Multispectral imaging captures light across a limited number of spectral bands, typically ranging from 3 to 15, distributed across the spectrum. The choice of spectral bands varies depending on the specific application. The most straightforward method for multispectral imaging employs a filter wheel containing multiple bandpass filters. As the wheel rotates, different wavebands are sequentially positioned in front of the camera, enabling image acquisition for each band. While this method ensures the full spatial resolution of the camera is utilised, it requires time to capture the complete spectral data cube. For real-time, video-rate multispectral imaging, mosaic filter arrays—similar to the Bayer RGB pattern in colour cameras—are commonly used. “Filter-on-chip” multispectral cameras integrate narrow bandpass filters directly onto the 2D sensor array. Additionally, plenoptic cameras incorporate filter arrays within the optical path, positioned before the detector array.
While multispectral imagers generally capture a more limited spectral dataset, they offer a key advantage in measurement speed. A multispectral camera is typically considered a “real-time” spectral imager, making it ideal for capturing rapidly changing objects. Pro-Lite supplies a filter-wheel multispectral camera from XpectralTEK for art analysis. We also offer real-time multispectral cameras utilising mosaic filter technology from SILIOS, as well as plenoptic-based multispectral cameras from Surface Optics Corporation.
