An improved spectral reflectance estimation method was developed to transform captured RGB images to spectral reflectance. The novelty of our method is an iteratively reweighted regulated model that combines polynomial expansion signals. which was developed for spectral reflectance estimation. and a cross-polarized imaging system. https://www.roneverhart.com/ESP-LTD-SD-2-Sammy-Duet-Signature-Model-Electric-Guitar-Black-p20045/