1. An illumination device for use with a product inspection machine, said illumination device configured for product to pass through said illumination device along a product trajectory, comprising: at least one horizontally-disposed product illumination assembly having a first horizontally disposed array of semiconductor light sources in a repeated wavelength-emission sequence of at least two wavelengths, and a second horizontally disposed array of semiconductor light sources having a repeated wavelength-emission sequence of at least two wavelengths, said at least one horizontally-disposed product illumination assembly having a viewport therethrough, said at least one horizontally-disposed product illumination assembly positioned on one side of said product trajectory, said semiconductor light sources of said two horizontally disposed arrays configured to pulsedly illuminate a scanline, at least one horizontally-disposed background assembly having a background surface aligned with said viewport and said scanline, said at least one horizontally-disposed background assembly having at least one horizontally disposed background array of semiconductor light sources identical in wavelength emission to the combination of said first array of semiconductor light sources and said second array of semiconductor light sources, said at least one horizontally disposed background array of semiconductor light sources configured to pulsedly illuminate said background surface, said at least one horizontally-disposed background assembly positioned opposite said product trajectory from said at least one horizontally-disposed product illumination assembly.