Estimation of harvested fruit weight using volume measurements with distance sensors: a case study with olives in a big box.

The introduction of fruit tree harvesters on the market allows the opportunity to incorporate new yield monitors. Traditionally, yield has been measured by in-the-field fruit batch weighing systems that employ load cells, which present certain problems as well as oscillations and outliers. We propose the development and evaluation of two distance measurement systems (an experimental one using an array of sensors with low-cost, Time-of-Flight technology and another, commercial system, with a 3D camera) to estimate the volume of fruit harvested in a big box and correlate the volume with its weight. To this end, two algorithms were developed to estimate the volume of fruit filling. Several tests were conducted to determine the field of view of the sensors and the influence of illumination, reflectivity of different surfaces, and vibrations in transit on the measurements they give. Illumination was a limiting factor on the accuracy of the experimental system and required...