This paper presents a color demosaicing method applied to the Bayer pattern color filter array (CFA). Reliable estimation of an edge direction, edge-directed asymmetric interpolation, and the use of color samples at immediate neighbors are considered as the key guidelines for smooth and sharp image restoration. Also, special interest is directed to local areas that are rich in high spatial frequency variations. For suppression of false colors likely to occur in those areas, a hue vector representation is introduced so that the spatial correlation between different color components may be exploited in consistent with the local constant-hue principle. Smoothing is repeated in the hue vector field a few times. Experimental results have shown preferable performances in terms of PSNR, CIELAB color difference, hue angle difference, CIE chromaticity and visual appearance, in particular resulting in less false colors.

Modeling visual attention provides an alternative methodology to image description in many applications such as adaptive content delivery and image retrieval. In this paper, we propose a robust approach to the modeling bottom-up visual attention. The main contributions are twofold: 1) We use a principal component analysis (PCA) to transform the RGB color space into three principal components, which intrinsically leads to an opponent representation of colors to ensure good saliency analysis. 2) A practicable framework for modeling visual attention is presented based on a region-level reliability analysis for each feature map. And then the salient map can be robustly generated for a variety of nature images. Experiments show that the proposed algorithm is effective and can characterize the human perception well.

We propose a noise suppression algorithm with the Kalman filter theory. The algorithm aims to achieve robust noise suppression for the additive white and colored disturbance from the canonical state space models with (i) a state equation composed of the speech signal and (ii) an observation equation composed of the speech signal and additive noise. The remarkable features of the proposed algorithm are (1) applied to adaptive white and colored noises where the additive colored noise uses babble noise, (2) realization of high performance noise suppression without sacrificing high quality of the speech signal despite simple noise suppression using only the Kalman filter algorithm, while many conventional methods based on the Kalman filter theory usually perform the noise suppression using the parameter estimation algorithm of AR (auto-regressive) system and the Kalman filter algorithm. We show the effectiveness of the proposed method, which utilizes the Kalman filter theory for the proposed canonical state space model with the colored driving source, using numerical results and subjective evaluation results.

Computational color constancy is a classical problem in computer vision. It is an under-constrained problem, which can be solved based on some constraint. Existing algorithms can be divided into two groups: physics-based algorithms and statistics-based approaches. In this paper, we propose a new hypothesis that the images generated under a same illumination have some similar features. Based on this hypothesis, a novel statistics-based color constancy algorithm is given and a new similarity function between images is also defined. The experimental results show that our algorithm is effective and it is more important that the dimension of the features in our algorithm is much lower than many former statistics-based algorithms.

In this paper, we present a clean and simple formulation of survey propagation (SP) for constraint-satisfaction problems as "probabilistic token passing". The result shows the importance of extending variable alphabets to their power sets in designing SP algorithms.

This paper addresses the issue of transmission scheduling in wireless ad hoc networks. We propose a Time Division Multiple Access (TDMA) scheduling scheme based on edge coloring and probabilistic assignment, called CP-TDMA. We categorize the conflicts suffered by wireless links into two types: explicit conflicts and implicit conflicts, and utilize two different strategies to deal with them. Explicit conflicts are avoided completely by a simple distributed edge-coloring algorithm µ-M, and implicit conflicts are minimized by applying probabilistic time slot assignments to links. We evaluate CP-TDMA analytically and numerically, and find that CP-TDMA, which requires only local information exhibits a better performance than previous work.

The reduction of a structural pattern at specific gray levels or at the special condition of image data has mainly been discussed in digital halftone methods. This problem is more severe in some flat panel displays because their black levels typically are brighter than other displays blocks. The authors proposed an advanced confined error diffusion (ACED) algorithm which was a well-organized halftone algorithm for flat panel devices. In this paper, we extend the ACED algorithm to the multi-level systems, which are capable of displaying more than 2 levels. Our extension has two merits for the hardware implementation. First, it can be processed in real time using the look-up table based method. The second one is the flexibility of selecting the used gray level. This paper discusses the performance of the proposed algorithms with experimental results for natural test images.

