Approaches to spectral imaging hardware.

Instruments used for spectral, multispectral, and hyperspectral imaging in the biosciences have evolved significantly over the last 15 years. However, very few are calibrated and have had their performance validated. Now that spectral imaging systems are appearing in clinics and pathology laboratories, there is a growing need for calibration and validation according to universal standards. In addition, some systems produce spectral artifacts that, at the very least, challenge data integrity if left unrecognized. This unit includes a comparison of the band-pass and light-transmission characteristics of electronic tunable filters, interferometers, and wavelength-dispersive spectral imaging instruments, as well as a description of how they work. Methods are described to test wavelength accuracy and perform radiometric calibration. A real-life example of spectral artifacts is dissected in detail in order to show how to detect, diagnose, verify, and work around their presence when they cannot be eliminated.