Apparatus and method for optimizing detection of objects in computed tomography data

Claims

What is claimed is:

1. A method of measuring and adjusting the performance of a system for detecting objects in computed tomography (CT) data for a region, said method comprising:

defining at least two different types of objects for selective detection, wherein at least one of the types of objects is a type of threat object;

defining at least two algorithms respectively related to the detection of the corresponding types of objects so that all of the algorithms form a part of a detection system;

defining (i) for each object type an object detection rate related to the probability of the system detecting the corresponding object type, and (ii) an overall system detection rate related to a combination of the object detection rates; and

modifying at least one algorithm so as to adjust at least one of the object detection rates and adjust the overall system, detection rate;

wherein the object detection rates of the object types are interdependent, the performance of the system is measured by the object detection rates and overall system detection rate, acceptable performance requires each of the object detection rates to be above a first predetermined threshold, and the overall system detection rate to be above a second predetermined threshold, and the overall system detection rate can be adjusted to achieve a predetermined level of performance by modifying at least one algorithm so as to adjust at least one of the object detection rates.

2. The method of claim 1 wherein at least one of the types of objects is a type of explosive.

3. The method of claim 1 wherein the types of objects are respectively different types of threat objects.

4. The method of claim 1 wherein the types of objects are respectively different types of explosives.

5. The method of claim 1 wherein the region includes at least a portion of an interior of a container.

6. The method of claim 5 wherein the container is a piece of baggage.

7. The method of claim 1 wherein the overall system detection rate is an average of the object detection rates.

8. The method of claim 1, wherein each algorithm exhibits an object false alarm rate relativity the probability of the algorithm mistakenly detecting objects as the corresponding object type, and all of the algorithms exhibit an overall system false alarm rate related to a combination of all of the object false alarm rates; and

further comprising the step of modifying at least one of the algorithms so as to adjust at least one of the object false alarm rates so as to adjust the overall system false alarm rate;

wherein the object false alarm rates are interdependent, the performance of the system is measured by the object false alarm rate, and overall system false alarm rate, and the overall system false alarm rate can be adjusted to achieve a predetermined level of performance by modifying at least one of the algorithms so as to adjust at least one of the object false alarm rates.

9. The method of claim 8 wherein the overall system false alarm rate is a sum of the object false alarm rates.

10. A method of measuring and adjusting the performance of a system for detecting objects in computed tomography (CT) data for a region, said method comprising:

defining at least two different types of objects for selective detection wherein at least one of the types of objects is a type of threat object;

defining at least two algorithms respectively related to the detection of the corresponding types of objects so that all of the algorithms form a part of a detection system;

defining for each object type an object false alarm rate related to the probability of the algorithm related to the detection of the corresponding object type mistakenly detecting objects as the corresponding object type, and an overall system false Alan rate related to a combination of the object false alarm rates; and

modifying at least one algorithm so as to adjust at least one of the object false alarm rates so as to adjust the overall system false alarm rate;

wherein the false alarm rates are interdependent, the performance of the system is measured by the object false alarm rates and overall system false alarm rate, and the overall system false alarm rate can be adjusted to achieve a predetermined level of performance by modifying at least one of the algorithms so as to adjust at least one of the object false alarm rates.

11. The method of claim 10 wherein at least one of the types of objects is a type of explosive.

12. The method of claim 10 wherein the types of objects are respectively different types of treat objects.

13. The method of claim 10 wherein the types of objects are respectively different types of explosives.

14. The method of claim 10 wherein the region includes at least a portion of an interior of a container.

15. The method of claim 14 wherein the container is a piece of baggage.

16. The method of claim 10 wherein the overall system false alarm rate is a sum of the object false alarm rates.

17. An apparatus for measuring and adjusting the performance of a system for detecting objects in computed tomography (CT) data for a region, said apparatus comprising:

an object selector constructed and arranged so as to define at least two different types of objects for selective detection, wherein at least one of the types of objects is a type of threat object;

at least two object detection algorithmic subsystems respectively related to the detection of the corresponding types of objects so that all of the algorithmic subsystems form a part of a detection system;

detection rate defining subsystem defining (i) for each of type of object an object detection rate related to the probability of the system detecting the corresponding object type, and (ii) an overall system detection rate related to a combination of the object detection rates; and

an object detection algorithmic subsystem modifier constructed and arranged so that at least one object detection algorithmic subsystem can be modified so as to change the corresponding object detection rate of the corresponding object type and adjust the overall system detection rate;

wherein the object detection rates are interdependent, the performance of the system is measured by the object detection rates and overall system detection rate, acceptable performance requires each of the object detection rates to be above a first predetermined threshold, and the overall system detection rate to be above a second predetermined threshold, and the overall system detection rate can be adjusted to achieve a predetermined level of performance by modifying at least one algorithmic subsystem so as to adjust at least one of the object detection rates.

18. The apparatus of claim 17 wherein at least one of the types of objects is a type of explosive.

19. The apparatus of claim 17 wherein the types of objects are respectively different types of threat objects.

20. The apparatus of claim 17 wherein the types of objects are respectively different types of explosives.

21. The apparatus of claim 17 wherein the region includes at least a portion of an interior of a container.

22. The apparatus of claim 21 wherein the container is a piece of baggage.

23. The apparatus of claim 17 wherein the overall system detection rate is an average of the object detection rates.

24. The apparatus of claim 17, wherein each object detection algorithmic subsystem exhibits (a) an object false alarm rate relating to the probability of the object detection algorithmic subsystem mistakenly detecting objects as the corresponding object type, and (b) an overall system false alarm rate related to