPTH_8U, 1);

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

    //do {
    frame = cvQueryFrame(camera);
    if (frame != NULL) {
        printf("got frame\n\r");
        // color detection using HSV
        cvCvtColor(frame, hsv_frame, CV_BGR2HSV);
        // to handle color wrap-around, two halves are detected and combined
        cvInRangeS(hsv_frame, hsv_min, hsv_max, thresholded);
        cvInRangeS(hsv_frame, hsv_min2, hsv_max2, thresholded2);
        cvOr(thresholded, thresholded2, thresholded);

        cvSaveImage("thresholded.jpg", thresholded);

        // hough detector works better with some smoothing of the image
        cvSmooth(thresholded, thresholded, CV_GAUSSIAN, 9, 9);
        CvSeq* circles = cvHoughCircles(thresholded, storage, CV_HOUGH_GRADIENT, 2, thresholded->height / 4, 100, 40, 20, 200);

        for (int i = 0; i < circles->total; i++)
        {
            float* p = (float*)cvGetSeqElem(circles, i);
            printf("Ball! x=%f y=%f r=%f\n\r", p[0], p[1], p[2]);
            cvCircle(frame, cvPoint(cvRound(p[0]), cvRound(p[1])),
                3, CV_RGB(0, 255, 0), -1, 8, 0);
            cvCircle(frame, cvPoint(cvRound(p[0]), cvRound(p[1])),
                cvRound(p[2]), CV_RGB(255, 0, 0), 3, 8, 0);
        }

        cvSaveImage("frame.jpg", frame);
    }
    else {
        printf("Null frame\n\r");
    }
    //} while (true);
    cvReleaseCapture(&camera);
    return 0;
}

and errors are..

The thread 0x1cbc has exited with code 0 (0x0).
The thread 0xe84 has exited with code 0 (0x0).
The thread 0x1ec4 has exited with code 0 (0x0).
The thread 0x1590 has exited with code 0 (0x0).
The thread 0x11f8 has exited with code 0 (0x0).
The thread 0x1e04 has exited with code 0 (0x0).
The thread 0x1404 has exited with code 0 (0x0).
The program '[32] Myhello2.exe' has exited with code 0 (0x0).

I am usimg arduino omega for motor drivers and other peripherals and panda board for calibration. you can see the task on auvsi.

sir, i am currently working on an AUV, but there is delay in imgae processed by it. How the proformance can be improved. answers will be appreciated.