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Passing argument to a function

Hello experts!

Have a look at my source code.

Two questions if I may:

1. How can I pass argument to this function when debugging using VC++
2. How can I pass argument to this function when running using console?

Thank you!

panJames

 
#include <cv.h>
#include <highgui.h>
#include <math.h>

using namespace cv;

int main(int argc, char** argv)
{
    Mat src, dst, color_dst;
    if( argc != 2 || !(src=imread(argv[1], 0)).data)
        return -1;

    Canny( src, dst, 50, 200, 3 );
    cvtColor( dst, color_dst, CV_GRAY2BGR );


    vector<Vec4i> lines;
    HoughLinesP( dst, lines, 1, CV_PI/180, 80, 30, 10 );
    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;

}

Open in new window

#include <cv.h>
#include <highgui.h>
#include <math.h>

using namespace cv;

int main(int argc, char** argv)
{
    Mat src, dst, color_dst;
    if( argc != 2 || !(src=imread(argv[1], 0)).data)
        return -1;

    Canny( src, dst, 50, 200, 3 );
    cvtColor( dst, color_dst, CV_GRAY2BGR );


    vector<Vec4i> lines;
    HoughLinesP( dst, lines, 1, CV_PI/180, 80, 30, 10 );
    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;

}

Open in new window

0
panJames
Asked:
panJames
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2 Solutions
 
jkrCommented:
Well what kind of argument do you want to pass to which function in the above?
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Infinity08Commented:
Both programs seem to accept an image filename is the one and only argument, so you could call it like this eg. :

        my_application.exe my_image.ext
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panJamesAuthor Commented:
According to website I took example from:

http://opencv.willowgarage.com/documentation/cpp/feature_detection.html?highlight=hough#HoughLinesP

it should be file name.

/* This is a standalone program. Pass an image name as a first parameter
of the program. */

For me it looks like integer should be first...

panJames
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Infinity08Commented:
>> For me it looks like integer should be first...

argv[0] is the executable name
argv[1] is the first parameter

argc contains the amount of items in the argv array (including the executable name)

So the (argc != 2) check makes sure that  argc is equal to 2 (the executable name plus one parameter), and the one parameter is then passed to the imread function.
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jkrCommented:
Well, your call

HoughLinesP( dst, lines, 1, CV_PI/180, 80, 30, 10 );

pretty much matches the declaration:

void HoughLinesP(Mat& image, vector<Vec4i>& lines, double rho, double theta, int threshold, double minLineLength=0, double maxLineGap=0);

except that you are passing integers instead of doubles, so that should rather be

HoughLinesP( dst, lines, 1.0, CV_PI/180.0, 80.0, 30.0, 10.0 );
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panJamesAuthor Commented:
To Infinity08

I typed in console as you said:

  my_application.exe my_image.ext

And it works fine!

Two questions though:

1. In my main function

int main(int argc, char** argv)

first argument argc is integer, why don't I actually pass it?

2. How can I pass my arguments to main in VC++ for checking how it works during debuggin?

panJames



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Infinity08Commented:
>> first argument argc is integer, why don't I actually pass it?

The operating system takes care of that for you. All the parameters you pass on the command line will be placed in the argv array, and argc will contain the amount of items in that array.


>> 2. How can I pass my arguments to main in VC++ for checking how it works during debuggin?

I'll leave this one for someone who actually uses VC++. But there should be an option to set the command line arguments for debugging. jkr ?
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jkrCommented:
You can enter your arguments in the Project Settings, category 'Debug'.
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