terclim by ICS banner
IVES 9 IVES Conference Series 9 Implementation of hyperspectral image analysis for evaluating table grape quality on bunch and berry level

Implementation of hyperspectral image analysis for evaluating table grape quality on bunch and berry level

Abstract

Typically, subjective, and visual methods are used by grape growers to assess harvest maturity. These methods may not accurately represent the maturity of an entire vineyard – especially if extensive and representative sampling was not used. New technologies have been investigated for improved harvest management decisions. Spectroscopy methods utilizing the near-infrared region of the light spectrum is one such technology investigated as an alternative to classic methods and particularly the application of hyperspectral imaging (HSI) has recently gained attention in research. HIS is a spectroscopic technique that obtains hundreds of images at different wavelengths collecting spectral data for each pixel in the sample i.e., providing both spectral and spatial data.
In this study HSI in the visible-near infrared (VNIR) and short-wave infrared (SWIR) regions was tested for determining total soluble solids (TSS), pH and total acidity (TA) of table grapes under laboratory conditions. Imaging of whole bunches as well as individual berries selected from top, middle and bottom positions of bunches was done. The bunches and berries were collected over multiple samples sessions throughout the 2022-23 and 2023-24 seasons allowing for fruit of various maturity levels (unripe though to harvest maturity) to be included. Spectral data was extracted from the images using MATLAB codes developed for this purpose using different analysis approaches. The resulting data is spatial and numerical yielding mean reflectance per pixel across points for entire bunches, and entire berries. Models for determining grape chemical composition were developed using ground-truthing data collected from the sampled fruit. Initial results indicate that this method could be suitable for determining grape ripeness on a bunch or berry level.

Download the abstract

DOI:

Publication date: June 14, 2024

Issue: Open GPB 2024

Type: Poster

Authors

Talitha Venter1*, Rodrigo Oliva-Mancilla1,2, Fikile Wolela1, Eunice Avenant1,3, Carlos Poblete-Echeverría1 *

1 South African Grape and Wine Research Institute, Stellenbosch University, Private Bag X1, Stellenbosch, South Africa, 7602
2 Global technical consultancies, 05 Barn Road, Bergvliet, Cape Town, South Africa, 7945
3 South African Table Grape Industry, PO Box 2932, Paarl, South Africa, 7620

Contact the author*

Keywords

table grapes, hyperspectral imaging, ripeness, quality, spectroscopy

Tags

IVES Conference Series | Open GPB | Open GPB 2024

Citation

Related articles…

The effect of Nitrogen and Sulphur foliar applications in hot climates

ine nitrogen deficiency can negatively influence the aroma profile and ageing potential of white wines. Canopy management can alter vine microclimate, affect the nitrogen availability and influence the response of leaf senescence. Increasing the nitrogen availability to vines can increase the Yeast Assimilable Nitrogen (YAN) levels in harvested fruit and wine. Studies show that foliar nitrogen and sulphur applications at véraison, on low YAN Sauvignon blanc grapes have an effect on the level of amino acids (Jreij et al. 2009) and on S-containing compounds such as glutathione and thiols (Lacroux et al. 2008), which in turn can influence the formation of major volatiles and the aroma profile of the wine.

Read More

The influence of vine row position in terraced Merlot vineyards on water deficit and polyphenols – case study in the Vipava Valley, Slovenia

A study was conducted in the Vipava Valley (Slovenia) to understand the effects of positioning rows of Merlot (Vitis vinifera L.) vines on terraces on plant available water, yield, and grape composition

Read More

Effetti del cambiamento climatico europeo sulle epoche di vendemmia in Abruzzo

I dati termo-pluviometrici del periodo 1971-2009 registrati da alcune stazioni della regione Abruzzo sono stati analizzati adottando alcuni semplici indici climatici e bioclimatici. E’ stato valutato il verificarsi di cambiamenti climatici così come le loro ripercussioni sulle date di inizio vendemmia.

Read More

Conservation of intravarietal diversity in France: exhaustive overview and perspectives

Since the renewal of the French vineyard after the Phylloxera crisis, the panorama of cultivated varieties has dramatically changed. This current genetic erosion is due to the increasing interest

Read More

Recent advances in measuring, estimating, and forecasting grapevine yield and quality

Grapevine yield and fruit quality are two major drivers of input allocation and, ultimately, revenue for grape producers. Because yield and fruit quality vary substantially from year-to-year and within a single block, opportunities exist for optimization via precision management activities that could lead to more profitable and sustainable grape production. Here, we review recent advances in the techniques and technology used to measure, estimate, and forecast grapevine yield and fruit quality. First, we discuss direct “measurement” of yield and quality (i.e. ground-truth data generation), with an emphasis on potential for scalability and automation. Second, we discuss technology and techniques that do not directly measure yield and quality, but use correlated measurements for their estimation.

Read More