High-speed color imaging and ratio temperature radiometer by multispectral optics

In order to analyze mechanism of melting and deformation of metal while it is being rapidly heating, or a combusion process, it is important not only to measure the time displacement of a sample and its acceleration, but to measure the change in the temperature distribution of the sample over time. For this purpose, we have developed a new Multi-Spectral Optics. By mounting combining a high-speed camera with our Multi-Spectral Optics system, we have successfully acquired a temperature distribution map and its color image simultaneously. In our system, a color image is composed with three spectrum images from wavelengths, 450 nm, 550 nm and 750 nm. A temperature distribution map can be created from two images in the near infra-red wavelengths, 750 nm and 850 nm, which were obtained by applying the ratio temperature pyrometry method. However, in order to observe and analyze rapid deformation of a sample, it is important to capture vivid images in color. This task requires additional external light. Since a high intensity of emitted light will cause an error in temperature, it is very difficult correctly to measure temperature and deformation of the sample at the same time. Temperature measured with near infra-red lights is not be influenced by the external surrounding light. In particular, for taking photos of welding phenomena, it is possible to capture clear images with excessive lighting without affecting temperature measurement. Moreover, in combustion phenomenon, it is possible to avoid the influence of chemiluminescence caused by radicals such as C2 in flame.