The automatic Gauge Block Interferometer (GBI) employs the principle of multiple wavelength coincidences to precisely and accurately calibrate lengths. It measures gauge block lengths ranging from 0.1mm to 250mm by employing optical interference, which is automatically detected via interference fringe analysis software along with a CCD camera and then the data is processed and displayed.
Parallelism and flatness is measured through appropriate measurement provisions. Highly accurate and repeatable measurement is achieved by GBI on account of the highly stable intensity and wavelength of the He-Ne laser light sources. Thermometer, hygrometer and barometer connected to computer automatically compensate the refractive index of air and the thermal expansion of gauge blocks.