Snapshot spectral imaging system

Spectral imaging is the combination of spectroscopy and imaging. These fields are well developed and are used intensively in many application fields including industry and the life sciences. The classical approach to acquire hyper-spectral data is to sequentially scan a sample in space or wavelength. These acquisition methods are time consuming because only two spatial dimensions, or one spatial and the spectral dimension, can be acquired simultaneously. With a computed tomography imaging spectrometer (CTIS) it is possible to acquire two spatial dimensions and a spectral dimension during a single integration time, without scanning either spatial or spectral dimensions. This makes it possible to acquire dynamic image scenes without spatial registration of the hyperspectral data. This is advantageous compared to tunable filter based systems which need sophisticated image registration techniques. While tunable filters provide full spatial and spectral resolution, for CTIS systems there is always a tradeoff between spatial and spectral resolution as the spatial and spectral information corresponding to an image cube is squeezed onto a 2D image. The presented CTIS system uses a spectral-dispersion element to project the spectral and spatial image information onto a 2D CCD camera array. The system presented in this paper is designed for a microscopy application for the analysis of fixed specimens in pathology and cytogenetics, cell imaging and material analysis. However, the CTIS approach is not limited to microscopy applications, thus it would be possible to implement it in a hand-held device for e.g. real-time, intra-surgery tissue classification.