Experimental Results
The testing procedure of the proposed flatness inspection system is divided into two phases: quantitative testing carried out in the laboratory and qualitative testing proposed to be carried out in the industrial facility.
Once the system is calibrated, quantitative testing is carried out using a mechanical device working as a strip emulator, which replicates the vertical movements of the surface of a rolled product presenting flatness defects when it moves forward along a production line. The magnitudes of the emulated flatness defects are known with some uncertainty, the greater the magnitude of the emulated flatness defect is, the greater the uncertainty. The system must detect the laser stripe projected onto the strip emulator in the same way as it was projected onto the surface of a rolled product, and compute the 3-D surface reconstruction of the emulated strip. Once the 3-D surface reconstruction of an integration interval of the strip is available, the system must compute a new flatness profile.
The quantitative testing of the proposed flatness inspection system consists of 40 experiments. Each experiment measures the flatness of an emulated strip 30 times. The surface of the strip is considered to be composed of 200 fibers. The experiments are classified into four groups, at a rate of 10 experiments per group, emulating low, medium, high, and very high flatness defects, respectively. Table 2 summarizes the results of these experiments, showing the mean error and error dispersion with 90% confidence for each flatness defect range evaluated. Taking all the experiments into account, the measurement error is within the uncertainty interval of the magnitude of the simulated flatness defects and the absolute error is always