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ANALYSIS
New Pioneering Technology to Objectively Evaluate Total Perception of Structured Surfaces Christopher Groh, Jonas Harmeling and Gabriele Kigle-Böckler BYK-Gardner GmbH – Geretsried, Germany
gabi.kigleboeckler@altana.com
Our visual perception is influenced by colour, gloss and the surface structure. Our visual rating takes all three parameters into consideration and makes an overall judgement. Up to now, grain or surface structure could only be judged visually or with high sophisticated microscopes. This has changed with the new spectro2profiler, a pioneering technology combining colour, gloss, 2D reflectivity and 3D topography in a robust, portable tool with a short measuring time. Introduction - Colour analysis is not enough
structure or complex gloss behaviour of
Uniform appearance is a crucial quality
used to provide very detailed information of
criterion for many products. The choice of
the surface structure in the laboratory for
material and production process variations
research purposes, but not suitable for fast
influence the surface quality, for example
and easy analysis of production quality.
3D-surfaces. Therefore, 3D microscopes are
the cell size of powder coatings is highly conditions. Another example are injection
3D Topography analysis using photometric stereo technique
moulding applications where fluctuations
Photometric stereo is a technique for
in tool pressure and temperature will show
estimating surface normals in order to
up in gloss and contrast variations. With
calculate a 3D topography of that surface.
the change of just one material or process
The technique was originally introduced by
parameter, the visual perception of colour
Woodham in 19801. The surface normals
and appearance can be changed significantly.
are calculated by observing an object from
So far visual assessment was the only way to
different illumination directions. With each
deliver a complete judgement of a textured
direction, the object casts different shadows
dependent on paint film thickness and curing
surface including colour and gloss evaluation. The recent developments of colour and gloss meters significantly improved quality control, but do not include the effects of
Woodham, R.J. 1980. Photometric method for determining surface orientation from multiple images. Optical Engineerings 19, I, 139-144
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Detail of Color Study, Squares with Concentric Circles by Vassily Kandinsky, 1913.