At the beginning of the signal chain, the appropriate lighting has a fundamental task of providing images that can be evaluated through contrast and brightness. Among other things, the choice of lighting colour also has an effect on image acquisition. Blue, for example, is not only a beautiful colour, but also an extremely useful tool in industrial image processing. With the blue vicolux® BLUE Vision lighting, the evaluation becomes even more intensive and precise. In addition, special lenses, tuned for blue light, are another factor for optimal evaluations.
Blue light has a shorter wavelength than other colours, which means it offers higher resolution and accuracy. Blue light is also less reflected from surfaces than other colours, resulting in a higher contrast level and better detectability of features on the sample.
This allows machine vision solutions in mechanical engineering to work reliably as complex technical systems, because image acquisition with the essential process of illumination always precedes the actual image processing. Illumination brings the machine vision solution to life and vicolux® BLUE Vision lighting provide an intense precise "life".
The vicotar® BLUE vision lenses were developed especially for blue light. In combination with the matching blue vicolux® lighting, they offer maximum resolution with maximum depth of field for imaging the test object.
Illumination scenarios are possible with all types of high-power LED lighting. Area and line lights, ring lights, dome, spot and dark field lights for quality inspection in the glass industry, for the semiconductor industry and automotive as well as use in the pharmaceutical industry.
The highest precision for metrology applications is achieved in the combination of telecentric lighting with a telecentric lens. Only in this way can the beams for the outer field points also be imaged through the lens. If the aperture angle of the telecentric lens is matched to the illumination aperture of the light source, i.e. if it is not larger, only light from the test object is imaged and thus used for metrological evaluation - "false light" can thus be avoided. Light source and lens must therefore be well aligned.
Telecentric lighting provide a homogeneous light field. A caustic is created at the focal point of the illumination optics, i.e. a spot with a minimum light diameter. Ideally, the test object should be positioned there. In reality, however, due to the extremely low divergence of the beams, the object can be positioned at a free distance in front of the light source. Experience shows that this does not have a negative effect on the measurement or test result.
The telecentric lighting are particularly suitable for determining the dimensions of shiny or transparent objects such as wires, metal bolts, glass ampoules, threads and also liquid jets. Furthermore, inclusions and defects in glass or transparent materials can be made visible. These illuminations are also used in deflectometry, where the deviations from the ideal shape of reflective surfaces are to be measured. In defect detection, for example, the fact is exploited that whenever light is deflected from the ideal beam path, it is missing from the evaluation and the corresponding defect appears dark. Also in reflected light, ridges and trenches on reflective surfaces as well as paint thicknesses can be determined in this way. This is already widely used in semiconductor production.