By Silvia Stoll
[email protected]
MAY 8, 2008--Although an exact classification is not always possible, vision sensors chiefly differ from smart cameras in that they are specific to certain testing procedures, the picture resolution is often not so high, and optics and illumination devices are already integrated. While smart cameras in 2006 showed a 19% increase in sales compared to the previous year, according to an industry survey carried out by the VDMA (the German Engineering Federation) Machine Vision Group, vision sensors boasted an impressive increase of 157%. Thus, the VDMA has recently assigned vision sensors their own product category.
At VISION 2008 (4 to 6 November 2008; Stuttgart, Germany), the escalating growth of vision sensors will be clearly seen. Because exhibitors such as Baumer, Cognex, Siemens, and Vision & Control are experiencing the current boom, "this year, with regard to inspection sensors, we are expecting an increase on a scale of more than 100%, which could even be higher regionally," says Torsten Zöller, senior marketing manager with Cognex, Europe Central.
"We are currently experiencing a stormy growth period, which we trace back to both our new products and the potential of the vision sensors. Their technology and the general concept not only provide for the development of new applications but also new markets," says Ralf Grieser, smart vision market and product management executive at Baumer Optronic.
Image-based sensors fill a gap between the classic optoelectronic sensor and a smart camera. "They combine the features of high-performance sensors with the efficiency of simple machine-vision systems. They assume many tasks of classic sensors at a rapid pace, as well as more simple machine-vision solutions," says Zoller.
The application areas of vision sensors for specialized testing procedures are diversified. Siemens, for example, uses vision sensors with area color evaluation for the inspection of labels, tags, stickers, and sealing elements on packaging units, blister packaging, bottles, cans, and cups, as well as position, presence, and completeness monitoring of small parts during assembly and manufacturing processes. For example, plastic bottle caps must be checked as to whether the correct cap is available before labeling begins. "In many applications, area color evaluation has advantages over point evaluation," says Jens Hauffe, machine vision product manager with Siemens, "because often there are multicolored elements that can be dependably assessed by means of an area color evaluation."
"Currently, not all tasks can be resolved with vision sensors," says Jürgen Geffe, managing director of Vision & Control, "however, development in this area is unstoppable." For example, Vision & Control sees an almost inexhaustible pool of applications in the combination of robotics, automation, and machine vision. "Through the application of vision sensors," explains Geffe, "robots are becoming increasingly more independent and can autonomously solve tasks in automation processes." Another trend lies in the use of multihead vision sensors for the inspection of objects from several perspectives.
"We increasingly await a synthesis of modern machine-vision technology and simple sensor technology, combining the two advantages," says Hauffe. Yet more processing power within a smaller space will make vision sensors ever more effective in the future.
In addition to this, according to Grieser, there is emphasis on topics such as user friendliness, interchangeability, and the availability of components, the stocking of spare parts, as well as service and maintenance concepts. These points will become more important for the purchase decision in the future.
