Wheat ear counting in-field conditions: High throughput and low-cost approach using RGB images.
Jose A. Fernandez‑Gallego, Shawn C. Kefauver1* , Nieves Aparicio Gutiérrez, María Teresa Nieto‑Taladriz and José Luis Araus.
Background: The number of ears per unit ground area (ear density) is one of the main agronomic yield components in determining grain yield in wheat. A fast evaluation of this attribute may contribute to monitoring the efficiency of crop management practices, to an early prediction of grain yield or as a phenotyping trait in breeding programs. Currently, the number of ears is counted manually, which is time-consuming. Moreover, there is no single standardized protocol for counting the ears. An automatic ear‑counting algorithm is proposed to estimate ear density under field conditions based on zenithal color digital images taken from above the crop in natural light conditions. Field trials were carried out at two sites in Spain during the 2014/2015 crop season on a set of 24 varieties of durum wheat with two growing conditions per site. The algorithm for counting uses three steps: (1) a Laplacian frequency filter chosen to remove low and high-frequency elements appearing in an image, (2) a Median filter to reduce high noise still present around the ears and (3) segmentation using Find Maxima to segment local peaks and determine the ear count within the image.