A scanning system includes a hand-held scanning device that generates two-dimensional images of a pattern reflected off an object. The system also includes a memory and processing unit. The memory stores a calibration table for the scanner and received scanned bitmap images. The processing unit generates three-dimensional information as to a scanned object. The scanning can be performed without knowledge or even precise control of the position of the object relative to the scanner. Random movement of the object during scanning is also possible. Three-dimensional information of the object is obtained from the captured images using a calibration table for the scanner. A method of calibration of the scanner is also described. The illustrated embodiment is in-vivo scanning of human teeth for purposes of orthodontic treatment planning and diagnosis.