Al. Smit et al., AUTOMATED MEASUREMENT OF ROOT LENGTH WITH A 3-DIMENSIONAL HIGH-RESOLUTION SCANNER AND IMAGE-ANALYSIS, Plant and soil, 158(1), 1994, pp. 145-149
For measuring the length of root samples, the use of a three-dimension
al (3D) scanner is proposed to address the problem of a too low resolu
tion. The scanner's high resolution (up to 354 pixels per cm) enables
in the resulting grey-value image very thin roots (diameter 100 mu m)
to be segmented from the background by a simple thresholding operation
. After skeletonizing, total length of the roots is calculated by mult
iplying the number of skeleton pixels by a correction factor. A compar
ison with the modified Newman Line-Intersect Method showed a correlati
on of r = 0.98. Besides its superior resolution, an advantage of this
type of scanner is its focusing depth, which allows root samples to be
recorded on the scanbed similarly to a camera-oriented system.