REDUCING LATENCY IN A DETECTION SYSTEM

• US 20090034792A1
• Filed: 08/01/2008
• Published: 02/05/2009
• Est. Priority Date: 08/02/2007
• Status: Active Grant

• Current Assignee: L3 Security & Detection Systems, Inc. (Leidos Holdings, Inc.)
• Original Assignee: L-3 Communications Security & Detection Systems, Inc. (Leidos Holdings, Inc.)
• Inventors: Donasch, Ingo, Kennison, Justin, Connelly, James
• Granted Patent: US 8,331,675 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G01V 5/22 Active interrogation, i.e. by irradiating objects or goods using external radiation sources, e.g. using gamma rays or cosmic rays
• CPC Class Codes: G06T 9/00 Image coding bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00

Abstract

A first multi-dimensional digital image of a scan region is generated. The scan region is included in a materials-detection apparatus and is configured to receive and move containers through the materials-detection apparatus. A pre-defined background range of values is accessed, the background range of values representing a range of values associated with non-target materials and the background range of values being distinct from values associated with the target materials. A value of a voxel included in the multi-dimensional digital image is compared to the background range of values to determine whether the value of the voxel is within the background range of values. If the value of the voxel is within the background range of values, the voxel is identified as a voxel representing a low-density material. A second multi-dimensional digital image that disregards the identified voxel is generated to compress the first multi-dimensional digital image.

Claims

1. A computer-implemented method of compressing data in a materials-detection system, the method comprising:

generating a first multi-dimensional digital image of a scan region, the scan region being included in a materials-detection apparatus and being configured to receive and move containers through the materials-detection apparatus;

accessing a pre-defined background range of values, the background range of values representing a range of values associated with non-target materials and the background range of values being distinct from values associated with the target materials;

comparing a value of a voxel included in the multi-dimensional digital image to the background range of values to determine whether the value of the voxel is within the background range of values;

if the value of the voxel is within the background range of values, identifying the voxel as a voxel representing a low-density material; and

generating a second multi-dimensional digital image that disregards the identified voxel to compress the first multi-dimensional digital image.

2. The method of claim 1, wherein generating a second multi-dimensional digital image comprises generating a second multi-dimensional digital image that excludes the identified voxel.

3. The method of claim 2 further comprising generating a mapping that represents the location of the identified voxel relative to other voxels included in the first multi-dimensional digital image.

4. The method of claim 1, wherein generating a second multi-dimensional digital image comprises generating a second multi-dimensional digital image that replaces the value of the identified voxel with a pre-defined value.

5. The method of claim 1 further comprising analyzing the second multi-dimensional digital image for target materials without analyzing the disregarded voxel.

6. The method of claim 1, wherein the background range comprises a subset of the ranges for non-target materials.

7. The method of claim 1, wherein the non-target material comprises air and air-like materials.

8. The method of claim 1, wherein:

the scan region includes a container that includes non-target materials and target materials, and

the image of the scan region includes voxels representing the entire container, voxels representing the non-target items, and voxels representing the target materials.

9. The method of claim 1, wherein the target materials comprise one or more of explosives and controlled substances.

10. The method of claim 1 further comprising:

transferring the second multi-dimensional digital image across a network to a processor remote from the explosives-detection apparatus; and

analyzing the second multi-dimensional digital image for the presence of target materials.

11. The method of claim 10, wherein analyzing the second multi-dimensional digital image for the presence of target materials comprises analyzing a visual presentation of the second multi-dimensional digital image for the presence of target materials.

12. The method of claim 1, wherein the first multi-dimensional digital image includes a representation of a container and further comprising:

identifying a contiguous segment in the first multi-dimensional digital image as a segment that includes voxels representing a non-target material outside of the container, the segment being bound by a boundary representing an interface between the non-target material outside of the container and an edge of the container;

generating a pointer in the first multi-dimensional digital image, the pointer referring to the boundary;

transferring the pointer over a network to a processor remote from the explosives-detection apparatus;

receiving a request from the remote processor for a portion of the first multi-dimensional digital image referred to by the pointer, the portion including the representation of the container; and

transferring the portion of the first multi-dimensional digital image over the network to the remote processor.

13. The method of claim 1, wherein the scan region comprises a tunnel sized to accommodate luggage and hand-carried packages.

14. The method of claim 1, wherein the scan region comprises a region configured to receive cargo.

15. The method of claim 1, further comprising:

compressing the second multi-dimensional image with a non-lossy compression technique; and

generating a third multi-dimensional image from the compressed second multi-dimensional image.

