These teachings relate to compact snapshot multispectral imaging systems.
A multispectral or hyperspectral imaging system (the terms multispectral and hyperspectral are used interchangeably here) is commonly used to observe objects or scenes, whereby light emitted or reflected by a given object or scene is imaged by some means onto a detecting element or array of detecting elements, where multiple images with different spectral content can readily be observed or recorded.
Due to the short temporal duration of many events, it is necessary to capture multispectral data in a short amount of time. A snapshot multispectral imaging system is a multispectral imaging system that captures all desired spectral images at a single moment, rather than relying on either spatial or spectral scanning of the object or scene.
In many designs incorporating snapshot multispectral imaging systems, there is a need for the overall system to be compact. Such needs stem from weight and space constraints in the application in which the system is used. Conventional snapshot multispectral imaging systems are typically large in size due to their large single aperture optics or optical relay subsystems.
Recent advances in snapshot multispectral or hyperspectral imaging systems have been made using Computed Tomography Imaging Spectrometer (CTIS) devices. In these devices, the image is dispersed across multiple dispersive orders using a computer generated hologram and onto a single detector or detector array, analogous to integrated slices through the 3D data cube at various angles across the two spatial dimensions. Using reconstructive techniques similar to those used in CT scans in the medical field, they used computed tomography to build up the 3D data cube from the two dimensional detector. In this manner, spatial and spectral information is captured in a single integration time. Unfortunately, this technique has limitations on the spatial and spectral resolutions that can be captured due to the limited number of dispersive orders that can be generated. Furthermore, these systems tend to be fairly large.
There is therefore a need for a snapshot multispectral imaging system that is more compact in physical size than current multispectral imaging systems.
Furthermore, there is also a need for a snapshot multispectral imaging system that has greater spatial and spectral resolution than current imaging systems.
Furthermore, there is also a need for a snapshot multispectral imaging system that has a greater degree of image co-registration than current imaging systems.
Still further, there is a need for an imaging system that provides a combination of the characteristics described above with superior trade-offs than have been previously attainable.