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Circular Texture Deviation Sensor

IP.com Disclosure Number: IPCOM000113102D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 80K

Publishing Venue

IBM

Related People

Korth, HE: AUTHOR

Abstract

Described is an optical sensor system, that allows to detect local deviations within circularly textured patterns. The glare from the surface reflection at the regular circular texture is suppressed for 'radial' observation by a 'non-radial' illumination. This enhances the visibility of structures with a direction not perpendicular to the radius. It allows the analysis of such structures with the available image processing techniques.

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Circular Texture Deviation Sensor

      Described is an optical sensor system, that allows to detect
local deviations within circularly textured patterns.  The glare from
the surface reflection at the regular circular texture is suppressed
for 'radial' observation by a 'non-radial' illumination.  This
enhances the visibility of structures with a direction not
perpendicular to the radius.  It allows the analysis of such
structures with the available image processing techniques.

      For a fast automatic or visual image analysis the structures of
interest must be separated from possibly dominant regular patterns.
Objects with unidirectional textures allow to use a structured
illumination to enhance the contrast of otherwise hardly visible
details.

      For circular structures, as they appear when threads of fibers
are spooled or when rotating tools texturize a surface the situation
is such, that the regular structure has a known but  location
dependent direction.  Therefore, the structure of the illumination
needs to have a corresponding location dependency.

      In order to detect small deviations of the fiber direction at
the side of a spool of, say, synthetic fibre, these have to be
enhanced in their visibility.  The light that impinges upon the fibre
will be reflected partially at the surface of the fibre.  Another
part shines through the fibre and may be reflected at the surface of
a fibre below.  Irregular reflection produces straylight that will be
radiated into a large spatial angle.  Scattering within the fibre
produces light pipe effects.

      If the fibre is arranged along a circular arc, then the light
that impinges perpendicularly to the fibre will be deflected in
radial direction.

      When the observation is made from a radial direction, e.g. with
a CCD-camera located close to the axis of the spool, then no light
reflected at regularly arranged fibres hits the camera, when radial
i...