Jacopo Primicerio

Intercomparison of UAV, aircraft and satellite remote sensing platforms for precision viticulture

Precision Viticulture is experiencing substantial growth thanks to the availability of improved and cost-effective instruments and methodologies for data acquisition and analysis, such as Unmanned Aerial Vehicles (UAV), that demonstrated to compete with traditional acquisition platforms, such as satellite and aircraft, due to low operational costs, high operational flexibility and high spatial resolution of imagery. In order to optimize the use of these technologies for precision viticulture, their technical, scientific and economic performances need to be assessed. The aim of this work is to compare NDVI surveys performed with UAV, aircraft and satellite, to assess the capability of each platform to represent the intra-vineyard vegetation spatial variability. NDVI images of two Italian vineyards were acquired simultaneously from different multi-spectral sensors onboard the three platforms, and a spatial statistical framework was used to assess their degree of similarity. Moreover, the pros and cons of each technique were also assessed performing a cost analysis as a function of the scale of application. Results indicate that the different platforms provide comparable results in vineyards characterized by coarse vegetation gradients and large vegetation clusters. On the contrary, in more heterogeneous vineyards, low-resolution images fail in representing part of the intra-vineyard variability. The cost analysis showed that the adoption of UAV platform is advantageous for small areas and that a break-even point exists above five hectares; above such threshold, airborne and then satellite have lower imagery cost.

An Open-Source and Low-Cost Monitoring System for Precision Enology

Winemaking is a dynamic process, where microbiological and chemical effects may strongly differentiate products from the same vineyard and even between wine vats. This high variability means an increase in work in terms of control and process management. The winemaking process therefore requires a site-specific approach in order to optimize cellar practices and quality management, suggesting a new concept of winemaking, identified as Precision Enology. The Institute of Biometeorology of the Italian National Research Council has developed a wireless monitoring system, consisting of a series of nodes integrated in barrel bungs with sensors for the measurement of wine physical and chemical parameters in the barrel. This paper describes an open-source evolution of the preliminary prototype, using Arduino-based technology. Results have shown good performance in terms of data transmission and accuracy, minimal size and power consumption. The system has been designed to create a low-cost product, which allows a remote and real-time control of wine evolution in each barrel, minimizing costs and time for sampling and laboratory analysis. The possibility of integrating any kind of sensors makes the system a flexible tool that can satisfy various monitoring needs.

CrossVit: enhancing canopy monitoring management practices in viticulture.

A new wireless sensor network (WSN), called CrossVit, and based on MEMSIC products, has been tested for two growing seasons in two vineyards in Italy. The aims are to evaluate the monitoring performances of the new WSN directly in the vineyard and collect air temperature, air humidity and solar radiation data to support vineyard management practices. The WSN consists of various levels: the Master/Gateway level coordinates the WSN and performs data aggregation; the Farm/Server level takes care of storing data on a server, data processing and graphic rendering; Nodes level is based on a network of peripheral nodes consisting of a MDA300 sensor board and Iris module and equipped with thermistors for air temperature, photodiodes for global and diffuse solar radiation, and an HTM2500LF sensor for relative humidity. The communication levels are: WSN links between gateways and sensor nodes by ZigBee, and long-range GSM/GPRS links between gateways and the server farm level. The system was able to monitor the agrometeorological parameters in the vineyard: solar radiation, air temperature and air humidity, detecting the differences between the canopy treatments applied. The performance of CrossVit, in terms of monitoring and reliability of the system, have been evaluated considering: its handiness, cost-effective, non-invasive dimensions and low power consumption.

Mapping of vine vigor by UAV and anthocyanin content by a non-destructive fluorescence technique

Multispectral remote sensing using Unmanned Aerial Vehicles (UAV) is a promising new technique for precision viticulture because of its flexibility of use and limited cost. On the other hand, non-destructive methods to control vine vegetation status and ripening level of bunches are fundamental to produce high quality grape and top quality wines. Here, new techniques to evaluate the spatial distribution of vine vigor and phenolic maturity have been applied to the Nerello Mascalese Sicilian cultivar in the Etna region. Mapping of the normalized difference vegetation index (NDVI) was obtained by using a high-resolution multispectral camera mounted on an UAV. The spatial variability of grape anthocyanin content was detected in situ by using a fluorescence-based sensor. The two techniques appeared suitable to compare vine related information on a relatively large scale.

Individual plant definition and missing plant characterization in vineyards from high-resolution UAV imagery

ABSTRACT In the last few years, high-resolution imaging of vineyards, obtained by unmanned aerial vehicle recognitions, has provided new opportunities to obtain valuable information for precision farming applications. While available semi-automatic image processing algorithms are now able to detect parcels and extract vine rows from aerial images, the identification of single plant inside the rows is a problem still unaddressed. This study presents a new methodology for the segmentation of vine rows in virtual shapes, each representing a real plant. From the virtual shapes, an extensive set of features is discussed, extracted and coupled to a statistical classifier, to evaluate its performance in missing plant detection within a vineyard parcel. Passing from continuous images to a discrete set of individual plants results in a crucial simplification of the statistical investigation of the problem.

Influence of Canopy Management Practices on Vineyard Microclimate: Definition of New Microclimatic Indices

Meteorological parameters have a crucial influence on grapevine (Vitis vinifera L.) production quantity and quality. Most of the commonly used bioclimatic indices are not appropriate to represent intravineyard micrometeorological variability, in particular the subdaily dynamics that are important in grape maturation processes. The aim of this research was to compile a new set of micrometeorological indices and evaluate their capacity to discriminate the differences in the microclimatic daily cycle induced by different canopy management techniques, based on a statistical data set of three years (2008, 2009, 2010) of hourly data of cluster internal temperature, canopy air temperature, and solar radiation intercepted by the cluster. Data was collected in four vineyards planted with Sangiovese and Cabernet Sauvignon, located in three climatic zones of Tuscany (Italy). Starting from this data set, some new micrometeorological indices were defined using two different criteria for subdaily time segmentation: static, based on fixed hourly intervals, and dynamic, based on solar height daytime segmentation. Results showed that indices based on subdaily data better provide a better representation of vineyard microclimate than daily indices and are able to highlight microclimatic differences induced by canopy management practices. The indices more sensitive to treatments are those related to the solar radiation intercepted by the cluster parameter and relative to the Broad Daylight Index, which represent the average of micrometeorological parameters in the middle hours of the day. The proposed indices enhance the characterization of micrometeorological conditions induced by different canopy management practices and, therefore, the assessment of the within-vineyard spatial variability of environmental parameters.