Many food manufacturers face the problem of product which is sold by weight having to fit into packages of fixed volume. This is particularly the case when making biscuits which are sold in the familiar roll-packs. Automatic measurements of product dimensions at intermediate stages of the process assist operators in keeping the product within specification. No commercially available device met the requirements for a non-contacting measuring instrument at reasonable cost but a simple adaptation of IPL's Linescan camera system provided the answer. In the device developed, a well-defined beam is projected at an angle onto the surface to be measured, and the displacement of the light spot as seen from vertically above is detected using the Linescan camera.
Ian McFarlane, Ian McFarlane,
"Development Of The "Heightscan" Thickness Gauge", Proc. SPIE 0145, Industrial Applications of Solid State Image Scanners, (1 January 1978); doi: 10.1117/12.956595; https://doi.org/10.1117/12.956595