Detection systems with spatial specificity and methods of detecting flame or gas with spatial specificity
A detection system includes a photodetector, a spatial light modulator (SLM) device optically coupled to the photodetector, and a controller. The controller is operatively connected to the SLM device and is disposed in communication with the photodetector and a memory. The memory has instructions recorded on the memory that cause the controller to communicate a SLM pattern sequence to the SLM device, modulate illumination incident on the SLM device according to the SLM pattern sequence to generate an illumination pulse sequence, and receive an intensity-time profile from the photodetector corresponding to the SLM pattern sequence. The instructions also cause the controller to signal, with spatial specificity, presence of flame or gas when the intensity-time profile indicates that flame or gas is present within a field of view of the detection system. Detection methods and computer program products are also described.
1 . A detection system, comprising:
a photodetector;
a spatial light modulator (SLM) device optically coupled to the photodetector; and
a controller operatively connected to the SLM device and disposed in communication with the photodetector, the controller configured to:
communicate a SLM pattern sequence to the SLM device;
modulate illumination incident on the SLM device according to the SLM pattern sequence to generate an illumination pulse sequence;
receive an intensity-time profile from the photodetector corresponding to the SLM pattern sequence; and
signal, with spatial specificity, presence of flame or gas when the intensity-time profile indicates that flame or gas is present within a field of view of the detection system;
wherein signalling the presence of flame or gas includes:
transposing the intensity-time profile into an intensity-position profile;
comparing the intensity-position profile to a reference intensity-position profile;
wherein the presence of flame or gas is signalled in response to the intensity-position profile being greater than the reference intensity-position profile at a common position by an amount greater than a predetermined threshold.
2 . The detection system as recited in claim 1 , wherein the photodetector comprises one and not more than one photodetector.
3 . The detection system as recited in claim 1 , wherein the photodetector comprises two or more photodetectors.
4 . The detection system as recited in claim 1 , wherein the photodetector comprises a photodiode, a photoresistor, a pyroelectric detector, or a thermopile.
5 . The detection system as recited in claim 1 , wherein the photodetector does not include a focal-plane array.
6 . The detection system as recited in claim 1 , wherein the photodetector is an infrared or an ultraviolet photodetector.
7 . The detection system as recited in claim 1 , wherein the SLM devices comprises a micro-mirror assembly, a coded aperture, or a liquid-crystal matrix.
8 . The detection system as recited in claim 1 , further comprising:
an imaging lens optically coupled to the SLM device; and
a focusing lens optically coupling the SLM device to the photodetector.
9 . The detection system as recited in claim 1 , wherein the controller is configured to provide an indication to a user interface when flame or gas is present within the field of view of the detection system.
10 . A detection method, comprising:
communicating a spatial light modulator (SLM) pattern sequence to a SLM device;
modulating illumination incident on the SLM device from a scene according to the SLM pattern sequence to generate an illumination pulse sequence;
receiving, at a controller, an intensity-time profile from a photodetector corresponding to the SLM pattern sequence, wherein a SLM device is optically coupled to the photodetector, wherein the controller is operatively connected to the SLM device and disposed in communication with the photodetector; and
signalling, with spatial specificity, presence of flame or gas when the intensity-time profile indicates that flame or gas is present within the scene;
wherein signalling the presence of flame or gas includes:
transposing the intensity-time profile into an intensity-position profile;
comparing the intensity-position profile to a reference intensity-position profile;
wherein the presence of flame or gas is signalled in response to the intensity-position profile being greater than the reference intensity-position profile at a common position by an amount greater than a predetermined threshold.
11 . The detection method as recited in claim 10 , further wherein the intensity-time profile is generated using infrared illumination.
12 . A non-transitory computer readable medium on which a computer program product is tangibly embodied, the computer program product including instructions that, when executed by a processor, cause the processor to perform operations comprising:
communicating a spatial light modulator (SLM) pattern sequence to a SLM device;
modulating illumination incident on the SLM device according to the SLM pattern sequence to generate an illumination pulse sequence;
receiving an intensity-time profile from the photodetector corresponding to the SLM pattern sequence; and
signalling, with spatial specificity, presence of flame or gas when the intensity-time profile indicates that flame or gas is present within a field of view of the detection system;
wherein signalling the presence of flame or gas includes:
transposing the intensity-time profile into an intensity-position profile;
comparing the intensity-position profile to a reference intensity-position profile;
wherein the presence of flame or gas is signalled in response to the intensity-position profile being greater than the reference intensity-position profile at a common position by an amount greater than a predetermined threshold.