A method for measuring the luminance distribution of an electron beam spot was described, which is fundamental to evaluate the resolution of a color display tube. First, to achieve high sensitivity and wide dynamic range identical to those of visual inspection, we proposed the use of an ICCD camera for imaging and two levels of sensitivity. With that method, we were able to measure the luminance distribution of an electron beam spot over a range of currents that extends from the extremely weak cathode current region to large current that correspond to the peak luminance. Specifically, we were able to measure the entire distribution shape from the base to the peak for beam spots in the cathode current range from 20 µA to 300 µA, while compensating the absolute luminance level. Second, a reconstruction algorithm of entire beam distribution from the shape of the masked part of the beam was also proposed, in which shift error is compensated to reduce the variance in measurement results caused by jitter noise in the conventional image processing method. That algorithm improves the reproducibility of repeated measurements. Specifically, a function for estimating the actual shift from the first-order moment of the image was incorporated into the spot shape reconstruction algorithm, resulting in a reduction of the standard deviation for repeated measurements of the horizontal beam spot diameter at 5% intensity from 0.02 mm to 0.005 mm.

We demonstrate a novel display structure for color electronic paper for the first time. Fully transparent amorphous oxide TFT array is directly deposited onto color filter array and combined with E Ink Imaging Film. Taking advantage of the transparent property of the oxide TFT, the color filter and TFT array are positioned at the viewing side of the display. This novel "Front Drive" display structure facilitates the alignment of the color filter and TFT dramatically.

We investigated the effect of viewing conditions on human visual perception of colorfulness and constructed a mathematical model for colorfulness by fitting regression curves to LUTCHI color appearance data. This model enables the simple and effective prediction of the relative appearance attribute of colorfulness as a function of brightness and saturation, taking into account a range of viewing conditions, and hence provides a method of image reproduction for home display systems that can be easily adapted according to indoor viewing conditions.

The power reduction of display devices has become an important issue for extending battery life and running time when they are used in digital multimedia broadcasting (DMB) mobile phones. DMB mobile phones generally use 16-bit data per pixel to reduce power consumption even though a liquid crystal display (LCD) graphic controller can support 16-, 18-, and 24-bit data per pixel. Also, the total transmission time of 16-bit data per pixel is only half that for 18- and 24-bit data per pixel. Decoded 24-bit image data in the frame memory of a DMB decoder are asymmetrically truncated to 16-bit image data. This results in a lack of smoothness such as blocking effects and/or pseudo edge artifacts. To solve these problems, the author proposes and implements a new asymmetric pixel data truncation error compensation algorithm using 1-bit least significant bit (LSB) data expansion with correlated color information for the purpose of ensuring smoothness. In the experimental results, the proposed algorithm is able to correct various artifacts.

Skin tone detection in conditions where illuminate intensity and/or chromaticity can vary often comes with high computational time or low accuracy. Here a technique is presented integrating chromaticity and intensity normalization combined with a neural skin tone classification network to achieve robust classification faster than other approaches.

Grey world algorithm is a well-known color constancy algorithm. It is based on the Grey-World assumption i.e., the average reflectance of surfaces in the world is achromatic. This algorithm is simple and has low computational costs. However, for the images with several colors, the light source color could not be estimated correctly using the Grey World algorithm. In this paper, we propose a Multi-scale Adaptive Grey World algorithm (MAGW). First, multi-scale images are obtained based on wavelet transformation and the illumination color is estimated from different scales images. Then according to the estimated illumination color, the original image is mapped into the image under a canonical illumination with supervision of an adaptive reliability function, which is based on the image entropy. The experimental results show that our algorithm is effective and also has low computational costs.

To keep in step with the rapid progress of high quality imaging systems, the Digital Cinema Initiative (DCI) has been issuing digital cinema standards that cover all processes from production to distribution and display. Various evaluation measurements are used in the assessment of image quality, and, of these, the required number of quantization bits is one of the most important factors in realizing the very high quality images needed for cinema. While DCI defined 12 bits for the bit depth by applying Barten's model to just the luminance signal, actual cinema applications use color signals, so we can say that this value has an insufficient theoretical basis. This paper, first of all, investigates the required number of quantization bits by computer simulations in discrete 3-D space for the color images defined using CIE's XYZ signal. Next, the required number of quantization bits is formulated by applying Taylor's development in the continuous value region. As a result, we show that 13.04 bits, 11.38 bits, and 10.16 bits are necessary for intensity, density, and gamma-corrected signal quantization, respectively, for digital cinema applications. As these results coincide with those from calculations in the discrete value region, the proposed analysis method enables a drastic reduction in the computer simulation time needed for obtaining the required number of quantization bits for color signals.

