System and method for man overboard incident detection

1. A method of detecting a man overboard event on a structure above a waterline, the method comprising the steps of:

providing first and second imaging devices, each having an angular field of view, wherein the angular fields of view of each of the first and second imaging devices overlap to establish a detection cuboid, the detection cuboid having:

a ceiling extending along an upper boundary common to the angular fields of view of the first and second imaging devices;

a base defined by the waterline; and

an inner boundary extending along a vertical plane which is registered with an outer edge of the structure;

contemporaneously recording first and second video streams, respectively, of the detection cuboid while the object is actively falling through the detection cuboid established by the overlap of the first and second imaging devices;

monitoring, in the detection cuboid established by the overlap of the first and second imaging devices, an object in both the first and second video streams while the object is actively falling along the structure and in the detection cuboid;

determining first and second characteristics of the object from the first and second video streams, respectively;

comparing the first and second characteristics and identifying a man overboard event in response to a conforming comparison;

determining a first range of the object from the first imaging device and a second range of the object from the second imaging device; and

determining a real-word location of the object from the first range, the second range, the angular fields of view of the first and second imaging devices, a real-world position of the structure, and a dimension of the object.

2. The method of claim 1 , wherein the step of comparing includes comparing the first characteristic from the first video stream to the second characteristic from the second video stream.

3. The method of claim 1 , wherein the step of comparing includes comparing the first and second characteristics from the first and second video streams with an expected characteristic.

4. The method of claim 1 , wherein the first and second characteristics include at least one of a height of the object, a width of the object, the first range of the object from the first imaging device, the second range of the object from the second imaging device, a velocity of the object, an acceleration of the object, a trajectory of the object, a segment of the trajectory of the object, and a position of the object.

5. The method of claim 1 , wherein the first imaging device has a first view volume and the second imaging device has a second view volume which overlaps the first view volume to define the detection cuboid.

6. The method of claim 5 , wherein the detection cuboid is limited vertically to extending between the waterline at the base and a lowest height from which a fall could originate from the structure at the ceiling.

7. The method of claim 1 , wherein the first and second imaging devices are thermal cameras.

8. The method of claim 1 , wherein the first and second imaging devices have larger angular fields of view in a vertical direction than in a horizontal direction.

9. The method of claim 1 , wherein the first and second imaging devices are oriented so that the first and second view volumes extend across an exterior surface of the structure.

10. The method of claim 1 , further comprising the step of transmitting an alarm, the alarm including portions of the first and second video streams including the man overboard event, a time of the man overboard event, and a location of the man overboard event.

11. A method of detecting a man overboard event on a structure above a waterline, having an exterior, and having a plurality of decks including a lowest deck, the method comprising the steps of:

providing first and second imaging devices, each having an angular field of view, and each contemporaneously recording first and second video streams, respectively, wherein the first imaging device has a first view volume, and the second imaging device has a second view volume which overlaps the first view volume to define a detection cuboid;

wherein the detection cuboid has an inner boundary which extends along a vertical plane which is registered with the outer edge of the structure, and the detection cuboid also extends between a ceiling, which is along an upper boundary common to the angular fields of view of the first and second imaging devices, and a base, which is defined by the waterline

monitoring, in the detection cuboid established by the overlap of the first and second imaging devices, and in both the first and second video streams simultaneously, an object actively falling along the structure and in the detection cuboid;

processing the first and second video streams;

identifying a man overboard event in response to an object in the detection cuboid having determined characteristics which conform to expected characteristics;

determining a first range of the object from the first imaging device and a second range of the object from the second imaging device; and

determining a real-world location of the object from the first range, the second range, the angular fields of view of the first and second imaging devices, a real-world position of the structure, and a dimension of the object.

12. The method of claim 11 , wherein the determined characteristics include at least one of a height of the object, a width of the object, a first range of the object from the first imaging device, a second range of the object from the second imaging device, a velocity of the object, an acceleration of the object, a trajectory of the object, a segment of the trajectory of the object, and a position of the object.

13. The method of claim 11 , wherein the first and second imaging devices have larger angular fields of view in a vertical direction than in a horizontal direction.

14. The method of claim 11 , wherein the detection cuboid is bound between the waterline and the lowest deck.

15. The method of claim 11 , wherein the first and second imaging devices are oriented so that the first and second view volumes extend across the exterior of the structure.

16. A system of detecting a man overboard event on a structure above a waterline, having an exterior, and having a plurality of decks including a lowest deck, the system comprising:

first and second imaging devices, each having an angular field of view, and each having first and second view volumes and configured to record first and second video streams of the first and second view volumes, respectively;

a detection cuboid established by an overlap of the first and second view volumes, wherein the detection cuboid has:

a height bound between the waterline and the lowest deck; and

an inner boundary which extends along a vertical plane which is registered with the outer edge of the structure; and

a computer coupled in data communication with the first and second imaging devices, the computer configured to contemporaneously process the first and second video streams and identify a man overboard event in response to an object actively falling along the structure in the detection cuboid and having determined characteristics which conform to expected characteristics;

wherein the computer is further configured to determine a real-world location of the object, such location determined from a first range of the object from the first imaging device, a second range of the object from the second imaging device, the angular fields of view of the first and second imaging devices, a real-world position of the structure, and a dimension of the object.

17. The system of claim 16 , wherein the first and second imaging devices are thermal cameras.

18. The system of claim 16 , wherein the first and second imaging devices have larger angular fields of view in a vertical direction than in a horizontal direction.

19. The system of claim 16 , wherein the first and second imaging devices are oriented so that the first and second view volumes extend across the exterior of the structure.

20. The system of claim 16 , wherein:

the first and second imaging devices are spaced apart from each other by an inter-camera distance;

the inter-camera distance is limited by a maximum range of the imaging devices; and

the maximum range is limited by a pixel-on-target minimum for the object in the detection cuboid.