Colour recognition with VisionTools V60

The correct pin assignment of multi-wire cables is checked by means of the cable colour. The position and colour are determined for each individual wire. The target colours of each cable are taught-in individually, using a type of construction and clicking on each individual cable in the camera image with the mouse. It is not necessary to specify colour values from RAL tables.


The CIE LAB colour space describes all perceivable colours in a three-dimensional colour space in which the brightness value L is perpendicular to the colour plane (a, b) (see

Colour images can be analysed in the V60 image analysis software using the CIE-LAB object. The object determines the LAB values of an arbitrarily parameterisable area. The LAB result value is a point in the three-dimensional colour space. Each colour has a unique coordinate. For illustration purposes this coordinate can also be displayed as a 3D coordinate.

In the figure, 7 taught-in cable colours (red, blue, violet, brown, green, pink, yellow) are shown as straight lines in the colour space. There are deviations in the LAB values due to production-dependent colour variations in the cable insulation or optical influences. The determined colour value is therefore usually slightly off the taught-in colour. If the distance of a LAB value to all taught-in color lines is calculated, the LAB value can be assigned to the colour line with the shortest distance.

The camera system manages any number of variants. The correct sequence is checked by means of a type specification and the corresponding taught sequence.

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