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SECTION 10 SPRAY APPLICATION This section brought to you in association with
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Seeing green on green: A new way to look at weed control By Guillaume Jourdain, Bilberry
AT A GLANCE… • Green on green camera technology is now used on farms. This will lead to important financial and farm management benefits for growers. • Growers need to not only understand the benefits – but also the limitations – of new technologies such as green on green weed detection.
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wo optical camera systems to spray weeds have been on the market for several years – WEEDit and WeedSeeker. These systems are now commonly used in Australia for green on brown applications. A number of start-up companies (such as Bilberry), large corporations and universities are now developing systems with green on green capability – that is, being able to identify a weed in a growing crop and selectively spray the weed. The technology used by the various companies in this green on green space is similar: Artificial intelligence with cameras – sometimes RGB/colour cameras and sometimes hyperspectral cameras.
shape. Through mathematical formulas, a range of colours and a range of shapes for each weed can be identified. In other words ‘conventional’ algorithms – which set out a process, or the rules to be followed by the machine – to identify the weed, can be created. Figure 1 shows a very simplified example. Conventional algorithms can identify radish in the laboratory because the weed colour sits within a specific green range. This is all very well in the laboratory under controlled conditions with constant light, no wind, all crops and weeds are from the same variety and are not stressed etc. But paddock conditions are completely different. The sun can be high or low, in your back or in your eyes, there can be clouds, there can be shadows from the tractor/sprayer cabin or from the spraying boom, crops can be damp in the morning which creates sun reflections, the soils always have different colours and so on.
Using artificial intelligence (AI) to detect weeds Finding machine-based methods to recognise weeds within crops has interested high-tech companies and researchers for a very long time. The first patents on this topic date back to the 1990s. The main approach was to differentiate weeds from crops thanks to their colour and
FIGURE 1: A simplified example using conventional algorithms to identify radish in the laboratory
Bilberry cameras on an Agrifac 48 metre selfpropelled sprayer. 138 — COTTON YEARBOOK 2019
