Color Ones Research Articles

Triple color images encryption algorithm based on scrambling and the reality-preserving fractional discrete cosine transform

An image encryption algorithm to secure three color images simultaneously by combining scrambling with the reality-preserving fractional discrete cosine transform (RPFrDCT) is proposed. The three color images to be encrypted are converted to their indexed formats by extracting their color maps, which can be considered as the three components of a color image. These three components are affected each other by scrambling the interims obtained from vertically and horizontally combining the three indexed formats with the help of the chaos-based cyclic shift. The three scrambled components are separately transformed with the RPFrDCT, in which the generating sequences are determined by the Chirikov standard chaotic map. Arnold transform is used to further enhance the security. Due to the inherent properties of the chaotic maps, the cipher keys are highly sensitive. Additionally, the cipher image is a single color image instead of three color ones, and is convenient for display, storage and transmission due to the reality property of RPFrDCT. Numerical simulations are performed to show the validity of the proposed algorithm.

Colorization for Gray Scale Facial Image by Locality-Constrained Linear Coding

Colorization for gray scale facial image is an important technique in various practical applications. However, the methods that have been proposed are essentially semi-automatic. In this paper, we present a new probabilistic framework based on Maximum A Posteriori (MAP) estimation to automatically transform the given gray scale facial image to corresponding color one. Firstly, the input image is divided into several patches and non-parametric Markov random field (MRF) is employed to formulate the global energy. Secondly, Locality-constrained Linear Coding (LLC) is employed to learn the color distribution for each patch. At the same time, the simulated annealing algorithm is employed to iteratively update the patches chosen by LLC to optimize the MRF by decreasing global energy cost. The experimental results demonstrate that the proposed framework is effective to colorize the gray scale facial images to corresponding color ones.

Color model and method for video fire flame and smoke detection using Fisher linear discriminant

Video fire detection is playing an increasingly important role in our life. But recent research is often based on a traditional RGB color model used to analyze the flame, which may be not the optimal color space for fire recognition. It is worse when we research smoke simply using gray images instead of color ones. We clarify the importance of color information for fire detection. We present a fire discriminant color (FDC) model for flame or smoke recognition based on color images. The FDC models aim to unify fire color image representation and fire recognition task into one framework. With the definition of between-class scatter matrices and within-class scatter matrices of Fisher linear discriminant, the proposed models seek to obtain one color-space-transform matrix and a discriminate projection basis vector by maximizing the ratio of these two scatter matrices. First, an iterative basic algorithm is designed to get one-component color space transformed from RGB. Then, a general algorithm is extended to generate three-component color space for further improvement. Moreover, we propose a method for video fire detection based on the models using the kNN classifier. To evaluate the recognition performance, we create a database including flame, smoke, and nonfire images for training and testing. The test experiments show that the proposed model achieves a flame verification rate receiver operating characteristic (ROC I) of 97.5% at a false alarm rate (FAR) of 1.06% and a smoke verification rate (ROC II) of 91.5% at a FAR of 1.2%, and lots of fire video experiments demonstrate that our method reaches a high accuracy for fire recognition.

インテリアの印象に及ぼす光色と物体色の影響

An experiment in which subjects rated their impression of 50 interior environments which were the contrasting combinations of two lighting colors, five wall and floor color combinations, and five furniture colors were performed. Of particular significance was the higher harmony ratings assigned to color layouts presenting blue and green furniture colors when they are with similar wall and floor color hues than others. The ratings of harmony rose when room model presented bluish walls and floors and was illuminated by daylight fluorescent lamps rather than bulb color ones. However, the rating differences between the two lamps were not clear when assessing likability or comfort.

A new Method for Color Image Quality Assessment

Humans have always seen the world in color. In the last three decades, there has been rapid and enormous transition from grayscale images to color ones. Well-known objective evaluation algorithms for measuring image quality include mean squared error (MSE), peak signal-to-noise ratio (PSNR), and human Visual System based one are structural similarity measures and edge based similarity measures. One of the common and major limitations of these objective measures is that they evaluate the quality of grayscale images only and don’t make use of image color information. Since, Color is a powerful descriptor that often simplifies the object identification and extraction from a scene so color information also could influence human beings’ judgments. So, in this paper new objective color image quality measure in spatial domain is proposed that overcomes the limitation of these existing methods significantly, is easy to calculate and applicable to various image processing applications. The proposed quality measure has been designed as a combination of four main factors: luminance similarity, structure correlation, edge similarity, and color similarity. This proposed index is mathematically defined and in it HVS model is explicitly employed. Experiments on various image distortion types indicate that this index performs significantly better than other traditional error summation methods and existing similarity measures.

Unified Direct Visual Tracking of Rigid and Deformable Surfaces Under Generic Illumination Changes in Grayscale and Color Images

The fundamental task of visual tracking is considered in this work as an incremental direct image registration problem. Direct methods refer to those that exploit the pixel intensities without resorting to image features. We propose new transformation models and optimization methods for directly and robustly registering images (including color ones) of rigid and deformable objects, all in a unified manner. We also show that widely adopted models are in fact particular cases of the proposed ones. Indeed, the proposed general models combine various classes of image warps and ensure robustness to generic lighting changes. Finally, the proposed optimization method together with the exploitation of all possible image information allow the algorithm to achieve high levels of accuracy. Extensive experiments are reported to demonstrate that visual tracking can indeed be highly accurate and robust despite deforming objects and severe illumination changes.

