Recovering spectral data from digital prints with an RGB camera using multi-exposure method

摘要

The spectral data of a surface can be reconstructed from RGB camera response when reflectance spectrum of the surface and radiance spectrum of the light source are smooth enough. One factor that lowers the reconstruction performance of consumer level cameras is limited dynamic range. Details or intensity levels in low and high luminance regions can not be reliably detected from a single image. With multiple exposures it is possible to capture high dynamic range images. The aim of this study was to apply a multi-exposure method for spectral data reconstruction of prints and find how accuracy it is. Our intended application area is printed image digitization for image quality calculations. We measured the intensity levels and recovered spectral data of printed samples by taking two images using different exposure times. Based on the results multi-exposure method improves the accuracy of spectral data reconstruction of print samples compared to traditional methods and is the preferred choice for printed image digitization process.