CANTY imaging systems have been involved in the control to improve yield of fermentation for several years. Measurement of cell size, concentration and viability in real time in batch and perfusion type fermentation is critical to the process yield. The measurement of foam allows operators independent control of anti-foam additions. The measurement of cell size, count, viability and concentration in the lab or at-line is accomplished by our imaging based system which can distinguish a cell form a gas bubbles and other trace particles.