CH620029

A method and apparatus for automatically inspecting liquid filled containers for particulate contaminants in relative size. The method comprising the steps of illuminating the liquid with a constant intensity light source, dissecting the image of the entire illuminated liquid volume, including the meniscus, with fiber optic bundles and monitoring the fiber optic bundles with an array of constant sensitivity photo sensors. Each photo sensor continually translates the illumination value of an assigned and separate cross sectional unit area of the vial image into a voltage signal and monitors each signal for a signal change indicative of particulate movement. The interfering output signal due to the meniscus decay is corrected, and the accept/reject decision is based upon a composite signal representative of all the differentiated signals received from the array of photo sensors.