Tomographic Image Reconstruction Of Plant Single Root By Electrical Impedance Tomography

Root architecture plays an important role in plant nutrient and moisture absorption, so the study on plant root architecture and growth pattern is crucial to the improvement of ecological environment and plant productivity. It is necessary to obtain root architecture of plant cheaply, fastly and easily. Electrical impedance tomography(EIT) was used to produce images according to electrical parameters distribution within the region studied. EIT has several advantages over other tomography techniques such as X-ray computed tomography(X-CT), Magnetic resonance imaging(MRI) and Ground penetrating radar(GPR) due to its portability, safety and low cost. In this paper, EIT technology was used in situ detection of the soil plant roots, and carried on a 3D EIT simulation based on the MATLAB platform, in order to provide reference for the study of plant root morphology in situ detection based on EIT imaging. Main contents were as follows:(1) This paper mainly studies the tomographic image reconstruction of soil and root simulation system which contains soil and single tree root based on EIT, and observe the influence on the reconstructed image when the reconstruction algorithm, root size, the soil water content and bulk change. The results show that it can achieve better reconstructed image when the root diameter is 18 mm, but the small root can’t be detected; the greater soil bulk, the better reconstructed image can get; the Newton’s One—Step Error Reconstructor Method has the better reconstruction results than the Primal Dual-Interior Point Method based on Total Variation regularization; Water content has a great influence on the reconstruction quality, the higher water content, the better quality of the reconstruction.(2) EIT effectively linked the image distortion and visual perception together, proposed multi-parameter image reconstruction quality evaluation method based on image processing, that was by solving the target location, size and shape information in reconstructed image, and then compared with the actual. The deviation between them was used as the evaluation indicators, then use these indicators to establish a comprehensive quantitative evaluation of image reconstruction quality deviation. This article provides a reference for the quantitative evaluation of EIT reconstructed image quality.(3) Three-dimensional simulation of EIT was done with a cylinder subdomain. Research on the influence of hardware system parameters(electrode shape, size, layout, etc.) on three-dimensional imaging of EIT. The results show, under the same conditions, the circular electrode can get better image than square electrode; higher quality reconstructed image can be obtained when the electrode layer space is 30mm; highest quality reconstructed image can be get when the electrode diameter is 6 mm. The article is to lay the foundation for establishing a three-dimensional EIT hardware and the future of experiments of three-dimensional image reconstruction for plant roots.