Generic Lossless Visible Watermarking—A New Approach

A novel method for generic visible watermarking with a capability of lossless image recovery is proposed. The method is based on the use of deterministic one-to-one compound mappings of image pixel values for overlaying a variety of visible watermarks of arbitrary sizes on cover images. The compound mappings are proved to be reversible, which allows for lossless recovery of original images from watermarked images. The mappings may be adjusted to yield pixel values close to those of desired visible watermarks. Different types of visible watermarks, including opaque monochrome and translucent full color ones, are embedded as applications of the proposed generic approach. A two-fold monotonically increasing compound mapping is created and proved to yield more distinctive visible watermarks in the watermarked image. Security protection measures by parameter and mapping randomizations have also been proposed to deter attackers from illicit image recoveries. Experimental results demonstrating the effectiveness of the proposed approach are also included.

Kairomone Attractant for the Leafmining Fly, Liriomyza bryoniae (Diptera, Agromyzidae)

A field test carried out in an industrial greenhouse in Lithuania revealed the attractiveness of synthetic methyl salicylate (MeSa) towards an economically important leafmining tomato pest, Liriomyza bryoniae (Kaltenbach) (Diptera, Agromyzidae). The behavioural reaction of the flies depended very much on the simultaneous presence of both olfactory and visual stimuli. The attractiveness depended on the colour of a sticky trap: MeSa attracted significantly more flies (ca. 2.2 times) when placed in yellow traps than in aluminium foil colour ones, when catches in such traps were compared to a corresponding control. L. bryoniae is the first species within the Agromyzidae family attracted by MeSa. The attractant was attributed to kairomones, as the compound is known as a plant-produced volatile. MeSa can be an effective extra-tool for increasing the attractiveness of traps. It should be evaluated in future whether such trap/bait combination is effective for the mass trapping of L. bryoniae leafminers in greenhouses (closed area).

Color image processing [basics and special issue overview

Humans have always seen the world in color but only recently have we been able to generate vast quantities of color images with such ease. In the last three decades, we have seen a rapid and enormous transition from grayscale images to color ones. Today, we are exposed to color images on a daily basis in print, photographs, television, computer displays, and cinema movies, where color now plays a vital role in the advertising and dissemination of information throughout the world. Color monitors, printers, and copiers now dominate the office and home environments, with color becoming increasingly cheaper and easier to generate and reproduce. Color demands have soared in the marketplace and are projected to do so for years to come. With this rapid progression, color and multispectral properties of images are becoming increasingly crucial to the field of image processing, often extending and/or replacing previously known grayscale techniques. We have seen the birth of color algorithms that range from direct extensions of grayscale ones, where images are treated as three monochrome separations, to more sophisticated approaches that exploit the correlations among the color bands, yielding more accurate results. Hence, it is becoming increasingly necessary for the signal processing community to understand the fundamental differences between color and grayscale imaging. There are more than a few extensions of concepts and perceptions that must be understood in order to produce successful research and products in the color world.

Preservative characteristics of photographic films and papers on the speed method

As archives, photograph is the evident records of historical facts and experiences. Thus, it is worth preserving. Unlike other documents silver halide photographic films and prints are quite sensitive to environmental factors such as light, temperature and humidity, which demands careful treatment in preservation. This study was carried out to select popular photographic films and papers on the market, to examine their photographic speeds (or sensitivities) and to compare and analyze their preservative features after keeping them some time in a weather-o-meter. Consequently, B/W materials were superior to color ones in preservation. And films were better than papers in the same manner. But we were not able to observe remarkable differences among material's manufacturers.

Adaptive skin-color filter

In this paper, we propose a new method, called an adaptive skin color filter, for detecting skin color regions in a color image. The use of skin color provides an efficient way to find candidate regions for faces or hands in color images. However, it is not easy to find skin color regions because the color of skin regions varies from image to image due to a variety of reasons. Since most of the previous methods adopt a fixed threshold scheme, they are useful only in the restricted (i.e., controlled) environment. However, our method is applicable to images in more general situations since it is capable of adaptively adjusting its threshold values and effectively separating skin color regions from similar background color regions. Our method consists of basically two stages. In the first stage, a thresholding box in HSV color space is updated adaptively using a color histogram under the assumption that the area of skin color regions is comparable to that of similar background color ones. In the second stage, color vectors inside the thresholding box are classified into two groups: skin color vectors and background color vectors. Our method and other conventional methods were tested with 379 images obtained from the Internet. Experimental results show that our method is robust to the variations of skin regions’ color compared to the conventional methods.

Optical properties of magnetic crystals

From symmetry considerations and using generalized Onsager relations, it is shown that 66 of the 90 magnetic classes, consisting of 29 single colour and 37 double colour ones, can exhibit what may be called the strain gyrotropic rotation. Similarly, 69 of the 90 magnetic classes, consisting of 21 single colour and 48 double colour ones, can exhibit what may be called the strain gyrotropic birefringence. A crystal in the class m3 or m3m is interesting as it can exhibit strain gyrotropic rotation despite its being cubic and incapable of exhibiting gyrotropic rotation in the unstressed state. Similarly, a crystal in the classm3m, is interesting as it can exhibit strain gyrotropic birefringence despite its being cubic and incapable of exhibiting gyrotropic birefringence in the unstressed state.

Birefringence and optical activity in magnetic crystals

From symmetry considerations and using genera-lized Onsager relations, it is shown that all the 31 pyromagnetic crystal classes, consisting of 13 single and 18 double colour ones, can exhibit a Faraday type optical rotation called the gyrotropic rotation. Similarly, 66 of the 90 magnetic classes, consisting of 20 single and 46 double colour ones, can exhibit what may be called the gyrotrop i c birefringence. A crystal in the class 43m or m 3m is interesting as it can exhibit birefringence of this special type despite its being cubic.