Short Communication

Plant and Soil

, Volume 158, Issue 1, pp 145-149

First online:

Automated measurement of root length with a three-dimensional high-resolution scanner and image analysis

  • A. L. SmitAffiliated withCentre for Agrobiological Research (CABO-DLO)
  • , J. F. C. M. SprangersAffiliated withDepartment of Vegetation Science, Plant Ecology and Weed Science, Agricultural University Wageningen
  • , P. W. SablikAffiliated withTechnical and Physical Engineering Research Service (TFDL-DLO)
  • , J. GroenwoldAffiliated withCentre for Agrobiological Research (CABO-DLO)

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For measuring the length of root samples, the use of a three-dimensional (3D) scanner is proposed to address the problem of a too low resolution. The scanner's high resolution (up to 354 pixels per cm) enables in the resulting grey-value image very thin roots (diameter 100 μm) to be segmented from the background by a simple thresholding operation. After skeletonizing, total length of the roots is calculated by multiplying the number of skeleton pixels by a correction factor. A comparison with the modified Newman Line-Intersect Method showed a correlation 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.

Key words

image analysis Line-Intersect Method root length three-dimensional scanner