System and method for generating enhanced density distribution in a three dimensional model of a structure for use in skeletal assessment using a limited number of two dimensional views

1. A computer implemented method of generating a density enhanced customized model of an object comprising:

generating a customized model of an object using a generic model of the object, the customized model comprising at least one volume element, the at least one volume element including density information;

generating a density map using a synthesized projection image of the customized model and a projection image of the object;

modifying the density information of the at least one volume element with information from the density map into the customized model to provide a density enhanced customized model of the object; and

performing at least one of storing the density enhanced customized model of the object and displaying the density enhanced customized model of the object on a user display.

2. The method of claim 1 , wherein modifying the density information of the at least one volume element with information from the density map into the customized model comprises back-projecting gains from the density map into the customized model.

3. The method of claim 1 , wherein the object comprises a bone, the density information is associated with a density of the bone.

4. The method of claim 3 , wherein the method further comprises determining a bone mass density (BMD) of the object using the density enhanced customized model of the object.

5. The method according to claim 1 , wherein generating a customized model of the object comprises:

selecting a standard model of a structure of a same type as the object, from a set of pre-defined three-dimensional models of structures, each standard model of each structure comprising a plurality of modes of deformation;

generating a synthesized image of the structure using the standard model, the synthesized image having an associated projection angle;

comparing a projection image of the object, taken at the associated projection angle, to the synthesized image to obtain a measurement of differences between the synthesized image and the projection image; and

modifying the standard model of the structure to generate a customized model of the object by selectively varying at least one mode of deformation of the standard model and repeating the steps of generating, comparing and modifying until the measurement of differences is within a desired threshold.

6. The method of claim 1 , wherein the density map comprises an M×N array of density value entries, and wherein generating a two-dimensional density map comprises:

generating a synthesized projection image of the customized model at a projection angle associated with the projection image of the object, the projection image and the synthesized projection image each comprising an M×N array of pixels; and

for each entry in the density map, storing a value associated with a relationship between a projection image pixel and a synthesized projection image pixel at similar locations in the respective synthesized projection image and the projection image.

7. The method of claim 6 , wherein the mathematical relationship is:

G (M,N) =DXA _ PI (M,N) /DRR (M,N) ,

wherein DXA_PI(M,N) is a first pixel intensity value of the projection image at location (M,N), and DRR(M,N) is a second pixel intensity value of the synthesized projection image at location (M,N).

8. A system for assessing characteristics of an object includes:

a processor;

a storage medium for storing a projection image of an object;

program code stored in the storage medium and operable when executed upon by the processor to:

generate a customized a model of the object using a generic model of the object and the projection image of the object, the customized model comprising at least one volume element, the at least one volume element including density information;

generate a density map using a synthesized projection image of the customized model and a projection image of the object; and

modify the density information of the at least one volume element with information from the density map into the customized model to provide a density enhanced customized model of the object and thereby transform the generic model of the object into an object specific model; and wherein the density enhanced customized model of the object is stored in the storage medium.

9. The system of claim 8 , wherein the program code stored in the storage medium and operable when executed by the processor to modify the density information of the at least one volume element with information from the density map into the customized model comprises the program code stored in the storage medium and operable when executed by the processor to back-project gains from the density map into the customized model.

10. The system of claim 8 , wherein the density map comprises an M×N array of density values and wherein the program code that is operable to generate a density map includes program code operable to:

generate a synthesized projection image of the customized model at a projection angle associated with the projection image of the object, the projection image and the synthesized projection image each comprising an M×N array of pixels; and

for each (M,N) entry in the density map, store a value associated with a relationship between a first image pixel at an (M,N) location of the projection image and a second image pixel at an (M,N) location of the synthesized projection image pixel.

11. The system of claim 10 , wherein the relationship is defined by the below equation:

G ( M,N )= DXA _ PI ( M,N/DRR ( M,N )

wherein DXA_PI(M,N) is a pixel intensity value of the projection image at location (M,N) and DRR(M,N) is the pixel intensity value of the synthesized projection image at location (M,N).