X, Y values

Hello everybody, I just got my open MV M7 and I’m getting the hang of it.

With that said, I’m using it to scan a 10x10 data matrix, it does this with ease, really great. I’m having a problem with I need to be able to tell how far from the center of the camera the matrix
is off center.

So far, I’m unable to solve this issue. I need to put out the serial port the values of x, y how far it’s off, I looked at the find circles which does provide x, y, r values But I must admit I’m at a loss as how to go about adding this to my project.

#for c in img.find_circles(threshold = 2000, x_margin = 10, y_margin = 10, r_margin = 10):

img.draw_circle(c.x(), c.y(), c.r(), color = (255, 0, 0))


How can this be done in the 10x10 library?

I do write a lot of firmware for micro controllers and computers but it’s all in basic, I’m not new to python but not great at it… I really need some help on this one,

Thanks for any help you can provide

Hi, if you have a 10x10 data matrix then you should have a returned ROI for it. I.e. x/y/w/h.

So the center of that is:

cx = x + (w / 2)
cy = y + (h / 2)

Then if you want to know the difference from the center of the image…


xoff = (img.width() / 2) - cx
yoff = (img.height() / 2) - cy

This works as long as the image is not rotated. If it’s rotated then you have to get the centroid of the 4 corners. This is easy though too. The centroid of the 4 corners is the sum of all x positions divided by 4 for x and the sum of all y positions divided by 4 for y. I believe the rotation of the data matrix is a returned attribute so you can use that to determine if it’s not straight.

Hello there,

Thank-you for the help, Now I know I’m a newbie when I ask this question.

What is a ROI, and where do I find it?

I ended up trying out : print(“N”,matrix.payload(),“X”,matrix.x(),“Y”,matrix.y(),“R”,matrix.rotation())

So, this does show the returned information in the serial area, now I’ll just do the math on it and it should be good to go.



Hey thank you for that link in the above post, that is a lot of unknown information that I did not know about :slight_smile:

Also that link leads to a lot more information that I need.

My hats off to you kind sir,