Wednesday, November 4, 2009 Convention Center, Exhibit Hall BC,
Second Floor One difficulty in the routine analysis of fine root
diameter response to environmental stimuli is the lack of
scanners with resolutions above 189 p mm-1 (4800 dpi). A 10%
change in diameter of a 0.1 mm diameter root is 0.01 mm or 2
pixels at 189 p mm-1. Because of innate variability, images need
to have a resolution that has a 4 pixel shift when a 10% change
occurs (i.e. 378 p mm-1 or better). Some pasture grasses have
fine roots in the 30 micron diameter range, requiring
resolutions of 1324 p mm-1 or a relative pixel size of 0.8
micron. We have achieved a resolution of 1600 p mm-1 by coupling
a computer controlled stepper motor X-Y-Z system to a Zeiss
dissecting microscope and a 14 Mp digital camera. The system can
be programmed to do image slicing, thus providing high
resolution images of three-dimensional objects without depth of
field artifacts.