Fire Detectors in Orbit
Wildfires are a growing global problem exemplified by the destruction in Los Angeles in January of this year. Photonics technologies offer some hope for early detection and mitigation using satellite-based Earth observation (EO).
The application of EO to early remote detection of wildfires typically offers two key approaches. First, observers can attempt to identify chemical absorption bands of interest, such as potassium, that can be indicative as precursors to wildfire. More common is the use of thermal imaging to look for hot spots, or specific types of heat profile, in long-wavelength infrared (LWIR) bands from space.
Multispectral imaging systems can combine these approaches into one unit. There is an advantage to comparing signals from different wavelength bands, or emission lines, to distinguish between “normal” situations and undesirable ones, as well as to confirm the presence of a wildfire.
To achieve multiband detection, one can place a multizone filter on top of a detector, in close proximity to where each zone of the filter will transmit a particular wavelength region onto the detector surface. For example, a multizone optical filter may have several strips of filters split between wavelength regions in the visible spectrum, as well as mid-wavelength infrared (MWIR) and LWIR bands. Each strip, or zone, usually translates into a different gas/element/constituent being detected. However, the detector is a fixed area, so the more zones in that area, the narrower the band, and the fewer pixels assigned to each one — which can limit the signal relative to the background for each band.
Check out an article from Iridian Spectral Technologies that explores this topic and the role optical filters play in enabling these detection technologies.
About Iridian Spectral Technologies
Iridian Spectral Technologies is a diversified optical filter manufacturer that is an international leader in filter design and manufacture especially for application in the fields of fiber optic communications, biomedical optical spectroscopy, 3D entertainment, and aerospace. Iridian draws on more than two decades of experience to provide:
- Bandpass filters
- Edge pass filters
- Gain flattening filters
- Notch filters
- Multi-zone filters (MZF)
- Custom filters
- Dichroic filters and beam splitters
- LaseReflect® LRG glasses
- Stray light (black) absorbers
- Etalons
- Linear transmittance filters (LTF)
- Tap couplers
To request more information or a quotation for Iridian products, contact IL Photonics.