LDTC(tmp2 ≥ 16) detects only crosswise,
LDTC(tmp2 ≥ 32) detects only diagonally,
LDTC (tmp2 ≥ 64) indicates the distance of the detected pixel as a FILT ctype.
These are used to line up LDTC and FILT.
For suggestions 1 and 2, placing a conductor opposite the direction you want to detect causes LDTC to only detect particles in that direction.