A system and method for measuring the quality of a fluid includes an optical body forming a measurement surface configured for contacting the fluid to be measured; a light source for projecting radiant energy into the optical body and toward the measurement surface at a predetermined angle; an optical sensor module arranged for detecting an image of at least reflected radiant energy from the measurement surface, the optical sensor module includes a two-dimensional array of light sensors or pixels, each pixel having a plurality of brightness levels; and a processor for setting a brightness threshold value, comparing the threshold value to the brightness level of each pixel, and counting the number of pixels above and/or below the brightness threshold value.