Method and apparatus for the three-dimensional registration and display of prepared teeth

In a method for noncontact topographic scanning of a three-dimensional contour on an object, including the steps of:

• directing a predetermined intensity pattern of light onto the contour so that a corresponding intensity pattern of light will be backscattered therefrom, the varying intensity pattern of said backscattered light being a measure of the three-dimensional contour on the object;
• directing said pattern of said backscattered light onto electro-optical light sensing means;
• periodically reading from said light sensor means electrical data representative of the image directed onto said sensor and displaying said electrical data on a video display;
• thereafter successively moving said intensity pattern relative to the object to at least two different positions and reading from said light sensor means for each said position of said pattern a respective set of electrical data, and storing each said set of electrical data;
• and calculating from said stored sets of electrical data a digital three-dimensional image of the contour;
• the improvement comprising the step of calculating from said stored sets of electrical data a digital two-dimensional contrast image of the contour and the step of continuously displaying on said video display said two-dimensional contrast image, said contrast image being for each point on the contour the difference between the respective backscattered light intensities detected by said light sensing means for illumination of said point with maximum and minimum light intensities of said pattern.

In an apparatus for noncontact topographic scanning of a three-dimensional contour on an object, including means for directing a predetermined intensity pattern of light onto the contour so that a corresponding intensity pattern of light will be backscattered therefrom, the varying intensity pattern of said backscattered light being a measure of the three-dimensional contour on the object;

• means for directing said pattern of said backscattered light onto electro-optical light sensing means;
• means for periodically reading from said light sensing means electrical data representative of the image directed onto said light sensing means;
• means for displaying said electrical data on a video display;
• means for thereafter successively moving said intensity pattern relative to the object to at least two different positions, for reading from said light sensor means for each said position of said pattern a respective set of electrical data, and for storing each said set of electrical data;
• and calculating means for calculating from said stored sets of electrical data a digital three-dimensional image of the contour;
• the improvement comprising wherein said calculating means includes means for calculating from said stored sets of electrical data a digital two-dimensional contrast image of the contour, and including means for thereafter continuously displaying on said video display said two-dimensional contrast image, said contrast image being for each point on the contour the difference between the respective backscattered light intensities detected by said light sensing means for illumination of said point with maximum and minimum light intensities of said pattern.

In an apparatus for noncontact topographic scanning of a three-dimensional contour on an object, including:

• light source means for generating light and means for directing light from said light source means onto the contour;
• pattern generating means disposed in the path of the light from said light source for imparting to said light a predefined pattern of intensity;
• light sensor mans at a predetermined location;
• and means for directing light backscattered from said contour onto said light sensing means;
• the improvement comprising wherein said pattern generating means includes a liquid crystal cell having therein a liquid crystal material through which light traveling from said light source means to said object passes, said liquid crystal cell having electrode means responsive to electric stimulation for generating transparent regions and opaque regions in said liquid crystal material in the form of said predefined pattern.

In an apparatus for noncontact topographic scanning of a three-dimensional contour on an object, including:

• light source means for generating light and means for directing light from said light source means onto the contour;
• pattern generating means disposed in the path of light from said light source means for imparting to said light a predefined intensity pattern;
• electro-optical light sensor means at a predetermined location and means for periodically reading from said sensor means at a frame rate respective sets of electrical data which each represent a respective image of light intensity impinging on said sensor means;
• and means for directing light reflected from the contour onto said light sensing means;
• the improvement comprising wherein said pattern generating means includes means for selectively effecting oscillatory movement of said intensity pattern in a direction substantially perpendicular to a path of travel of light through said pattern generating means, said oscillatory movement being effected at a frequency which is an integer multiple of said frame rate of said sensor means.