title: Sensor Fusion of a Mobile Device to Control and Acquire Videos or Images of Coffee Branches and for Georeferencing Trees.
abstract: Smartphones show potential for controlling and monitoring variables in agriculture. Their processing capacity, instrumentation, connectivity, low cost, and accessibility allow farmers (among other users in rural areas) to operate them easily with applications adjusted to their specific needs. In this investigation, the integration of inertial sensors, a GPS, and a camera are presented for the monitoring of a coffee crop. An Android-based application was developed with two operating modes: (i) Navigation: for georeferencing trees, which can be as close as 0.5 m from each other; and (ii) Acquisition: control of video acquisition, based on the movement of the mobile device over a branch, and measurement of image quality, using clarity indexes to select the most appropriate frames for application in future processes. The integration of inertial sensors in navigation mode, shows a mean relative error of ±0.15 m, and total error ±5.15 m. In acquisition mode, the system correctly identifies the beginning and end of mobile phone movement in 99% of cases, and image quality is determined by means of a sharpness factor which measures blurriness. With the developed system, it will be possible to obtain georeferenced information about coffee trees, such as their production, nutritional state, and presence of plagues or diseases.
authors.affiliation: Centro Nacional de Investigaciones de Café, Manizales 170009, Colombia. paula.ramos@cafedecolombia.com.|Universidad Nacional de Colombia, Bogotá 11001, Colombia. paula.ramos@cafedecolombia.com.
authors.forename: Paula Jimena Ramos
authors.initials: PJ
authors.lastname: Giraldo
authors.affiliation: Centro Nacional de Investigaciones de Café, Manizales 170009, Colombia. alvaro.guerrero@cafedecolombia.com.
authors.forename: Álvaro Guerrero
authors.initials: ÁG
authors.lastname: Aguirre
authors.affiliation: Universidad Nacional de Colombia, Bogotá 11001, Colombia. carmmunozper@unal.edu.co.
authors.forename: Carlos Mario
authors.initials: CM
authors.lastname: Muñoz
authors.affiliation: Universidad Nacional de Colombia, Bogotá 11001, Colombia. faprietoo@unal.edu.co.
authors.forename: Flavio Augusto
authors.initials: FA
authors.lastname: Prieto
authors.affiliation: Centro Nacional de Investigaciones de Café, Manizales 170009, Colombia. carlos.oliveros@cafedecolombia.com.
authors.forename: Carlos Eugenio
authors.initials: CE
authors.lastname: Oliveros
keywords: coffee plantation; field conditions; image quality; machine vision; precision agriculture; sensor fusion; smartphone