TRDB-LTM touch screen problem with coordinates

hello,

i'm trying to to understand the coordinates i'm receiving from the screen.i'm working in differential mode and 8 bit conversion.

the coordinates that i'm getting is as follows (X,Y):

upper left corner : (13,117)

upper right corner : (108,144)

bottom left corner : (9,92)

bottom right corner : (56,24)

what i'm getting is far from a square shape of the screen.

i need to convert it to 160X120 resolution.

any ideas what to do?