16. The method of claim 1, wherein the scan region includes a container and air surrounding the container.

17. The method of claim 1 further comprising determining whether the scan region includes a container before generating the first multi-dimensional image.

18. An materials-detection system having a reduced latency, the system comprising:

a screening apparatus comprising;

a scan region configured to receive and move containers through the screening apparatus,

an imaging system configured to produce a first multi-dimensional digital image of the scan region, the first multi-dimensional digital image including voxels,

a latency reduction module configured to compress the first multi-dimensional digital image of the receiving region, the latency reduction module being configured to;

receive the first multi-dimensional digital image of an air-filled region,

access a pre-defined background range of values, the background range of values representing a range of values associated with non-target materials and the background range of values being distinct from values associated with target materials,

compare a value of a voxel included in the multi-dimensional digital image to the background range of values to determine whether the value of the voxel is within the background range of values,

if the value of the voxel is within the background range of values, identify the voxel as a voxel representing a non-target material, and

generate a second multi-dimensional digital image that disregards the identified voxel to compress the first multi-dimensional digital image; and

an analysis station configured to;

receive the second multi-dimensional digital image, and

present the second multi-dimensional digital image.

19. A computer-implemented method of reducing latency in a materials-detection system, the method comprising:

accessing a multi-dimensional digital image of a scan region that includes an item of interest and a second item, the multi-dimensional digital image including voxels and the scan region being included in a materials-detection apparatus and being configured to receive and move containers through the materials-detection apparatus;

analyzing the voxels included in the multi-dimensional digital image to identify portions of the multi-dimensional digital image that have characteristics of items of interest;

selecting the identified portions of the multi-dimensional digital image that have characteristics of the items of interest;

transferring the selected portions over a network before transferring unselected portions; and

presenting the selected portions before enabling presentation of the unselected portions.

20. The method of claim 19, wherein:

the items of interest include a contraband item, and

analyzing the voxels included in multi-dimensional digital image to identify portions of the multi-dimensional digital image that have characteristics of items of interest comprises analyzing the voxels to identify a portion of the multi-dimensional digital image having characteristics associated with the contraband item.

21. The method of claim 20 further comprising:

analyzing the identified portions of the multi-dimensional digital image;

determining a measure of confidence that a particular identified portion includes a representation of a contraband item; and

prioritizing the identified portion relative to other identified portions based on the measure of confidence.

22. The method of claim 20, wherein a contraband item includes an explosive material.

23. The method of claim 19, wherein selecting the identified portions comprises prioritizing the identified portions relative to portions of the multi-dimensional digital image that include representations of innocuous items and portions of the multi-dimensional digital image that include representations of air.

24. The method of claim 19 further comprising:

identifying a region surrounding an item of interest; and

transferring the region surrounding the item of interest over the network with a portion of the multi-dimensional digital image that includes the item of interest.

25. The method of claim 19, wherein:

identifying portions of the multi-dimensional digital image that have characteristics of items of interest comprises identifying a first portion of the multi-dimensional digital image that includes a representation of an item of interest before identifying a second portion of the multi-dimensional digital image that includes a representation of a second item of interest, and

transferring the identified portions based on the prioritization comprises transferring the first portion of the multi-dimensional digital image before identifying the second portion of the multi-dimensional digital image.

26. The method of claim 19 further comprising transferring the multi-dimensional digital image of the region over the network after transferring the identified portions.

27. The method of claim 26, further comprising displaying the identified portions, and wherein:

transferring the multi-dimensional digital image of the region and the identified portions comprises transferring the multi-dimensional digital image of the region and the identified portions to a remote processor,

transferring the multi-dimensional digital image of the region after transferring the identified portions comprises transferring the multi-dimensional digital image of the region in the background while displaying the identified portions.

28. The method of claim 19, wherein the second item is an item not of interest.

29. A materials-detection system having a reduced latency, the system comprising:

a screening apparatus comprising;

a scan region configured to receive and move containers through the screening apparatus,

an imaging system configured to produce a multi-dimensional digital image of the scan region, the multi-dimensional digital image including voxels,

a detection module configured to;

analyze the multi-dimensional image to identify portions of the multi-dimensional image that have characteristics of items of interest; and

a latency reduction module configured to;

select the identified portions of the multi-dimensional digital image that have characteristics of the items of interest, and

transfer the selected portions over a network before transferring unselected portions; and

an analysis station configured to;

receive the selected portions, and

present the selected portions before enabling presentation of the unselected portions.