Optical system for inspecting porous substrates

An automated system for inspecting a porous substrate using a sample, comprising,

• a delivery device fixed along a sample axis to apply a sample to a target point on a porous substrate, wherein the sample axis is perpendicular to the porous substrate;
• an imaging device and one or more lenses, positioned so that the imaging device and the lens each has a focus axis that is parallel but offset translationally from the sample axis, and the combination of the imaging device and the lens has a viewing focal point that is substantially the same as the target point;
• a light source that is offset from the delivery device to illuminate the surface target;
• and
• a processor comprising a data acquisition and control system that coordinates timing and automation of the delivery and imaging devices, and determines one or more characteristics of the porous substrate.