This paper addresses the problem of lip segmentation in color space, which is a crucial issue to the success of a lip-reading system. We present a new segmentation approach to lip contour extraction by taking account of the color difference between lip and skin in color space. Firstly, we obtain a lip segment sample via a color transformation sequence in 1976 CIELAB and LUX color spaces. Second...

This paper addresses the problem of lip segmentation in color space that is a crucial issue to a successful lip-reading system. We present a new segmentation approach to lip contour extraction by taking account of the maximum a posterior Markov random field (MAPMRF) framework. We first examine various color models and select a simple color transform derived from LUX and 1976 CIELAB color space ...

Estimates were made of the efficiency with which color spaces code color information from images of natural scenes. Six spaces were tested, namely, CIE XYZ tristimulus space, and the spaces CIELUV, CIELAB, CIELAB and S-CIELAB after chromatic adaptation with CMCCAT2000, and the space CIECAM02. For each space, the information available and the information retrieved in color matching were calculat...

The OSA Uniform Color Scales were derived using a unique geometry for the physical samples. Regular rhombohedral packing allows each sample to be compared to twelve other equally distant samples. While this sampling scheme provides an efficient geometry for sample comparison and allows multiple cleavage planes, it obscures the underlying perceptual attributes. However, it is relatively straight...

In the world of digital image and video processing, encoding and/or compression errors are often assessed in terms of the signal dimensions (e.g., RGB or YCBCR) using quantities such as RMS deviation or signal-to-noise ratio with little or no regard for the radiometric linearity of the quantities or the ultimate appearance to observers. When visual models are utilized it is usually with the aim...

A scanner characterization method based on an analytic spectral model was derived. Themethod firstmodeled the spectral formation of eachmedium using either Beer-Bouguer Law or Kubelka-Munk theory. Scanner digital counts were then empirically related to dye concentrations. From these estimated dye concentrations, either spectral transmittance or spectral reflectance factor could be predicted. Th...

Color transformations are frequently embodied in look-up tables (LUTs) whose content is the result of computation performed on the basis of color measurements. Noise in color measurements and device output gives LUTs that result in lack of smoothness in color transitions. Smoothing of color LUTs is therefore typically performed, often with a significant loss of accuracy. This paper proposes a m...

This paper addresses the problem of interpolating missing color components at the output of a Bayer color filter array (CFA), a process known as demosaicking. A luma-chroma demultiplexing algorithm is presented in detail, using a least-squares design methodology for the required bandpass filters. A systematic study of objective demosaicking performance and system complexity is carried out, and ...

This paper shows a computational technique of how to construct a nearly isometric transformation from a color space with a non-Euclidean color difference formula into an Euclidean space. The resulting transformation is a combination of a one-dimensional color lookup table (CLUT) to transform lightness values and a two-dimensional CLUT to transform chroma and hue coordinates. As an example the C...

To achieve high image quality throughout a digital imaging system, the first requirement is to ensure the quality of the device that captures real-world physical images to digital images, for example a desktop scanner. Several factors have influence on this quality: optical resolution, bit depth, spectral sensitivities, and acquisition noise, to mention a few. In this study we focus on the colo...