Online Surface Temperature Measurement of Billets in Secondary Cooling Zone End-Piece Based on Data Fusion

In order to eliminate the influences of surface stripped iron oxide scale, dust and emissivity on temperature measurement for casting billets, a novel surface temperature measurement system based on multisensory information fusion technology is described in this paper. The system consists of a visible imaging charge coupled device (CCD) camera with high resolution, a colorimetric thermometer, an optical filter and associated software processing units. It makes use of the high resolution characteristic of CCD and the distribution character of surface temperature field of casting billets to reduce the temperature fluctuation aroused by the surface stripped iron oxide scale, and the spot temperature measured by the colorimetric thermometer is fused into the temperature field measured by the CCD camera to overcome shortcomings of merely using the CCD camera in temperature measurement, such as being susceptible to dust at wide field, and not capable of obtaining true temperature because of inconclusive emissivity for different grades of steel. In order to validate the effectiveness of the method proposed in this paper, temperatures of different grades of steel are measured by this system, and temperature is also measured by this system during the changes of the casting speed and the volume of the cooling water. All these measurement results show the maximum fluctuation of the temperature measured by this system was +/- 5 K and the surface temperature of casting billets measured by this system can reflect changes of processing parameters in the continuous casting production line in real time. Thus, the temperature measured by this system can be used as a feedback control parameter to improve the control for dynamically adjusting water distribution and casting speed in practical application.