Step-Control of a Productive Process
W Sommer · Journal of Scientific Instruments · 1946
A new combination of measuring instruments with different sets of filters is described which, when acting together with a light source and photoelectric device, provide a convenient and reliable means of controlling by degrees, or in predeterminable steps, a production process, or of inspecting to close tolerances a line of mass-produced objects. A new mathematical thesis supplies the prerequisite to an easy calculation of the densities of the filters.