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 the scanners based on them, can be used in the imaging of shiny and mirror-like 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 determine a product’s form, surface topography, waviness, roughness and texture, thickness, flatness, 3D volume, etc. Additional features of the LCI method include its tomographic functionality, which enables the capture of 3D structures under transparent material layers, as well as its capability to simultaneously acquire 2D gray-scale (intensity) images from single or multiple surfaces with a large depth of focus that covers the sensor’s entire z range, up to 5.5 mm.