Abstract: A method of generating a three-dimensional topological surface representation of a tyre on a vehicle, the method comprising: using a tread depth measurement device to record tread depth data for a tyre surface moving relative to the tread depth measurement device; generating a movement profile of the tyre surface; and using the movement profile of the tyre surface to map the tread depth data onto a base tyre structure, thereby generating a three-dimensional topological surface representation of the tyre.

Abstract: A hand-held device for obtaining a three-dimensional topological surface profile of a tyre, the device comprising: a base comprising an aperture; a light source arranged in use to generate an elongate pattern of light, and to project said pattern through the aperture onto a rolling surface of the tyre; a detector arranged to image a region of the rolling surface of the tyre; a plurality of pairs of guide wheels mounted on respective axles mounted on the base, wherein the guide wheels on adjacent axles are linked by gears; and a rotary encoder arranged to generate a signal corresponding to rotation of an axle.