苹果初期损伤温度变化导致光谱特征演化机理研究

Evolution Mechanism of Temperature-driven Spectral Characteristics of Initial Damage in Apples

摘要:

为提升商品果品质，及早进行机械损伤检测至关重要。针对苹果初期损伤部位光谱演化机理不明，导致损伤检测模型识别准确性和鲁棒性较低的问题，本文采集蛇果机械损伤初期（0~2h）损伤演化过程的损伤区域和未损伤区域的温差时序数据，并结合敏感波段（1255~1314nm）的光谱特征，利用Granger因果检验方法揭示和论证了温度变化导致光谱特征演化的机理：随着苹果损伤时间推移，温差先上升后下降，而后趋于平稳，且损伤越严重，温差越大；Granger因果检验结果表明，苹果损伤部位温度变化是导致其特征波段1255~1314nm的光谱特征发生变化的主要原因；损伤越严重，温差对图谱特征的影响越强；光谱特征R在损伤后苹果表面温度表征上更具有代表性和全面性。通过对蛇果损伤后光谱特征演化机理研究，为后续更可靠地进行苹果初期轻微损伤检测提供了研究思路和理论依据。

Abstract:

To enhance the quality of commercial fruits, it is imperative to detect mechanical damage at an early stage. Aiming to addresse the issue of unclear spectral evolution mechanisms in the early stages of fruit damage, leading to low accuracy and robustness of the damage detection model. The temperature difference time series data of damaged and undamaged areas in the early stages (0~2h) of mechanical damage was collected to Red delicious apples, and combined it with the spectral features of sensitive bands (1255~1314nm) by using the Granger causality test method to reveal and substantiate the mechanism of spectral feature evolution caused by temperature changes: with the progression of apple damage, the temperature difference was firstly risen, then fell, and finally stabilized. The more severe the damage was, the greater the temperature difference would be. The results of the Granger causality test indicated that the main cause of the change in the spectral features of the apple’s damage site in the 1255~1314nm characteristic band was the change in temperature at the site of damage. The milder the damage was, the weaker the influence of the temperature difference on the spectral features would be. The spectral features R were more representative and comprehensive in characterizing the surface temperature of the apple after damage. Through the study of the evolution mechanism of spectral features after the Red delicious apples was bruised, the research result can provide a theoretical basis and research approach for more reliable early detection of minor apple damage.