This paper aims to evaluate the visual quality of the dynamic relighting of manufactured surfaces from Reflectance Transformation Imaging acquisitions. The first part of the study aimed to define the optimum parameters of acquisition using the RTI system: Exposure time, Gain, Sampling density. The second part is the psychometric experiment using the Design of Experiments approach. The results of this study help us to determine the influence of the parameters associated with the acquisition of Reflectance Transformation Imaging data, the models associated with relighting, and the dynamic perception of the resulting videos
Inspired by the concept of the colour filter array (CFA), the research community has shown much interest in
adapting the idea of CFA to the multispectral domain, producing multispectral filter arrays (MSFAs). In addition
to newly devised methods of MSFA demosaicking, there exists a wide spectrum of methods developed for CFA.
Among others, some vector based operations can be adapted naturally for multispectral purposes. In this paper,
we focused on studying two vector based median filtering methods in the context of MSFA demosaicking. One
solves demosaicking problems by means of vector median filters, and the other applies median filtering to the
demosaicked image in spherical space as a subsequent refinement process to reduce artefacts introduced by
demosaicking. To evaluate the performance of these measures, a tool kit was constructed with the capability
of mosaicking, demosaicking and quality assessment. The experimental results demonstrated that the vector
median filtering performed less well for natural images except black and white images, however the refinement
step reduced the reproduction error numerically in most cases. This proved the feasibility of extending CFA
demosaicking into MSFA domain.
KEYWORDS: RGB color model, 3D modeling, LCDs, Instrument modeling, Optimization (mathematics), Data modeling, Digital Light Processing, CRTs, Projection devices, Projection systems
We have defined an inverse model for colorimetric characterization of additive displays. It is based on an
optimized three-dimensional tetrahedral structure. In order to minimize the number of measurements, the
structure is defined using a forward characterization model. Defining a regular grid in the device-dependent
destination color space leads to heterogeneous interpolation errors in the device-independent source color space.
The parameters of the function used to define the grid are optimized using a globalized Nelder-Mead simplex
downhill algorithm. Several cost functions are tested on several devices. We have performed experiments with
a forward model which assumes variation in chromaticities (PLVC), based on one-dimensional interpolations for
each primary ramp along X, Y and Z (3×3×1-D). Results on 4 devices (2 LCD and a DLP projection devices,
one LCD monitor) are shown and discussed.
The purpose of this paper is to propose a color image watermarking scheme based on an image dependent color gamut
sampling of the L*a*b* color space. The main motivation of this work is to control the reproduction of color images on
different output devices in order to have the same color feeling, coupling intrinsic informations on the image gamut and
output device calibration. This paper is focused firstly on the research of an optimal LUT (Look Up Table) which both
circumscribes the color gamut of the studied image and samples the color distribution of this image. This LUT is next
embedded in the image as a secret message. The principle of the watermarking scheme is to modify the pixel value of the
host image without causing any change neither in image appearance nor on the shape of the image gamut.
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