Image analysis

Hi, I have a rather interesting image processing task to be solved. What I need: I will need a little app that works on Windows to calculate the below task and I want to feed this app with a vector image to make some length calculations on it. Or I guess it could be done with Matlab? Please have a look at the image first. It's a disc brake rotor outline drawing (with some circles on it). As you can see a disc rotor has some holes in the braking track surface. I want to calculate the length of braking surface, excluding those holes, at a given radius (radius calculated from the geometric center of the disc rotor). To be more precise: I have drawn some lines for you to understand it better. Those blue circular lines represent the calculation paths. First circle has 130 mm diameter, last one 160 mm diameter. And they increase by 1 mm. I need to know at every of those circles what is the length of the path without the holes. To make it easier to understand I drew red line. As you can see, it's broken line. It's broken as I only need to know the total length of that red line on the given circumference. The gaps without the red line is where the holes are. So if the rotor would have no holes the path length would simply be the length of that circle. The Software: *New app or if possible script in Matlab? *I would prefer to load vector image like DWG format or any other vector format. Recognizing the center of the rotor: I can provide a single point on the image for you. Recognizing the holes: In general every hole has a closed path, but on the extremes the path will not be close (imagine depression on the edge of the rotor - it's not closed path in a sense) So if this would be a problem then perhaps I could highlight holes manually on the image in that little software somehow Idea is to make the designs, then load them to this software and see the calculation.