Peanut Maturity Classification using Hyperspectral Imagery

TL;DR

This paper presents a hyperspectral imaging method for objectively classifying peanut seed maturity, eliminating manual removal of hulls and reducing observer variability, with high accuracy and potential for seed quality research.

Contribution

Introduces a hyperspectral imaging technique for non-destructive, accurate peanut maturity classification that overcomes limitations of manual visual assessment.

Findings

High classification accuracy across different years and cultivars

Capable of estimating continuous maturity values at pixel level

Reduces labor and subjective errors in maturity assessment

Abstract

Seed maturity in peanut (Arachis hypogaea L.) determines economic return to a producer because of its impact on seed weight (yield), and critically influences seed vigor and other quality characteristics. During seed development, the inner mesocarp layer of the pericarp (hull) transitions in color from white to black as the seed matures. The maturity assessment process involves the removal of the exocarp of the hull and visually categorizing the mesocarp color into varying color classes from immature (white, yellow, orange) to mature (brown, and black). This visual color classification is time consuming because the exocarp must be manually removed. In addition, the visual classification process involves human assessment of colors, which leads to large variability of color classification from observer to observer. A more objective, digital imaging approach to peanut maturity is needed, optimally without the requirement of removal of the hull's exocarp. This study examined the use of a hyperspectral imaging (HSI) process to determine pod maturity with intact pericarps. The HSI method leveraged spectral differences between mature and immature pods within a classification algorithm to identify the mature and immature pods. The results showed a high classification accuracy with consistency using samples from different years and cultivars. In addition, the proposed method was capable of estimating a continuous-valued, pixel-level maturity value for individual peanut pods, allowing for a valuable tool that can be utilized in seed quality research. This new method solves issues of labor intensity and subjective error that all current methods of peanut maturity determination have.