Automatic reading of DOT codes

Volvo uses laser scanners from Micro-Epsilon for automatic tire inspection and for reading DOT codes. It is not possible to use conventional vision systems due to the lack of contrast of the letters on the tires. With the scanCONTROL 2750 laser scanner, a tire wall height profile can be produced in less than 5 seconds. No particular contrast ratio is necessary. The challenging black rubber surface of the tires requires the scanCONTROL to operate at high speed. The scanCONTROL 2750 is operated with a profile frequency of 2kHz, providing more than 1 million calibrated measuring points per second. This means that one height profile has a resolution of more than 640 x 9,000 calibrated measurement points.