Common descriptors of light quality fail to predict the chromatic diversity produced by the same illuminant in different contexts such as images of natural scenes. The aim of this paper was to introduce a new index, capable of predicting illuminantinduced variations in the chromatic diversity off natural scenes. The spectral reflectance of each pixel of 50 images of natural scenes obtained usin...

Perceptual colour difference in simple colour patches has been extensively studied in the history of colour science. However, these methods are not assumed to be applicable for predicting the perceived colour difference in complex colour patches such as digital images of complex scene. In this work existing metrics that predict the perceived colour difference in digital images of complex scene...

We propose a color management system for the color facsimile. It consists of protocols for the colorimetric calibration of the scanner and the printer by establishing the relationships between the device-dependent color coordinates and the device-independent CIELAB color space. The scanner calibration is based on 3rd order polynomial regression techniques. The printer calibration uses 3D triang...

Perceptual image distortion measures can play a fundamental role in evaluating and optimizing imaging systems and image processing algorithms. Many existing measures are formulated to represent “just noticeable differences” (JNDs), as measured in psychophysical experiments on human subjects. But some image distortions, such as those arising from small changes in the intensity of the ambient ill...

The main objective of this work was to test the performance of major formulas for assessment of small suprathreshold color differences in the blue region. The models examined include CIELAB color space based equations, including CIELAB, CIE94, CIEDE2000, CMC (l:c), BFD (l:c), and formulas based on more uniform color spaces, such as DIN99d, CAM02-SCD, CAM02-UCS, OSA-GP, and OSA-Eu in comparison ...

In this paper the effect of heat and ammonia treatment on the change in colour of oak wood (Quercus robur) and comparison of physical and mechanical properties were investigated. Wood specimens were made from heartwood and sapwood in dimensions 30×30×30 mm3. The specimens were subjected to heat treatment at 180oC and 230oC for 2 and 4 hours, others were treated by ammonia for 24 hours. After th...

We conducted a monitor-based subjective study on multilevel halftone. Observers in a halftone preference experiment selected stimuli in a paired comparison design. Images were halftoned using multilevel stochastic screening and multilevel error diffusion. Stimuli were presented on a calibrated monitor from distances equivalent to viewing 300 and 600 dpi prints. We applied Thurstone's law of com...

The design, production and characterization of tailored printable optical filters for visible optical communications are demonstrated. As result, the average color difference between the specified and the produced filters is 32.6, quantified in terms of CIELAB coordinates.