Comparison of open-source image-based reconstruction pipelines for 3D
maize root phenotyping
Abstract
Understanding root traits is essential to improve water uptake, increase
nitrogen capture and raise carbon sequestration from the atmosphere.
However, high-throughput phenotyping to quantify root traits for deeper
field-grown roots remain a challenge. Recently developed open-source
methods use image-based 3D reconstruction algorithms to build 3D models
of plant roots from multiple 2D images and can extract root traits and
phenotypes. Most of these methods rely on automated image orientation
(Structure from Motion) and dense image matching (Multiple View Stereo)
algorithms to produce a 3D point cloud or mesh model from 2D images.
Until now it is not known how the performance of these methods compares
to each other when applied to field-grown roots. We therefore,
investigate commonly used open-source methods on a test panel of twelve
contrasting maize genotypes grown in real field conditions in this
comparison study. These methods include COLMAP [1], VisualSFM
[2], OpenMVG [3], Meshroom [4], Multi-View Environment
[5] and Regard3D [6]. We compare the 3D point cloud model
density, number of points, and computation time. In addition, we compare
computed traits to a manually measured ground-truth for each generated
3D model to gain insight into the dependency of trait measurements on
method accuracy. The computed traits include distance between whorls and
the number, angles, and diameters of nodal roots. This comparison study
will provide first insight into the trade-off between model accuracy and
trait accuracy for future high-throughput phenotyping pipelines.