Patent ID: 7551279

Claim:
A system for monitoring normal levels of bacteria in liquid, the system comprising: an optical axis; a target zone, the optical axis intersecting the target zone; at least one light source configured to generate a light beam and direct the light beam through the target zone; an optic lens system configured to collect light scattered by a particle associated with the bacteria in the liquid medium in the target zone and direct the scattered light to at least one detector, the detector configured to detect the light and generate a digital signal; and a computer system coupled with the detector, the computer system configured to execute a set of programmed instructions to identify and classify the particle, compare counts per unit time to a threshold, and generate an alarm, the instructions causing the computer system to: extract events from the digital signal; calculate the similarity between the extracted event and a known event; classify the event based on the similarity; calculate a new count rate for the classification type; calculate a trend in the count rate; and generate an alarm if the trend is undesirable, wherein the similarity is determined by a calculation of the ratios of outer pixels to inner pixels and comparing between the extracted event and a known event.