What if we do not predict s and h

[Jensen-Su]

I wonder if the model can fit a polyline x = a * y**3 + b * y ** 2 + c * y + d without fitting offset s and horizontal line h, since the problem seems to be poor-formed.

Intuitively, at point y = 100pix, the equation would be x = a * 1000000 + b * 10000 + c * 100 + d. A tiny perturbation on a would introduce a dramatic change in x, which makes it too hard to learn the other parameters b, c, d, especially the offset parameter d.

So what are the important points that make the model successfully fit a polyline?

[lucastabelini]

I am not sure that I follow. How would you know the limits of the polyline?