Abstract: An apparatus is described for detecting particulates on or defects in a transparent media. The apparatus includes a light source, and an array of light-sensitive elements, each of which produce an electrical signal indicating a characteristic value based on light incident on the element. The first array is disposed a predetermined distance from the at least one light source so that the transparent media may be placed between the light source and the array. An addressing circuit reads the characteristic values produced by each element, and an analog-to-digital converter circuit digitizes the characteristic values, producing digitized values. A processor processes the digitized values to determine whether a particle or defect is present at least based on a position of the shadow cast by the particle or defect on the array. A method for detecting a particulate or defect on or in a transparent media is also described.