| 摘要 |
An optical filtering device for selectively transmitting radiation from a scene having wavelengths within a selected wavelength interval comprising dispersing means arranged to provide spatial dispersion as a function of wavelength without substantial angular dispersion and modulating means arranged to selectively transmit radiation within at least one wavelength interval from at least one direction of radiation incident on the device. The device may also include means for forming an image of the scene. The device may comprise first and second spectrally dispersing elements, such as first and second diffraction gratings or first and second prisms, wherein the latter dispersing element counteracts the angular dispersion of the former. The device may also include a spatial light modulator, such as a ferroelectric liquid crystal spatial light modulator, for selectively transmitting radiation within a selected wavelength interval. This enables rapid switching between the selectively transmitted wavelength intervals. The device may therefore be used in a pattern recognition system, for forming a colour image of the scene to aid identification, or may be used for improved resolution colour photography or active imaging.
|
