One of the challenges faced by automakers is the need to measure and inspect car bodies when they come off the production
line to make sure they've been assembled correctly and fall within specifications. Typically, using a conventional coordinate
measuring machine (CMM), this process can take from 8 to 10 hr. Time is money, especially in the auto industry.
Renault tested a prototype photogrammetric measuring system called the AdventCR, developed by the French company ActiCM. The
noncontact system uses an intelligent vision device (IVD) and software to perform geometric and surface-point measurements.
The resulting 3D measuring system can take measurements 10 × faster than current CMMs and has an accuracy of 50–300 μm, depending
on the material and measurement volume.
The system's hardware acquires the data from the IVD (a compact optical sensor that incorporates two high-resolution digital
high-definition CCD cameras and several light sources) and then software performs the image processing, photogrammetry, results
analysis, and statistics calculations. Baptiste Faivre d'Arcier, leader of Renault's Photogrammetry Applied to Car Bodies
Project, says the prototype enabled them to measure the complete car body in 2 hr. "These 2 hr. can be reduced to 30 min.
if we use four IVDs, and the cost of the system would still be equivalent to that of a current CMM. Calculations and measurements
can be deferred so that the measured part is available immediately." Renault plans to purchase an AdventCR4 in 2005. This
new system will incorporate four IVDs for much faster offline control times.
