  Colour differences between healthy and diseased tissue in the
gastrointestinal tract are detected visually by clinicians during white light
endoscopy (WLE); however, the earliest signs of disease are often just a
slightly different shade of pink compared to healthy tissue. Here, we propose
to target alternative colours for imaging to improve contrast using custom
multispectral filter arrays (MSFAs) that could be deployed in an endoscopic
chip-on-tip configuration. Using an open-source toolbox, Opti-MSFA, we examined
the optimal design of MSFAs for early cancer detection in the gastrointestinal
tract. The toolbox was first extended to use additional classification models
(k-Nearest Neighbour, Support Vector Machine, and Spectral Angle Mapper). Using
input spectral data from published clinical trials examining the oesophagus and
colon, we optimised the design of MSFAs with 3 to 9 different bands. We
examined the variation of the spectral and spatial classification accuracy as a
function of number of bands. The MSFA designs have high classification
accuracies, suggesting that future implementation in endoscopy hardware could
potentially enable improved early detection of disease in the gastrointestinal
tract during routine screening and surveillance. Optimal MSFA configurations
can achieve similar classification accuracies as the full spectral data in an
implementation that could be realised in far simpler hardware. The reduced
number of spectral bands could enable future deployment of multispectral
imaging in an endoscopic chip-on-tip configuration.
