Development of a new high-speed measuring system to analyze the dental cast form.

A new non-contact measurement system employing of a line laser and CCD camera was developed to rapidly measure maloccluded dental casts with large depth and high accuracy. In this system, the measuring interval along the line laser and the model scanning direction perpendicular to the line laser were both 0.2 mm. By averaging the raw data through repetitious input and smoothing by local filtering, the noise was effectively decreased. Sub-pixel processing, which calculates the pixel position with the largest brightness within one pixel, improved the accuracy in the measurement to 22 microns compared with 65 microns before sub-pixel processing. Dental casts with malocclusion were measured with this system. The time and the depth for the measurement were about 10 minutes and 60 mm, respectively. This was a vast improvement compared with our previous system employing a point laser. In the CG of the measured dental casts, smooth and detailed surface morphology were sufficiently reproduced, and recognition of the characteristic points in the cast could be accomplished with the accuracy of 30 microns. This measurement system will be helpful to analyze the dental cast form with malocclusion in progress.