This book covers a wide range of measurement techniques broadly referred to as Optical Metrology, with emphasis on their applications to nondestructive testing. If we look separately at each of the two terms making the generic name Optical Metrology, we find a link to two of the most distinctive aspects of humans: a particularly well developed sense of vision and a desire to classify things using numbers and rules.

Of all our five senses, vision is certainly the most developed and the closest to the rational part of our brain. It can be argued that our memory is strongly dependent on images and the brain is particularly good at processing the stimuli received from these images to extract information. Measuring, sizing and counting are, on the other hand, among the fundamental building blocks of modern society. The use of abstract quantities like size, value or intensity has simplified the description of complex enquiry and is the basis of modern science and economy. Hence, it (...)