Research On Key Technology For 3-D Shape Measurement Of Shoe Last With Laser Triangulation

Optical 3-D profilometry has a series of merits, such as noncontact, unabroken, higher precision, higher speed and automation. Optical 3-D profilometry is used as tools widely for industry measurement, machine vision, reverse engineering, profile modeling, shoemaking engineer, biomedical industry, etc. Laser triangulation is based on traditional triangulation. It is used the most widely.In the shoemaking industry, no mater the sample last newly designed, or the last volume-produced, must be measured or tested for the characteristic dimension and the shape of the last. Last is the benchmark of shoe style. The 3-D surface data of the whole last is required in the CAD/CAM system. This paper has done some embedded research of key technology for 3-D shape measurement of shoe last with laser triangulation in to improving the measurement precision. What we have achieved are as following:1. The hardware system has been improved: Linear array CCD of higher resolving power is chosed to improve the higher precision; The structure is simplified by in-system programmable system; Speed is increased by using high speed A/D convertor and frame memorizer.2. Present a method of obtaining the distance and intensity imformation of the facular image. Self-adaptive light intensity regulatingtechnique and high precision arithmetic of the center position of the facular image is used.3. Analyze the system's precision influence factors, the speckle noise and its influence. Briefly introduce the methods of improving system's measure precision.4. There're several methods of working out the center position of the facular image, such as center of gravity method, fourier transform method, function fitting method, etc. They're analyzed and compared in the paper.