3D VISUALIZATION OF ROOT SYSTEM IN SITU BASED ON X-RAY CT TECHNOLOGY

摘要

The root is an important plant organ for nutrient and water uptake from the surrounding soil. Because of the special growing environment and complex structure, the root system is more difficult to quantify than the shoot. Observation and measurement of root architecture in situ has been a technical bottleneck for research on plant root systems. To solve the technical problem, the three-dimensional visualization of root system in situ was implemented with using X-ray CT technology in this paper. By means of MSCT scanner, the experiments to acquire images of plant roots in situ were done at first for several varieties plant roots including soybean, banyan seedling and so on, which were growing in different mediums including red soil, fine sand and organic soil. And it was proved that the method plant root imaging in situ based on XCT technology was feasible. Based on the spatial geometrical and morphological features of root systems, a recursive segmentation algorithm with slice by slice is proposed and implemented. It was able to clean markedly up the pixels non-root regions of which the gray levels were very similar to roots' regions and the positions were very close to roots' regions. And it was very effective to improve the accuracy and stability of segmentation for the CT images of root systems in situ. For implementing the three-dimensional reconstruction of root systems in situ, an improved of MC (Marching Cubes) algorithm with the permeation of segmenting processing was proposed, and it broke through the limit of using thresholding segmentation and avoided repeating time caused with segmentation and reconstruction running separately. The three-dimensional visualization of plant roots in situ was implemented under the environment of PC with some basic functions of measurement for root architecture.