Lx=1280; Ly=960; F=8; 
Lx2=int(Lx/F); Ly2=int(Ly/F)
Ly21=Ly2-1
X1=int(Lx2/8); X2=X1*2; X3=X1*3; X4=X1*4; 
X5=X1*5; X6=X1*6; X7=X1*7
XX1=X1*F; XX2=X2*F
XL=X3; XR=X5; 
image_size=128
isz=image_size