Mechanism and apparatus for realistic 3D model creation using interactive scissors

Abstract

A 3 D surface is defined in terms of a set of vertices. The 3 D surface and a pixel array are used to generate a 3 D image. Portions of the 3 D surface are selectively removed using selected criteria. In one embodiment, the 3 D surface is defined in terms of a set of triangles, and the triangles are tested for compliance with selected conditions. For example, the triangles can be tested to determine their slope. Based on these tests, the triangles are excised from the geometric surface. In one embodiment, the selected conditions are based on a combination of the slope of the triangles and the color of the pixels bound to the triangles.

We claim:  
     
         1 . A method comprising the steps of: 
 providing a model of a geometric surface, said model comprising a set of portions of said geometric surface, said model being stored in a memory device; and    excising at least some of said portions of said geometric surface in response to the slope of said some of said portions.    
     
     
         2 . Method of  claim 1  further comprising the step of binding an array of color values to said geometric surface and displaying an image corresponding to said color values and said geometric surface on a visual display device.  
     
     
         3 . Method of  claim 1  wherein said model comprises a plurality of polygons.  
     
     
         4 . Method of  claim 3  wherein said polygons are excised in accordance with the formula  
         Max ( A 0 , A 1 , . . . An )− Min ( A 0 , A 1 , . . . An )< e    
       where Max(A 0 , A 1 , . . . An) is the largest coordinate value of any of the polygon vertex coordinates along an axis, Min(A 0 , A 1 , . . . An) is the smallest z coordinate value of any of the polygon vertex coordinates along said axis, and e is a threshold value.  
     
     
         5 . Method of  claim 4  wherein said axis is the Z axis.  
     
     
         6 . Method of  claim 3  wherein said polygons are excised in accordance with the formula:  
         a   i   <Max ( A 0 ,A 1 ,. . . An )− Min ( A 0 ,A 1 ,. . . An ) <b   i   
       where Max(A 0 , A 01 , . . . An) is the largest coordinate value of any of the polygon vertex coordinates along an axis, Min(A 0 , A 1 , . . . An) is the smallest coordinate value of any of the polygon vertex coordinates along said axis, and a i  and b i  constitute a range of values  
     
     
         7 . Method of  claim 6  wherein said axis is the Z axis.  
     
     
         8 . Method of  claim 6  wherein a i  and b i  are functions of the color of pixels bound to the polygon.  
     
     
         9 . Method comprising the steps of 
 providing a model of a geometric surface, said model comprising a set of portions of said geometric surface, said model being stored in a memory;    binding an array of values to said geometric surface; and    excising at least some of said portions of said geometric surface based on the values bound to said portions of said geometric surface.    
     
     
         10 . Method of  claim 9  wherein said array of values is a pixel array containing values corresponding a color to be applied to said geometric surface.  
     
     
         11 . Method of  claim 9  wherein said array of values contains information corresponding to the luminance to be applied to said geometric surface.  
     
     
         12 . Method of  claim 9  wherein said array of values indicates depth values relating to the position of said geometric surface.  
     
     
         13 . Method of  claim 9  wherein said step of excising is also performed based on the slope of said geometric surface.  
     
     
         14 . Apparatus comprising: 
 a memory for storing values corresponding to a model of a geometric surface; and    means for excising portions of said geometric surface based on the slope of said portions.    
     
     
         15 . Apparatus of  claim 14  wherein said means for excising comprises a microprocessor.  
     
     
         16 . Apparatus comprising: 
 a memory for storing values corresponding to a model of a geometric surface; and    a memory for storing an array containing values bound to said geometric surface; and    means for excising portions of said geometric surface in response to values stored within said memory.    
     
     
         17 . Method comprising: 
 providing a model of a geometric surface, said model comprising a set of portions of said geometric surface, said model being stored in a memory device;    providing an array containing values; and    excising at least some of said portions of said geometric surface in response to said values.    
     
     
         18 . Method of  claim 17  wherein said array contains values indicating depth information of an image.  
     
     
         19 . Method of  claim 18  wherein said depth information is used to modify said model of said geometric surface.  
     
     
         20 . Method of  claim 17  wherein said array contains luminance information.  
     
     
         21 . Method of  claim 17  wherein said array contains color information.