Digitising RH/T charts

We have some years of relative humidity paper charts whose data
should be integrated with the modern electronic systems.  Digitising
(at least semi-automatically) would be better than manually
transcribing the points into a spreadsheet.

A number of different thermohygrographs, drum and circular, were
used with various sizes of chart and colours of line.  There are the
normal problems of charts running overtime and being over written,
running faint etc.

Both rectangular and circular charts have curved axes.  The lines
will need to be converted from X,Y coordinates to Time/RH and Temp
values. Has anyone developed algorithms and a system for capturing
these data?

Velson Horie
Research Project Manager
Collection Care
British Library


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                  Conservation DistList Instance 21:7
                   Distributed: Monday, May 28, 2007
                        Message Id: cdl-21-7-017
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