Motion detection

Motion distances X, Y.

These parameters specify the threshold distances (horizontal and vertical) between two detected spots from two adjacent frames. If these spots are closer than the threshold, then the pair (and the subsequent spots, if any) will be identified as a moving object.
The history of the spot's motion can have single missing frames, where the spot was not detected.
The distance are specified as a percentage of the frame size.
Set these distances smaller if you often have two spots from two subsequent frames that appear rather close to each other. This will make the spot removal easier.
Set them higher if you process cartoons and expect to have high motion scenes.

Motion table size X, Y.

Motion table is an additional mechanism that prevents the removal of spots being parts of moving objects. The spot removal is inhibited in areas of the image with a fast variation of the average intensity.
The frame is divided on a table of cells with X columns and Y rows, and the average intensity in each cell is monitored in time.
The motion table can have no more than 24 columns and 18 rows.

Motion table threshold.

If the change of the average intensity in a cell of the motion table exceeds this threshold then that cell is flagged as a cell with motion, and all spots in that cell will be ignored (i.e. not removed).
Set it higher to reduce motion sensitivity and remove more spots.