Depending on the filament surface and moving speed, the PAT9125 sensor
can stop being able to track movement.
In such cases, instead of triggering false errors and/or relying on
previous states, read and use the exposure data off the sensor and
increase error counts only for poorly exposed images instead, which
is a good indicator of a far-away (or missing!) tracking surface.
Yuri D'Elia
Marek Bel
Robert Pelnar