Inspection System MASC-STEX

The automatic inspection system MASC-STEX has been developed in cooperation with Aschaffenburg University of Applied Sciences (UAS) for quality control of ceiling slabs. The system is able to reliably detect a variety of types of defects such as scratches, rough spots, and missing needles on differently textured surfaces.

MASC-STEX – Quality Control of Ceilings

Ceilings are used in buildings for fire control, heat insulation, and to upgrade the room acoustics. They are available in many different surface designs, each with other acoustical attributes. Surface defects not only reduce the overall visual impression, but also often reduce the above-mentioned functionality of the panels.

The inspection system MASC-STEX has been developed for the quality control of ceilings. The development was done in cooperation with the Aschaffenburg University of Applied Sciences (UAS). The system is able to perform a reliable detection of a variety of defects (e.g. scratches, abrasive spots or imperfect design) on many different designs. Since 2003 MASC-STEX is used successfully at a major manufacturer of ceilings in Germany.

 

Typical ceiling panel.
© Photo ITWM

Typical ceiling panel.

Since 2003 MASC-STEX has successfully been in operation with a major German manufacturer of ceiling tiles. In the picture: Ceiling panel production.
© Photo ITWM

Since 2003 MASC-STEX has successfully been in operation with a major German manufacturer of ceiling tiles. In the picture: Ceiling panel production.

Typical Surface Defects

The varying quality of raw materials or irregularities during the production process may result in a wide range of different defects visible on the panels:

 

  • nicks or edge damages
  • surface stains
  • peaks, and indentations
  • missing or wrong patterns, etc.
     

 

A further difficulty is that the above mentioned defects are mainly situated between the desired surface pattern, so that their detection is very hard even for the human eye. Besides, rough production conditions with dust and heat development represent a special challenge to the robustness of the hard- and software with respect to environmental disturbances.

System Structure MASC-STEX

  • The data is evaluated by several computers – and additionally one server as a control unit.
  • The surface of the test object is recorded at production speed by one or more high-resolution cameras with appropriate illumination.
  • Since not all defects can be detected from a single angle, the system has two lighting types – top light and oblique light.
  • Then the computer system evaluates the recorded data. The results are visualized and, if necessary, integrated into the production process.

 

Image Processing

  • A modular and freely configurable framework has been developed for the detection software allowing for efficient operations (e.g., convolutions, filters, segmentations) on the basis of the camera data.
  • The images are examined with respect to defect regions by especially optimized algorithms in a multi-stage process.
  • The surface design of the ceiling panels is dynamically faded out for the analysis.


Partner

Prof. Dr. Hans-Georg Stark, Aschaffenburg University of Applied Sciences (UAS)