抄録
A non-contact method of speed measurement has been recently developed by the British Iron and Steel Research Association. The principle of the method is to observe the natural irregularities of a moving material, whose speed is to be measured, at two points fixed along the direction of movement and to take the correlation of the observed irregularities as means of measuring the time taken by a point on the material for travelling through the interval between the two points.
The advantages of the method are as follows: 1) The method is of non-contact type. 2) The material need not have any marking so that it is not required to have specific electric or magnetic properties. The method is applied to the measurement of a paper tape speed by simply calculating the polarity correlation. The light transmitted through the paper tape is modulated by the irregularity in thickne, itid each transmitted light is detected by a phototransistor. Thus obtained signals are quantized into binary ones, corresponding to the signs relative to mean value. Multiplication is made by a transistor logic circuit.
This method of speed measurement may have a wide range of application. High accuracy can be expected, particularly in case of relative measurement.
