| 摘要 |
Particles are classified according to their thermal properties by means of a method in which the first step is that of deriving a first matrix composed of first emitted heat energy values for the particles (16, 18) with the particles at a uniform temperature. This is achieved using a first thermal camera (22) to derive a thermogram which is analysed by a CPU (24). Next, the CPU calculates emissivity equalisation factors which equalise the values in the first matrix when the values are adjusted by the factors. Then the particles are heated or cooled, typically by an infra-read beam (26). A second matrix composed of second emitted heat energy values is then derived, by the CPU, for the heated or cooled particles, using a second thermal camera (28). The CPU adjusts the values in the second matrix by the earlier derived emissivity equalisation factors, thereby producing adjusted heat energy values for the particles. Finally, the particles are assigned classifications according to the magnitude of their adjusted heat energy values. The invention is applicable to recovering diamonds (16) from gravel (18). <IMAGE> |
