Jon Y. Hardeberg

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In this article we describe the experimental setup of a multispectral image acquisition system consisting of a professional monochrome CCD camera and a tunable filter in which the spectral transmittance can be controlled electronically. We have performed a spectral characterisation of the acquisition system taking into account the acquisition noise. To(More)
We investigate methods for the recovery of reflectance spectra from the responses of trichromatic camera systems and the application of these methods to the problem of camera characterization. The recovery of reflectance from colorimetric data is an ill-posed problem, and a unique solution requires additional constraints. We introduce a novel method for(More)
We propose a method for the colorimetric characterization of a printer which can also be applied to any other type of digital image reproduction device. The method is based on a computational geometry approach. It uses a 3D triangulation technique to build a tetrahedral partition of the printer color gamut volume and it generates a surrounding structure(More)
We have carried out a psychophysical experiment to register perceived contrast. 17 observers viewed 15 images, each image was shown for 40 seconds where the observer stated the perceived contrast of the image. The results from the observers indicate that the consensus of contrast among experts decreases as the perceived contrast decreases. Experts also rate(More)
In this paper, we propose and discuss some approaches for measuring perceptual contrast in digital images. We start from previous algorithms by implementing different local measures of contrast and a parameterized way to recombine local contrast maps and color channels. We propose the idea of recombining the local contrast maps and the channels using(More)
This paper deals with the problem of spectral reflectance estimation from color camera outputs. Because the reconstruction of such functions is an inverse problem, stabilizing the reconstruction process is highly desirable. One way to do this is to decompose reflectance function on a basis functions like PCA. The present work proposes an algorithm making(More)