US Patent 7307721 Particle imaging system with a varying flow rate

A particle imaging system and a method provided for analyzing particles in a fluid; the system comprising a means for capturing image data of the fluid within a sample cell, and a means for flow control, a valve and a pump, wherein the fluid within the sample cell is periodically stopped, or slowed down, for image capturing and moved rapidly between image capturing events. Advantageously, the present invention allows to increase exposure times, which is particularly significant for fluorescent imaging at low illumination levels.