We are not a member of the ECHOPHYSIOLOGY list but we would like to
send the following message to the list subscribers to complement Dr. Jim
Stewart recent request on needle measurement systems. We tried
Regarding Dr. Jim Stewart request on leaf area measurmeent systems:
1-Accuracy must be considered. It is a good idea to calibrate scanners to
compensate for differences they might have in the dpi they pretend to scan
and the real dpi they do.
2- Speed is also an issue. Speed gains can be done in software, which can
be optimized to the cyclic nature of measurement and data saving, and also
in hardware by simple accessories that allow to place the needles to scan
at specific places on the scanner. This allow to bypass the "preview" step.
3-Regarding costs: Scanners with proper dual lighting systems that avoid
the shadow problem of needles are available for 500$us or less. This make
any in-house design more expensive (unless people are willing to work for
The Mac/WinNEEDLE software and system is less expensive than many people think.
One suggestion: prices can be cheaper if people form a group for buying.
Any manufacturer or seller is sensitive to group buying.
Training cost must also be considered. Complex softwares require more
training for the operators.
Finally I'd like to say that needle measurement is slightly more than
"simply counting dots".
See our web site http://www.regent.qc.ca for more info (much more is
REGENT INSTRUMENTS INC.
165 Fatima Ave.
regent at regent.qc.ca
sales at regent.qc.ca