DETERMINING A LOAD STATUS OF A PLATFORM USING A LIKELIHOOD RATIO TEST

• US 20180137086A1
• Filed: 11/14/2016
• Published: 05/17/2018
• Est. Priority Date: 11/14/2016
• Status: Active Grant

• Current Assignee: Blackberry Limited
• Original Assignee: Blackberry Limited
• Inventors: Stolpman, Victor James, He, Dake
• Granted Patent: US 10,572,570 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01V 8/10 Detecting, e.g. by using light barriers by reflection from the object G01S17/00
• CPC Class Codes: G06F 17/18 for evaluating statistical data , e.g. average values, frequency distributions, probability functions, regression analysis forecasting specially adapted for a specific administrative, business or logistic context G06Q10/04
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: G06Q 10/083 Shipping

Abstract

In some examples, measurement data is received from at least one sensor that detects a signal reflected from a surface inside a platform. A likelihood ratio test is applied using the measurement data, and a load status of the platform is determined based on the likelihood ratio test.

Claims

1. A method performed by at least one processor, comprising:

receiving measurement data from at least one sensor that detects a signal reflected from a surface inside a platform;

applying a likelihood ratio test using the measurement data; and

determining a load status of the platform based on the likelihood ratio test.

2. The method of claim 1, wherein applying the likelihood ratio test comprises computing a value using an estimated baseline corresponding to an empty platform.

3. The method of claim 2, wherein applying the likelihood ratio test further comprises:

using the measurement data from the at least one sensor as a representation of a loaded platform;

comparing the computed value with respect to at least one threshold,

wherein determining the load status of the platform is based on the comparing.

4. The method of claim 3, wherein comparing the computed value with respect to the at least one threshold comprises comparing the computed value with respect to a first threshold and a second threshold, and wherein the determining comprises:

indicating that the platform is empty responsive to the computed value being less than the first threshold, and

indicating that the platform is loaded responsive to the computed value exceeding the second threshold.

5. The method of claim 1, wherein applying the likelihood ratio test comprises applying a log likelihood ratio test.

6. The method of claim 1, wherein applying the likelihood ratio test comprises:

computing a plurality of values using a likelihood ratio test function applied on corresponding samples of measurement data received from the at least one sensor;

aggregating the plurality of values to produce an aggregate value,

wherein determining the load status of the platform is based on the aggregate value.

7. The method of claim 6, wherein determining the load status of the platform is based on comparing the aggregate value to at least one threshold, wherein the aggregate value having a first relationship to the at least one threshold indicates that the platform is empty, and the aggregate value having a second relationship to the at least one threshold indicates that the platform is loaded.

8. The method of claim 7, further comprising:

computing the at least one threshold based on tuning parameters selected to control error rates.

9. The method of claim 1, wherein applying the likelihood ratio test comprises applying a generalized likelihood ratio test.

10. The method of claim 9, wherein applying the generalized likelihood ratio test comprises:

defining a subspace based on a phase;

identifying a point in the subspace that is closest to points representing measurement data received from the at least one sensor;

using the identified point as an estimated baseline corresponding to an empty platform;

computing a value using the estimated baseline.

11. The method of claim 10, wherein computing the value using the estimated baseline comprises computing the value using a log-likelihood ratio test or a sequential probability ratio test.

12. An apparatus comprising:

at least one sensor to output measurement data responsive to detecting a signal reflected from a surface inside a platform;

at least one processor configured to;

compute a value by applying a likelihood ratio test function on the measurement data; and

determine a load status of the platform based on the computed value.

13. The apparatus of claim 12, wherein the at least one sensor comprises a light detector to detect reflected light emitted by a light emitter.

14. The apparatus of claim 12, wherein the likelihood ratio test function is based on a ratio between a model representing an empty platform and a model representing a loaded platform.

15. The apparatus of claim 14, wherein the model representing the empty platform is based on a mean of measurement data samples representing the empty platform, and the model representing the loaded platform is based on a mean of measurement data samples representing the loaded platform.

16. The apparatus of claim 12, wherein the at least one processor is configured to:

compute a plurality of values output by applying the likelihood ratio test function on a plurality of measurement data samples from the at least one sensor; and

aggregate the plurality of values to produce an aggregate value,

wherein the determining of the load status is based on comparing the aggregate value to at least one threshold.

17. The apparatus of claim 12, wherein the at least one processor is configured to compare the computed value to at least one threshold, wherein the computed value having a first relationship to the at least one threshold indicates that the platform is empty, and the computed value having a second relationship to the at least one threshold indicates that the platform is loaded.

18. The apparatus of claim 12, wherein the at least one processor is configured to:

determine an estimated baseline corresponding to an empty platform by;

identifying a point in a subspace that is closest to points representing measurement data received from the at least one sensor, wherein the subspace corresponds to a specified phase in In-phase/Quadrature (IQ) space,

wherein the likelihood ratio test function is based on the estimated baseline.

19. A non-transitory machine-readable storage medium storing instructions that upon execution cause a system to:

receive measurement data from at least one sensor that detects a signal reflected from a surface inside a platform;

apply a likelihood ratio test using the measurement data, the likelihood ratio test producing an output value; and

determine a load status of the platform based on comparing the output value to at least one threshold.

20. The non-transitory machine-readable storage medium 19, wherein the determining comprises:

indicating that the platform is empty responsive to the output value having a first relationship with respect to the at least one threshold, and

indicating that the platform is loaded responsive to the output value having a second relationship with respect to the at least one threshold.

21. The non-transitory machine-readable storage medium 19, wherein the likelihood ratio test is selected from among a log-likelihood ratio test, a sequential probability ratio test, and a generalized likelihood ratio test.