Is there something similar to polyval for circle fitting?

I am trying to grab tracked objects within a semicircle on the left and right of a vehicle. In the ACC test bed example within multi object tracking documentation on the website, to find a lead vehicle the matlab function uses...

yleftlane = polyval ([curvature, 0, halfLaneWidth], x);

This checks for any car half a lane width to the left within a curved road using the polyval function.

What I want to do is something like this...

yleftcircle = circularfit ([(pi/2)radius^2]); %% find lead vehicle half a circle to the left...

I cant seem to find any circular fitting except for downloaded ones.

Any recommendations or advice?

Answer 1

[Image Analyst]

What's wrong with downloaded functions? I'm attaching one I use, along with a paper for more general purpose one.

[Marshall Botta]

I apologize for the confusion, I may have asked the wrong question. Is there something similar to polynomial evaluation but more like circular evaluation. It seems like this fitting was not the right question to ask. I dont want to make a circle around the points that are already within my camera detection (360 degree FOV), I want to evaluate each point that is detected and tracked and which ever one is more important is the main one I output (lead vehicle).

[Image Analyst]

I have no idea how to determine, in a cluster of several/numerous points, which is "more important" or "the main one." Sorry.