Systems and Methods for Detecting Contraband

1 . A method for detecting contraband, said method comprising:

acquiring tomographic image data of a subject at a plurality of frequencies using low frequency electromagnetic tomography;

generating a composite image of the subject at each of the plurality of frequencies using the acquired tomographic image data;

determining a differentiation parameter for a tissue material at each of the plurality of frequencies;

determining a differentiation parameter for a non-tissue material at each of the plurality of frequencies;

decomposing the composite images into a tissue image and a non-tissue image using the determined differentiation parameters, wherein the tissue image contains any region of the subject composed of the tissue material and the non-tissue image contains any region of the subject composed of the non-tissue material; and

determining whether the non-tissue image contains any non-tissue material.

2 . A method in accordance with claim 1 , wherein determining a differentiation parameter for a non-tissue material comprises determining differentiation parameters for a finite set of non-tissue materials.

3 . A method in accordance with claim 1 , further comprising generating an alert if the non-tissue image contains any non-tissue material.

4 . A method in accordance with claim 1 , wherein acquiring tomographic image data comprises acquiring tomographic image data of the body cavity of a subject, and wherein determining whether the non-tissue image contains any non-tissue material comprises determining whether the body cavity contains any non-tissue material.

5 . A method in accordance with claim 1 , wherein acquiring tomographic image data comprises actively detecting a phase shift between an emitted electric field and a detected electric field.

6 . A method in accordance with claim 1 , wherein determining whether the non-tissue image contains any non-tissue material comprises analyzing an intensity of pixels in the non-tissue image.

7 . A method in accordance with claim 6 , wherein analyzing an intensity of pixels in the non-tissue image comprises determining whether a mean intensity value of pixels in the non-tissue image is above a threshold value.

8 . A security scanner configured to detect contraband, said security scanner comprising:

a detector array configured to acquire tomographic image data of a subject at a plurality of frequencies using low frequency electromagnetic tomography; and

a processing device coupled to said detector array and configured to:

generate a composite image of the subject at each of the plurality of frequencies using the acquired tomographic image data;

determine a differentiation parameter for a tissue material at each of the plurality of frequencies;

determine a differentiation parameter for a non-tissue material at each of the plurality of frequencies;

decompose the composite images into a tissue image and a non-tissue image using the determined differentiation parameters, wherein the tissue image contains any region of the subject composed of the tissue material and the non-tissue image contains any region of the subject composed of the non-tissue material; and

determine whether the non-tissue image contains any non-tissue material.

9 . A security scanner in accordance with claim 8 , wherein to determine a differentiation parameter for a non-tissue material, said processing device is configured to determine differentiation parameters for a finite set of non-tissue materials.

10 . A security scanner in accordance with claim 8 , wherein said processing device is further configured to generate an alert if the non-tissue image contains any non-tissue material.

11 . A security scanner in accordance with claim 8 , wherein to acquire tomographic image data, said detector array is configured to acquire tomographic image data of a body cavity of the subject.

12 . A security scanner in accordance with claim 8 , wherein said detector array is configured to acquire tomographic image data by actively detecting a phase shift between an emitted electric field and a detected electric field.

13 . A security scanner in accordance with claim 8 , wherein to determine whether the non-tissue image contains any non-tissue material, said processing device is configured to analyze an intensity of pixels in the non-tissue image.

14 . A security scanner in accordance with claim 13 , wherein to analyze an intensity of pixels in the non-tissue image, said processing device is configured to determine whether a mean intensity value of pixels in the non-tissue image is above a threshold value.

15 . One or more computer-readable storage media having computer-executable instructions embodied thereon for scanning a subject for contraband, wherein when executed by at least one processor, the computer-executable instructions cause the at least one processor to:

instruct a detector array to acquire tomographic image data of the subject at a plurality of frequencies using low frequency electromagnetic tomography;

generate a composite image of the subject at each of the plurality of frequencies using the acquired tomographic image data;

determine a differentiation parameter for a tissue material at each of the plurality of frequencies;

determine a differentiation parameter for a non-tissue material at each of the plurality of frequencies;

decompose the composite images into a tissue image and a non-tissue image using the determined differentiation parameters, wherein the tissue image contains any region of the subject composed of the tissue material and the non-tissue image contains any region of the subject composed of the non-tissue material; and

determine whether the non-tissue image contains any non-tissue material.

16 . One or more computer-readable storage media in accordance with claim 15 , further comprising computer executable-instructions that cause the at least one processor to generate an alert if the non-tissue image contains any non-tissue material.

17 . One or more computer-readable storage media in accordance with claim 15 , wherein to generate a composite image of the subject, said one or more computer-readable storage media comprise computer executable-instructions that cause the at least one processor to generate a composite image of a body cavity of the subject at the plurality of frequencies.

18 . One or more computer-readable storage media in accordance with claim 15 , wherein to instruct a detector array to acquire tomographic image data, said one or more computer-readable storage media comprise computer executable-instructions that cause the at least one processor to instruct the detector array to actively detect a phase shift between an emitted electric field and a detected electric field.

19 . One or more computer-readable storage media in accordance with claim 15 , wherein to determine whether the non-tissue image contains any non-tissue material, said one or more computer-readable storage media comprise computer executable-instructions that cause the at least one processor to analyze an intensity of pixels in the non-tissue image.

20 . One or more computer-readable storage media in accordance with claim 19 , wherein to analyze an intensity of pixels in the non-tissue image, said one or more computer-readable storage media comprise computer executable-instructions that cause the at least one processor to determine whether a mean intensity value of pixels in the non-tissue image is above a threshold value.