In the late 2000s, researchers at Technical Research Center of Finland (VTT) invented a new optical method to image 3D microtopography of surfaces at sub-micron resolution. This method, called line confocal imaging (LCI), is based on capturing a continuous line of light reflections in visible spectrum from more than 2,000 lateral surface points simultaneously.
Line confocal sensors—and scanners based on them—are used in the imaging of surfaces, transparent materials, and multi-layered structures in various metrology and inspection applications on discrete parts, assemblies, webs, and other continuous products. Imaging results can be used to characterize a product’s form, surface topography, roughness, flatness, thickness and 3D volume. The LCI method also has a tomographic functionality, which enables the capture of 3D structures under transparent layers, as well as the simultaneous acquisition of 2D gray-scale (intensity) images from single or multiple surfaces with a large depth of focus covering the sensor’s entire z range, up to 5.50 mm.