| 摘要 |
PURPOSE:To improve the precision by constituting a device with a focusing optical system which projects a red heat object, an optical element for obtaining image surfaces of two systems, a visible band filter, a shorter wavelength filter, image pickup elements of two systems, and a signal processing part which binarizes photoelectric signals of them. CONSTITUTION:The device is provided with an illuminating device 2 which illuminates a red heat slab 1 and has spectral radiation in the visible range, a focusing optical system 4 which projects the slab 1, and an optical element which obtains image surfaces of two systems from this optical system 4. On the optical path branched into two, a filter 6 through which visible range radiation passes, a shorter wavelength filter 8, image pickup elements 7 and 9, and a signal processing part 10 are constituted. The spontaneous light of the red heat object 1 is detected in a shorter wavelength range of visible radiation, and the shadow light of flaws is grasped in a longer wavelength rage, and two photoelectric signals are inputted from a gain adjusting circuit to a dividing circuit, and the output is binarized. Thus, accurate and flexible flaw discrimination is possible. |
