A new way of precise measurement of moving object is described in this paper.
Using Laser-Fourier Transformation-CCD System and computer (for real-time processing)
We realized the dynamic measurement of tungsten filament etc.under the real-time si-
tuation, and measuring results have been achieved of linear-diameter range 1O-2OOm,
the precision 0.5% and the velocity O-l5OmImin.
Though the static precision measurement of fine wire diameter has been well re-
solved in scientific research and industrial applications, the precision measuremeit
of a moving fine wire is still a rather difficult problem. There are two kinds of
dynamic measurement of fine wire now: One is the light spot scanning method, with a
parallel beam scanning across a wire and a phototube receiving the light singnal op-
posite, the diameter of wire from 5Opm to several millimeters can be measured; the
other is to measure the shadow of fine wire with a CCD ( charge coupled device ),
the measuring range is about 0.5-30mm. These two methods can measure fine wire dy-
namically, but their accuracies are 1,ow and measuring ranges are limited. They are
not suited to measure thinner wires for too big error.
It is often necessary to measure dynamically wires thinner than 50 Itm with high
precision in industry practice, such as tungsten filament using in bulb factories,
which diameters are from 8 to 40 im. The above methods aren't suitable.
Now in some factories the weight method is used to measure fine wire diameters
but it can only obtain the mean value but not the real value of diameters, so it
affects seriously the quality of bulbs.
The new method of dynamic precision measurement we studied is to measure the
power spectrum of a fine wire with a CCD, and process data with a micro-computer at
real time. Satisfacory results have been achieved.