Patent ID: 7543750

Claim:
A device for scanning a surface, comprising: a housing having a scanning area defined therein; a self-mixing laser sensor positioned in the housing to direct a laser beam through the scanning area, wherein, when the scanning area is moved across a scanned surface: the laser beam is directed through the scanning area to the scanned surface and light backscattered from the scanned surface is received by the laser sensor, and the laser sensor outputs a signal having a frequency indicative of a velocity of the scanned surface relative to the scanning area and having an amplitude indicative of a color of a portion of the scanned surface struck by the laser beam; and at least one processor configured to: determine a velocity, relative to the scanned surface, based on the sensor output signal frequency, determine dimensions of a first type of region on the scanned surface and of a second type of region on the scanned surface, wherein the first type of region is more darkly colored than the second type of region, receive multiple sets of data, each of the data sets including a velocity, a time and an amplitude, calculate multiple distances using the velocities and times in the data sets, determine, during a single scan, dimensions of multiple first type regions and of multiple second type regions on the scanned surface, and determine whether each of the calculated distances is a distance across one of the first type regions or across one of the second type regions.