Snapshot advantage: a review of the light collection improvement for parallel high-dimensional measurement systems

Abstract

Imaging spectrometers collect data over three dimensions—two spatial $(x,y)$ and one spectral $(\lambda )$—so that the complete $(x,y,\lambda )$ dataset is typically referred to as a datacube. The most common method for categorizing the various types of imaging spectrometers is by the portion of the datacube collected in a single detector readout. “Whiskbroom” spectrometers, which use a linear array of detectors, collect a single column of the datacube at a time and thus scan across the two spatial dimensions of the datacube (see Fig. 1).¹ “Pushbroom” spectrometers use a 2D detector array, and thus collect a vertical slice of the datacube at once so that only one spatial dimension needs to be scanned to fill out the cube.² A filtered camera, constructed by placing a filter wheel or tunable spectral filter in front of a camera, collects a horizontal slice and thus needs to scan along the spectral dimension to complete the data set.³ Other scanning modalities exist, such as Fourier Transform imaging spectrometry (FTIS), but these can be shown^4,5 as equivalent to one of the above categories—in this case, the filtered camera.