Background suppression in black and white scanning

Citation

(1998), "Background suppression in black and white scanning", Sensor Review, Vol. 18 No. 3. https://doi.org/10.1108/sr.1998.08718caf.004

Background suppression in black and white scanning

Background suppression in black and white scanning

Keywords Scanners, Sensors, Visolux

Conventional scanner-style sensors will detect white objects at a greater distance than black objects. For many applications this is not an issue, but consider a row of black packages moving along a conveyor. Counting these packages is no problem for a standard reflection scanner until an unexpected light colour appears behind the boxes. The scanner counts a reflection from the light background and the tally is now inaccurate.

This is just the type of application which may benefit from the introduction of the new 23 Series background suppression scanners from Visolux. Regardless of colour and texture, these devices claim to provide highly accurate detection of the objects which pass into their view. Suppression of objects outside the scanning field is achieved via an angled arrangement between the transmitter and two receiving elements.

As the background suppression and scanning range can be adjusted up to 2,000mm, each sensor is extremely adaptable to any type of machine or monitoring application. All inputs and outputs are reverse polarity protected and short-circuit proof.

Conventional scanners can also suffer from crosstalk when mounted side by side. Reflected light from the detected object can easily return to any of the scanners, not necessarily the one that transmitted the light. To avoid this problem with neighbouring sensors, the 23 Series can be specified with a new type of electronic function. Option 104 guarantees reliable operation even with devices positioned directly opposite each other.

Although the series operates with infrared, modulated light as standard, a further option with the 23 Series is the availability of visible red light. This allows the easy setting of the scanner light spot at the correct position on the object.

Typical applications for 23 Series will be on packaging machines to control material flow, in materials handling to control stack height, shelf filling, transported goods on pallets; in the wood processing industry to detect different colours of wood reliably and on machine tools to recognise electromechanical and electronic components parts.

For further information contact Visolux Limited, 28 Clifton Road, Cambridge CB1 4ZG, UK. Tel: +44 (0) 1223 242020; Fax: +44 (0) 1223 411063.