Embedded special

harvesting B


Te harvesting process could be on the verge of a complete overhaul thanks to machine vision, Matthew Dale finds

roccoli is a difficult crop to harvest. Firstly, the window for when broccoli heads reach the correct size for picking is only three

days. If the crop is harvested too early the heads will be under developed; too late and they’ll be too large. In addition, the weight of a broccoli head that a supermarket asks for can vary from one supermarket to another, complicating the harvesting process further. Manual harvesting currently results in up to

30 per cent of crops being leſt in the field because of the speeds at which the pickers are required to work. But now a combination of machine vision, deep learning – whereby the algorithm is trained to recognise variation using lots of data – and robotics has the potential to automate and replace these manual harvesting methods. One such robotic system, being built by

integrator Capture Automation in partnership with Stemmer Imaging, is designed to harvest broccoli. ‘Ideally, vision can be used to harvest at source,’ Ky Ellen, machine vision consultant at Capture Automation, commented. ‘Te system is set up to collect a certain amount of broccoli heads of a particular size and is then sent on its way to harvest them automatically.’ Stemmer Imaging and Capture Automation

are currently involved in a long-term partnership that designs and delivers vision systems for these automated harvesting machines, which enables picking to take place outside normal working hours, according to Chris Pitt, sales manager at Stemmer Imaging. ‘Picking at night time is also more beneficial, as the product stays cooler and fresher for longer,’ he said. One of the problems with manual harvesting is that growers have no knowledge of what remains in

Vision technology can be used to discern weeds from crops, such as this pigweed growing alongside cotton plants

the field aſter some of the crop has been harvested. ‘With an imaging system, it’s not only possible to collect data on the crops being picked, but also the data of the plants leſt in the ground,’ said Ellen. ‘You can send back information on why crops have been leſt in the field, perhaps because they’re a certain size. Tis allows you to come back at a later date and harvest the rest of the field.’ Vision systems enable farmers to harvest all their

crops at the optimal time. ‘Vision technology could be used to start grazing a field as soon as growers believe their crops are close to being ready,’ Ellen explained. ‘Te system would go and only pick the crops that are ready for a particular order, while also sending data back on the crops that are leſt in the field. Tis is quite valuable, as the data can then be correlated with the weather forecast to estimate when the rest of the crops will be ready, so then the machine can be sent out again to pick everything at the right time.’ Te new automated harvesting systems are

currently still in the trial phase and are being guided using 3D vision, which offers numerous advantages over more traditional 2D imaging, according to Pitt,

32 Imaging and Machine Vision Europe • June/July 2017

such as being able to discern between weeds and crops. ‘Te main reason that 3D imaging is better for

this, is that with 2D imaging everything within the image is based on the intensity of light that’s being reflected back from the product, rather than the product’s physical shape,’ commented Ellen. ‘Terefore, with 2D imaging, the closer the product is to the camera, the brighter the image; if it’s further away, then you’ll get a darker image. Tis adds a lot of variability. ‘Part of the challenge with broccoli is separating

the leaf from the head, so if one of the leaves from one plant is covering the head of another, a 2D system will struggle to tell the two apart,’ Ellen continued. ‘With a 3D system, it can be trained to look for a domed shape and a different texture to a leaf, making them easier to separate.’ Te 3D vision system provided by Stemmer

Imaging for this application is LMI’s Gocator camera, an all-in-one calibrated solution with an IP67 rating, meaning it is both dust and waterproof, and therefore suitable for the harsh conditions experienced out in a field. A laser is used alongside


Blue River Technology

Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56