Method and apparatus for assessing discrete objects.

摘要

An object (22) is assessed in relation to a factor related to its silhouette (for example area) by being positioned adjacent a sheet (10) of a material having pyroelectric properties, such as polyvinylidene fluoride. The object (22) and sheet (10) are exposed to a source of radiant heat, such as a flash tube (16) to induce an electric chsrge in the sheet (10) of an amplitude related to the area of the sheet (10) obscured by the object (22). Other embodiments are described suitable for the assessment of other factors, such as shape and orientation.