Accurate high-speed thermal 3D shape measurement of transparent objects

In recent years, we have developed a method to measure the 3D shape of transparent, glossy, or black objects without any surface preparation. For this purpose, we optically generate structured heat patterns on the surface and use a stereo mid-wave infrared camera setup to record re-emitted thermal patterns. We have demonstrated measurements in the second range, which is still too long for many applications, e.g., 100 % quality assurance or measurements in production lines. In this contribution, we present our high-speed thermal 3D sensor, enabling the reduction of the measurement time by one order of magnitude to the range of 0.1 s. We compare the resulting accuracy with that of previous thermal 3D sensors, present measurement examples of static objects with high thermal conductivity, and demonstrate a first dynamic measurement of a transparent object.