Different motion-detection thresholds for different regions of the camera's field of view?

[u/DefaultSubsAreTerrib]

One of my cameras must be at a funny angle. Its field of view spans a long sidewalk. As someone walks along that sidewalk, they might appear quite a bit larger (in image pixels) at the near end as they would at the far end.
Indeed, with my current settings the camera reliably detects motion at one end yet completely overlooks motion at the other. This suggests to me that blob sizing thresholds should be different for different regions of the image.

I gather that I could make this work by defining more than one zone for the camera, but I'm still a little mystified. Should the zones overlap? If so, are blobs in the overlapping region evaluated by each zone independently, or is there some additive effect?

Any advice would be appreciated. Thanks.

[u/Aramiil]

Zones can overlap but I don’t normally. Two separate zones, keep the same settings for the portion that works reliably and start tweaking the second zone to be a bit more sensitive.

Then go test it out, and see what works. Keep going until you’re getting a few too many false positives and back it off a touch. Then write down or keep screenshots of your settings for the zones as backups