HVS color space in Open CV

Question

I am going to detect a yellow color object when i open up my System CAM using Open CV programming, i got some help from the tutorial Object Recognition in Open CV but i am not clear about this line of code, what it does, i don't know. please elaborate me on the below line of code, which i am using.

cvInRangeS(imgHSV, cvScalar(20, 100, 100), cvScalar(30, 255, 255), imgThreshed);

other part of program:

CvMoments *moments = (CvMoments*)malloc(sizeof(CvMoments));
    cvMoments(imgYellowThresh, moments, 1);

    // The actual moment values
    double moment10 = cvGetSpatialMoment(moments, 1, 0);
    double moment01 = cvGetSpatialMoment(moments, 0, 1);
    double area = cvGetCentralMoment(moments, 0, 0);

Answer 1

What about reading documentation?

inRange:

Checks if array elements lie between the elements of two other arrays.

And actually that article contains clear explanation:

And the two cvScalars represent the lower and upper bound of values that are yellowish in colour.

About second code. From that calculations author finds center of object and its square. Quote from article:

You first allocate memory to the moments structure, and then you calculate the various moments. And then using the moments structure, you calculate the two first order moments (moment10 and moment01) and the zeroth order moment (area).

Dividing moment10 by area gives the X coordinate of the yellow ball, and similarly, dividing moment01 by area gives the Y coordinate.