3. INTRODUCTION
Fax machines became popular around the
world in the 1980s.
In order to reduce paper consumption we
use paperless fax machine.
In this paperless fax machine single-touch
panel is used as input and output device.
4. Transmitted and received fax documents are
stored in memory.
A pressure sensitive stylus is used to write
on the touch panel.
Handwriting reconstruction algorithm is
used.
6. The modem module for sending and receiving
faxes.
The touch panel displays the fax documents and
accepts the handwriting signatures.
The tip of the pressure sensitive stylus is
connected to a pressure sensor through a spring
coil.
During a signing act, the pressure at the tip is
measured, digitalized by an ADC, and finally sent
to MCU for subsequent processing.
7. OPERATING PROCEDURES
The touch panel fax machine can operate in one
of the three modes:
1. Fax receiving mode
2. Browsing and handwriting mode
3. Fax transmitting mode
8. HANDWRITING
RECONSTRUCTION
The handwriting reconstruction algorithm, turn an
user’s signing act into a digital signature as close
to the original as possible.
During the signing act, the data from the pressure
sensitive stylus and the touch panel are sampled
by using timer interrupts in MCU.
9. The sampled analog
values are then converted
into digital values by
ADCs and buffered in two
FIFO queues in order as
shown in figure.
10. Some issues that are considered in data
collection and processing.
1. Resolution of touch panel
2. Signal synchronization
3. Pressure and Strokes
4. Handwriting Reconstruction
11. Resolution of touch panels:
A single-touch panel is composed of two major parts,
an LCD screen for displaying and a thin touch layer
for inputs.
The resolution of an LCD screen is specified explicitly
by enumerating the number of pixels both in width
and height.
The resolution of the touch panel is determined by
the number of bits used in the ADCs adopted.
12. Signal synchronization:
Single-touch panels can response exact one location
that is being touched at a time.
Timer interrupt intervals are made set to be constant.
According to changes in the pressure data measured,
handwriting reconstruction algorithm can generate the
strokes with different thickness.
13. Pressure and Strokes:
A simple two-step calibration
procedure for the stylus is
performed before writing.
First, press the pen tip all the way
down and record the pressure
reading as PF .
Next, let the tip off the touch panel
and record the pressure again as
PE.
For any pressure P, the pressure
ratio(PR) is calculated as
PR=(P-PE)/(PF-PE)
17. CONCLUSION
By using handwriting reconstruction algorithm the
signature can be exactly reproduced.
Consumption of paper can be reduced.
18. REFERENCES
• http://ieee.ieeexplore.org/
• ITU-T.37: Procedures for the Transfer of Facsimile Data via
Store-and forward on the Internet, 1998.
• ITU-T.38: Procedures for Real-time Group 3 Facsimile
Communication over IP Networks, Amendment 1, 1999.
• Handwriting Recognition Group, <hwr.nici.kun.nl>, May,
2008.