Segmentation of Meristem Cells by an Automated Optimization Algorithm

Oswaldo Rojas,Walter Dewitte,Manuel G Forero,José María Menéndez ,Angharad Jones ,James A H Murray

doi:10.3390/app10238523

Abstract

Meristem cells are irregularly shaped and appear in confocal images as dark areas surrounded by bright ones. Images are characterized by regions of very low contrast and absolute loss of edges deeper into the meristem. Edges are blurred, discontinuous, sometimes indistinguishable, and the intensity level inside the cells is similar to the background of the image. Recently, a technique called Parametric Segmentation Tuning was introduced for the optimization of segmentation parameters in diatom images. This paper presents a PST-tuned automatic segmentation method of meristem cells in microscopy images based on mathematical morphology. The optimal parameters of the algorithm are found by means of an iterative process that compares the segmented images obtained by successive variations of the parameters. Then, an optimization function is used to determine which pair of successive images allows for the best segmentation. The technique was validated by comparing its results with those obtained by a level set algorithm and a balloon segmentation technique. The outcomes show that our methodology offers better results than two free available state-of-the-art alternatives, being superior in all cases studied, losing 9.09% of the cells in the worst situation, against 75.81 and 25.45 obtained in the level set and the balloon segmentation techniques, respectively. The optimization method can be employed to tune the parameters of other meristem segmentation methods.

Highlights

The Shoot Apical Meristem (SAM) is a structure located at the end of each shoot, responsible for generating almost all the surface tissue of the plant
A method for the segmentation of meristem cells was introduced in this paper, based primarily on mathematical morphology techniques
The proposed method requires the adjustment of three parameters

Summary

Introduction

The Shoot Apical Meristem (SAM) is a structure located at the end of each shoot, responsible for generating almost all the surface tissue of the plant. The identification of cells through their boundaries is a important task because it allows for the analysis of their behavior, both as individuals and in groups. Some regularity is observed in the walls in the pattern of cell shapes during cell division in the Arabidopsis Shoot Apical Meristem. The placement of new walls shows regular cell size and number of neighbors. A major problem appears when cells are clustered and have an irregular shape, in intact tissue, due to the difficulty to distinguish each cell individually and the impossibility of using shape descriptors to recognize them

Methods

Results

Conclusion