Weight determination for objects moving past a fixed spot

1. A method performed by a mail processing system, comprising:

transporting a mail piece having a weight;

during transport, determining physical characteristics of the mail piece;

during transport, determining a density profile of the mail piece using an x-ray scanner;

determining the weight of the mail piece according to the physical characteristics and the density profile, by referencing a previously-stored weight classifier corresponding to the density profile, and using a weight associated with the previously-stored weight classifier as the determined weight; and

selectively separating the mail piece during transport based on the determined weight.

2. The method of claim 1 , the weight classifier includes physical characteristic data selected from extracted features, thickness profile data, and density profile data, and includes the weight associated with that classifier.

3. The method of claim 1 , wherein the mail processing system also determines a mail class associated with the mail piece based on the previously-stored weight classifier.

4. The method of claim 3 , wherein the mail processing system also determines whether the determined weight for the mail piece is over a weight threshold for a fee associated with the mail class.

5. The method of claim 1 , wherein determining the physical dimensions of the mail piece includes determining one or more physical dimensions of the mail piece from a visible light image of the mail piece.

6. The method of claim 1 , wherein the x-ray scanner is a low-power x-ray scanner with a single point sensor.

7. The method of claim 1 , wherein the mail piece is selectively separated when the weight for the mail piece over a weight threshold associated with the mail piece.

8. The method of claim 1 , wherein the separated mail piece is physically weighed to determine a measured weight, and the mail processing system uses the measured weight to update a weight classifier corresponding to the mail piece.

9. The method of claim 1 , wherein the mail processing system records variations in density across the mail piece, derives density variation features from these variations, and uses the density variation features for the density profile.

10. A mail processing system, comprising:

at least one processor;

an accessible memory; and

a plurality of mail processing devices; the mail processing system configured to transport a mail piece having a weight, and during transport, to:

determine physical characteristics of the mail piece;

determine a density profile of the mail piece using an x-ray scanner;

determine the weight of the mail piece according to the physical characteristics and the density profile, by referencing a previously-stored weight classifier corresponding to the density profile, and using a weight associated with the previously-stored weight classifier as the determined weight; and

selectively separate the mail piece during transport based on the determined weight.

11. The mail processing system of claim 10 , wherein the weight classifier includes physical characteristic data selected from extracted features, thickness profile data, and density profile data, and includes the weight associated with that classifier.

12. The mail processing system of claim 10 , wherein the mail processing system also determines a mail class associated with the mail piece based on the previously-stored weight classifier.

13. The mail processing system of claim 12 , wherein the mail processing system also determines whether the determined weight for the mail piece is over a weight threshold for a fee associated with the mail class.

14. The mail processing system of claim 10 , wherein determining the physical dimensions of the mail piece includes determining one or more physical dimensions of the mail piece from a visible light image of the mail piece.

15. The mail processing system of claim 10 , wherein the mail piece is selectively separated when the weight for the mail piece over a weight threshold associated with the mail piece.

16. The mail processing system of claim 10 , wherein determining the physical dimensions of the mail piece includes determining a density profile of the mail piece, and the density profile is used to determine the weight by referencing a stored weight classifier.

17. The mail processing system of claim 10 , wherein the separated mail piece is physically weighed to determine a measured weight, and the mail processing system uses the measured weight to update a weight classifier corresponding to the mail piece.

18. The mail processing system of claim 10 , wherein the mail processing system records variations in density across the mail piece, derives density variation features from these variations, and uses the density variation features for the density profile.

19. A non-transitory computer readable medium having program instructions stored thereon executable by one or more processors to:

transport a mail piece having a weight;

determine physical characteristics of the mail piece;

determine a density profile of the mail piece using an x-ray scanner;

determine the weight of the mail piece according to the physical characteristics and the density profile, by referencing a previously-stored weight classifier corresponding to the density profile, and using a weight associated with the previously-stored weight classifier as the determined weight; and

selectively separate the mail piece during transport based on the determined weight.

20. The computer-readable medium of claim 19 , wherein the instructions are also executable by the one or more processors to determine a mail class associated with the mail piece based on the stored weight classifier and to determine whether the determined weight for the mail piece is over a weight threshold for a fee associated with the mail class.

21. A method performed by a mail processing system, comprising:

transporting a mail piece having a weight;

during transport, determining a density profile of the mail piece using an x-ray scanner, the density profile comprising a plurality of pixels;

determining the weight of the mail piece by summing all of the pixels in the density profile and multiplying by a calibrating weight factor that is stored as part of a previously-stored weight classifier; and

selectively diverting the mail piece during transport based on the determined weight.