Background:

Coloring 3D models may either be done manually using computer graphic software or automatically by assigning color information using texture mapping from 2D images. Texturing 3D models using casual images taken from an arbitrary source (like personal album or the internet) can be highly beneficial. However, the known methods lack the ability to avoid dissimilarities (as pose and proportions) between the photographed object and the 3D model, and therefore casual images can not be used. For instance, painting a model of a man using one’s personal photograph is hard to achieve using current methods, which mostly use a "constrained parameterization". This approach tends to introduce high distortions in the textured model, since the photography effects (effects of camera projection, viewpoint and object 3-dimensionalty) are ignored. These distortions can be highly visible. Overcoming these distortions, if possible, requires a lot of time and efforts.

Method:

Our method uses as input a 3D model, a casual image (where the photographed object might have different proportions from the target 3d model), and a small set of constraints defined manually (pairs of corresponding points in the model and the image). It then formulates the mapping as a camera projection matrix. Rather then estimating a single camera projection to the entire model, a different local camera is computed for each vertex of the model, by weighting the constraints differently; Then, The visible model regions are detected in the image, and colored according to the mapping.
By formulating the mapping as a camera projection matrix, distortions are avoided and easy coloring of the 3D model is achieved.

Advantages:

• Enabling the use of casual 2D images that cannot be used by other approach to color 3D models.
• Leading to create minimum distortions in the model, caused by camera effects.
• Easy to use by a non-expert user.

Applications:

• Plug-in for a professional modeling software (e.g. 3D Studio, Maya).
• Avatar and Character creation in computer games and in social networks.
• Modeling to be used in military simulations.

Technological Keywords: Texture mapping, 3d models, avatars, military simulations, computer graphics, social networks
Market Keywords: computer graphics, computer games, virtual worlds