A total coloring of a graph G is a coloring of all elements of G, i.e. vertices and edges, such that no two adjacent or incident elements receive the same color. Let L(x) be a set of colors assigned to each element x of G. Then a list total coloring of G is a total coloring such that each element x receives a color contained in L(x). The list total coloring problem asks whether G has a list total coloring for given L. In this paper, we give a sufficient condition for a series-parallel graph to have a list total coloring, and we present a linear-time algorithm to find a list total coloring of a given series-parallel graph G if G and L satisfy the sufficient condition.

This letter presents a simple scheme to transform colors to some representative classes for color information reduction. Then, the weighted distributions of color index histogram (CIH) and local binary pattern (LBP) are applied to measure the similarity of adjacent texture regions during the segmentation process. In addition, for improving the segmentation accuracy, an efficient boundary checking algorithm is proposed. The proposed method not only saves execution time but also segments the distinct texture regions correctly.

Fitts' law has been applied in many studies to evaluate pointing tasks. However, the quantitative effect of using color in the interfaces has not been discussed in the literature. This paper introduces research on the effects of color in pointing tasks using Fitts' law as the evaluation method. Different colors and color presentation styles are applied in the experiments which are similar in design to the paradigmatic Fitts' law pointing task. The experimental results show that when the subjects use a mouse as the input device, there is no significant difference between an interface with a colored target and one with a white target in the mean performance time. The results also reveal that color presentation styles will offer no significant difference to pointing tasks when the mouse is applied. However, when the interface of tablet PC and pen was applied, subjects without much experience in tablet personal computer usage needed more time to perform the task with colored targets than with a white target. Furthermore, when the colors are changed randomly during the selection process, the difference is even more obvious. These results are confirmed by a Checking Experiment and a Learning Effect Experiment which we performed on different groups of subjects.

In this paper we propose a novel method to inpaint highlights and to remove the specularity in the image with specular objects by the color line projection. Color line projection is the method that a color with a surface reflection component is projected near the diffuse color line by following the direction of the specular color line. We use two captured images using different exposure time so that the clue of the original color in a highlight area is searched from two images since the color at the highlight region is distorted and saturated to the illumination color. In the first step of the proposed procedure, the region corresponding to the highlight is generated and the clue of the original highlight color is acquired. In the next step, the color line is generated by the restricted region growing method around the highlight region, and the color line is divided into the diffuse color line and the specular color line. In the final step, pixels near the specular color line are projected onto near the diffuse color line by the color line projection, in which the modified random function is applied to realistically inpaint the highlight. One of advantages in our method is to find the highlight region and the clue of the original color of the highlight with ease. It also efficiently estimates the surface reflection component which is utilized to remove specularity and to inpaint the highlight. The proposed method performs the highlight inpainting and the specular removal simultaneously once the color line is generated. In addition, color line projection with the modified random function can make the result more realistic. We show experimental results from the real images and make a synthesis of the real image and the image modified by the proposed method.

A color filter is the penetrable device adhering red, green, and blue organic color resists onto the surface of glass substrate for application of liquid crystal displays. It is fabricated by several technologies, including lithographic processes of coating, baking, exposing, etching, and rinsing. Inkjet printing technology has potentially implemented on the fabrication of the large-size panel with organic molecular film since this technology offers an efficient and steady production procedure. To achieve the basic specifications and requirements of high color performance, high color purity, high flatten, low reflective, and low production cost, inkjet printing technology will be seriously considered in the color filter manufacturing. Here we present the experimental results on physical and chromatic characteristics of color filters by implementing inkjet printing technology. To verify the chromatic characteristics of the resultant color filters, CIE 1931 chromaticity diagram is adopted to present the coordination of color distribution. For the green color ink, the results are x=0.30950.04, y=0.59120.04, brightness of Y=58.887 for 50 droplets and x=0.31030.04, y=0.57840.04, brightness of Y=60.328 for 41 droplets. For the blue color ink, the result is x=0.14900.04, y=0.10150.04, brightness of Y=8.808. For the red color ink, the result is x=0.5720.04, y=0.3200.04, brightness of Y=27.1.

It has been shown that the maskless dye-diffusion technique is applicable to a conjugated polymer poly(9,9-dioctylfluorene). The introduction of Coumarin 6 and Nile red results in green and white emission, with the increased onset voltage for the both cases. It has also been confirmed that the heat treatment effect during the maskless dye diffusion technique results in not the increase but the decrease of the onset voltage, indicating that the dye plays a role of carrier trap in the polymer.