A three dimensional vision system for industrial surface topography measurement

This thesis is concerned with a research programme into a triangulation based Surface Topography Measurement (STM) system. The particular system investigated produces a series of three dimensional coordinates of points on a target surface which has been placed in front of the STM system. It is designed for use at long ranges (5m - 20m initially) and onto rough surfaces (a selection of natural materials with particle sizes up to 1cm). The system uses a laser triangulation method with a single spot projected onto the target surface and through movement of the spot over the surface a range map is built up. A simple model which describes the STM system is presented along with an equation which gives the range error, any effects on the model by the physical implementation of the STM system are then described and quantified. Performance tests carried out on the system are described and a second version of the system is then outlined which addresses deficiencies isolated in the original system. A more detailed discussion of how the range errors arise is also given. New hardware enables the received laser spot's distribution to be analysed and processed so that, in certain cases, subpixel resolution of the centre of the laser spot can be obtained. Expansion of the laser spot and varying the parameters of the optical system are examined to assess their effect over different target materials and estimates of the possible range accuracy are also given. These results presented will be used to assess the applicability of the system for use in an industrial environment. Further work connected to this research area and several industrial applications are also detailed.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

Thames Polytechnic

Year dc:date.issued

1990

Author dc:creator

• Reynolds, Matthew C.

Advisor dc:contributor.advisor

• Barnes, Roger

• TA Engineering (General). Civil engineering (General)

Language dc:language

en