We present a novel spectral imaging technique that allows multiple gray-scale images to be combined in a single hardcopy print. The images are individually revealed when the print is illuminated by suitably chosen light sources. In its basic form, the technique utilizes the complementary relation between cyan, magenta, and yellow colorants and narrow band red, green, and blue illuminants to com...

Spectral printing aims to achieve an illuminant-invariant match between the original and the reproduction. Due to limited printer spectral gamuts, an errorless spectral reproduction is mostly impossible, and spectral gamut mapping is required to reduce perceptual errors. The recently proposed paramermismatch-based spectral gamut mapping (PMSGM) strategy minimizes such errors. However, due to it...

Chromatic adaptation transforms generally rely on a variant of the von Kries transformation method to account for changes in the LMS cone signals that occur when changing from one illuminant to another. Von Kries adaptation—also often referred to as the coefficient rule method or the diagonal transformation method—adjusts the 3 color channels by independent scale factors. Since there generally ...

A theory about how changes in the illuminant affect the color appearance of objects must specify how the visual system's adjustments to illuminant changes vary with the surface collection in a scene. I report an experiment designed to investigate this issue. The stimuli were CRT simulations of flat matte surfaces rendered under diffuse illumination. For all combinations of 7 daylight illuminant...

The processing pipeline of a digital camera converts the RAW image acquired by the sensor to a representation of the original scene that should be as faithful as possible. There are mainly two modules responsible for the color-rendering accuracy of a digital camera: the former is the illuminant estimation and correction module, and the latter is the color matrix transformation aimed to adapt th...

This paper considers the problem of shape-from-shading using nearby extended light sources. The paper reviews a number of methods that employ nearby illuminants, and describes a new technique that assumes a rectangular planar nearby distributed uniform isotropic illuminant. It is shown that such a light source illuminating a small Lambertian surface patch is equivalent to a single isotropic poi...

With the development of high-speed CMOS imagers, it is possible to acquire and process multiple images within the imager, prior to output. We refer to an imaging architecture that acquires a collection of images and produces a single result as multiple capture single image (MCSI). In this paper we describe some applications of the MCSI architecture using a monochrome sensor and modulating light...

The current paper proposes an illuminant estimation algorithm that estimates the spectral power distribution of an incident light source using its chromaticity determined based on the perceived illumination and highlight method. The proposed algorithm is composed of three steps. First, the illuminant chromaticity of the global incident light is estimated using a hybrid method that combines the ...

The dichromatic reflectance model introduced by Shafer [16] predicts that the colour signals of most materials fall on a plane spanned by a vector due to the material and a vector that represents the scene illuminant. Since the illuminant is in the span of all dichromatic planes, colour constancy can be achieved by finding the intersection of two or more planes. Unfortunately, this approach has...

In order to recover spectral reflectances or transmittances using a multispectral imaging based technique, it is necessary to know the spectral radiance of the illuminant used to light the samples in the acquisition process. In this study, we analyzed the influence of the spectral distribution of the illuminant on the reconstruction of spectral reflectances in the near infrared region of the sp...