In order to develop a system robust to global shape vari-
ations, we extract features from local zones of the signature
image. For this, the image is either divided into zones using
a fixed number of rectangular grids in Cartesian coordinates
or using a circular tessellation around the origin point in po-
lar coordinates. A sample signature, overlaid with a 10x20
rectangular grid is shown in Figure
1
where the signature is
padded with space (shown in gray) to make it fit the grid.
An example of the polar grid where the origin is selected as
the centroid of the signature is shown in Figure
2
.Thesize
of rectangular grid is selected as 10x20, whereas the num-
ber of angular bins used in the polar system is selected as
12, and that of distance bins is selected as 15. Grid sizes are
found experimentally on a separate validation set, though in
future it might be better to use bigger zones for space and
time efficiency