Method for detecting a source of heat near a marine vessel
View Patent ↗Two sensor units are mounted on opposite sides of a transom of a boat and directed to a common location behind the boat. The field of view of the two sensors overlaps behind the marine propulsion unit of the boat to detect the presence of a heat emitting object, such as a mammal. Housing structures contain infrared sensing elements, lenses, and light shields. Signals from four infrared sensing elements are received by a controller which reacts, with an alarm signal, when at least two of the four sensors detect a heat emitting object within their individual fields of view. False triggering can be reduced by not providing an alarm signal if only the two most inboard sensors detect the heat emitting object.
1. A method for detecting a heat source proximate a marine vessel, comprising the steps of:
monitoring a first field of view in a first direction from a first sensing device;
providing a first signal when a heat source is within said first field of view;
monitoring a second field of view in a second direction from a second sensing device;
providing a second signal when a heat source is within said second field of view;
receiving said first and second signals; and
determining the presence or absence of a heat source within a detection zone as a function of both of said first and second signals, said first sensing device comprising a first sensor and a second sensor, said second sensor being disposed closer to a centerline of said marine vessel than said first sensor, said second sensing device comprising a third sensor and a fourth sensor, said third sensor being disposed closer to said centerline of said marine vessel than said fourth sensor, said first, second, third, and fourth sensors being each configured to provide an individual signal representing the detection of said heat source within its individual field of view;
providing an alarm signal in response of receipt of individual signals from at least one of said first, second, third, and fourth sensors; and
refraining from providing said alarm signal in response to receipt of individual signals from only said second and third sensors.
2. The method of claim 1 , wherein:
said first sensing device contains a first infrared device; and
said second sensing device contains a second infrared device.
3. The method of claim 1 , wherein:
said first and second sensing devices are attached to said marine vessel with said first and second fields of view directed in a rearward direction, said detection zone being defined by an intersection of said first and second fields of view which is located a preselected distance behind said marine vessel.
4. The method of claim 1 , wherein:
said first sensing device is attached to a starboard side of a rearward portion of said marine vessel; and
said second sensing device is attached to a port side of said rearward portion of said marine vessel.
5. The method of claim 1 , further comprising: providing said alarm signal in response to receipt of individual signals from at least two of said first, second, third, and fourth sensors.
6. The method of claim 1 , further comprising: providing said alarm signal in response to receipt of individual signals from said first and second sensors, said first and third sensors, said first and fourth sensors, said second and fourth sensors, or said third and fourth sensors.
7. A method for detecting a heat source proximate a marine vessel, comprising the steps of:
monitoring a first field of view in a first direction from a first sensing device;
providing a first signal when a heat source is within said first field of view;
monitoring a second field of view in a second direction from a second sensing device, said first and second sensing devices being attached to said marine vessel with said first and second fields of view directed in a rearward direction, said first and second fields of view intersecting at a detection zone behind said marine vessel, said first sensing device comprising a first sensor and a second sensor, said second sensing device comprising a third sensor and a fourth sensor;
providing a second signal when a heat source is within said second field of view;
receiving said first and second signals; and
determining the presence or absence of a heat source within said detection zone as a function of both of said first and signals, said second sensor being disposed closer to a centerline of said marine vessel than said first sensor and said third sensor being disposed closer to said centerline of said marine vessel than said fourth sensor, said first, second, third, and fourth sensors being each configured to provide individual signals representing the detection of said heat source within its individual field of view;
providing an alarm signal in response of receipt of individual signals from at least one of said first, second, third, and fourth sensors; and
refraining from providing said alarm signal in response to receipt of individual signals from only said second and third sensors.
8. The method of claim 7 , further comprising: providing said alarm signal in response to receipt of individual signals from two or more of said first, second, thirds, and fourth sensors.
9. The method of claim 7 , further comprising: providing said alarm signal in response to receipt of individual signals from said first and second sensors, said first and third sensors, said first and fourth sensors, said second and fourth sensors, or said third and fourth sensors.