The purpose of this research is to propose an effective color metric which can predict the perceptual image quality for Retinex method. In this paper, we first give a brief introduction of three kinds of typical single Retinex methods to improve the color reproduction. And then, we state the process for obtaining the observer rating value from the subjective evaluation experiment performed unde...

The lack of blue hue constancy has been identified as a significant shortcoming of the CIELAB color space. The CIECAM97s, CIELUV, IPT and MLab color spaces have been proposed as alternatives to CIELAB. Color gradients with fixed anchor values were used as stimuli in a visual experiment. This allowed an efficient comparison of the hue constancy of different color spaces. The results show that IP...

This study investigated the colorimetric properties of different veneering materials on core materials. Standardized specimens (10 mm × 10 mm × 1.5 mm) reflecting four core (polyetheretherketone (PEEK), zirconia (ZrO₂), cobalt-chromium-molybdenum alloy (CoCrMo), and titanium oxide (TiO₂); thickness: 1.5 mm) and veneering materials (VITA Mark II, IPS e.max CAD, LAVA Ultimate and VITA Enamic, all...

The Joint Photographic Experts Group's image compression algorithm has been shown to be a very efficient and powerful method of compressing images. However, there is litde substantive information about which color space should be utilized when implementing the JPEG algorithm. Currendy, the JPEG algorithm is set up for use with any three component color space. The objective of this research was ...

We examine mathematical properties of the CIEDE2000 color difference formula and illustrate that the CIEDE2000 color difference is not a continuous function of the CIELAB color pairs between which the difference is calculated. Particularly, we illustrate that ambiguities in the computation of mean hue angle and hue angle differences of color pairs contribute to a discontinuity in the formula fo...

Super resolution (SR) images play an important role in Image processing applications. Spatial resolution is the key parameter in many applications of image processing. Super resolution images can be used to improve the spatial resolution. In this paper a new SR image reconstruction algorithm is proposed using Integer wavelet transform (IWT) and Binary plane technique (BPT). The proposed method ...

We describe computational experiments to predict the perceived quality of multi-level halftone images. Our cornputations were based on a spatial color difference metric, S-CIELAB, that is an extension of CIELAB, a widely used industry standard. CIELAB predicts the discriminability of large uniform color patches. S-CIELAB includes a pre-processing stage that accounts for certain aspects of the s...

The evaluation of visual quality of color images has become very important and challenging task due to explosion of multimedia and graphics content on internet. An image exhibits loss in color information due to introduction of noise, blur, blocking artefacts, channel distortion and also during lossy compression. The primary goal of Image Quality Metric (IQM) is to measure emergence of such dis...

Simple color-difference formulae and pictorial images have traditionally been used to estimate the visual impact of color errors introduced by image-reproduction processes. But the limited gamut of RGB cameras constrains such analyses, particularly of natural scenes. The purpose of this work was to estimate visual sensitivity to color errors introduced deliberately into pictures synthesized fro...

Subjects examined image pairs consisting of an original and a reproduction created using either JPEG compression or digital halftoning. Subjects marked locations on the reproduction that differed detectably from the original. We refer to the distribution of error marks by the subjects as image distortion maps. The empirically obtained image distortion maps are compared to the visible difference...