Colorimetric tolerances of digital images

An environment to derive colorimetric tolerances of images was established and an experiment using this new environment was performed. This environment allows for images to be digitally captured, colorimetrically manipulated, displayed, observed, and statistically evaluated. The visual experiment measured perceptibility and acceptability colorimetric tolerances for images using paired comparison techniques. Thirty-two observers judged six typical photographic scenes displayed on a high resolution color monitor. These scenes were manipulated using ten linear and nonlinear functions in the CIELAB dimensions of lightness, chroma, and hue angle. The tolerances were determined using probit analysis. It was found that scene content did not significantly affect the tolerances. The CIELAB, CMC, and MCSL color difference equations were shown to be inadequate for accurately modeling image tolerances. Finally, possible applications of this work are described

Print-Scan Resilient Text Image Watermarking Based on Stroke Direction Modulation for Chinese Document Authentication

Print-scan resilient watermarking has emerged as an attractive way for document security. This paper proposes an stroke direction modulation technique for watermarking in Chinese text images. The watermark produced by the idea offers robustness to print-photocopy-scan, yet provides relatively high embedding capacity without losing the transparency. During the embedding phase, the angle of rotatable strokes are quantized to embed the bits. This requires several stages of preprocessing, including stroke generation, junction searching, rotatable stroke decision and character partition. Moreover, shuffling is applied to equalize the uneven embedding capacity. For the data detection, denoising and deskewing mechanisms are used to compensate for the distortions induced by hardcopy. Experimental results show that our technique attains high detection accuracy against distortions resulting from print-scan operations, good quality photocopies and benign attacks in accord with the future goal of soft authentication

Affective iconic words benefit from additional sound–meaning integration in the left amygdala

Recent studies have shown that a similarity between sound and meaning of a word (i.e., iconicity) can help more readily access the meaning of that word, but the neural mechanisms underlying this beneficial role of iconicity in semantic processing remain largely unknown. In an fMRI study, we focused on the affective domain and examined whether affective iconic words (e.g., high arousal in both sound and meaning) activate additional brain regions that integrate emotional information from different domains (i.e., sound and meaning). In line with our hypothesis, affective iconic words, compared to their non‐iconic counterparts, elicited additional BOLD responses in the left amygdala known for its role in multimodal representation of emotions. Functional connectivity analyses revealed that the observed amygdalar activity was modulated by an interaction of iconic condition and activations in two hubs representative for processing sound (left superior temporal gyrus) and meaning (left inferior frontal gyrus) of words. These results provide a neural explanation for the facilitative role of iconicity in language processing and indicate that language users are sensitive to the interaction between sound and meaning aspect of words, suggesting the existence of iconicity as a general property of human language

Simulation and analysis of a digital scanning system

The analysis and simulation of the motion of a digitally-controlled digital imaging system is presented. The dynamic system consists of a scanning carriage, power transmission elements, a prime mover, and a control subsystem. The prime mover is a permanent magnet DC motor that is positioned by a direct digital control system. The scan carriage motion is mathematically modeled and simulated using ACSL and DADS simulation software. T he simulation results are compared to empirical data. It is shown that the dynamic response of the actual scan system can be predicted quite well using such simulations. Furthermore, these simulations can aid in the design of vibration-sensitive image formation devices

Suitability of the rgb Channels for a Pixel Manipulation in a Spatial Domain Data Hiding Techniques

The aim of this research was to determine which channel in rgb color space is the most suitable (regarding perceptibility) for a pixel manipulation in a spatial domain data hiding techniques. For this purpose three custom test targets were generated. The research also shows the behavior of two closely related colors in the ps (Print-Scan) process. The results are interpreted using both a quantitative method (statistical comparison) and a qualitative method (visual comparison)

Suitability of the rgb Channels for a Pixel Manipulation in a Spatial Domain Data Hiding Techniques

The aim of this research was to determine which channel in rgb color space is the most suitable (regarding perceptibility) for a pixel manipulation in a spatial domain data hiding techniques. For this purpose three custom test targets were generated. The research also shows the behavior of two closely related colors in the ps (Print-Scan) process. The results are interpreted using both a quantitative method (statistical comparison) and a qualitative method (visual comparison)

Digital Color Imaging

This paper surveys current technology and research in the area of digital color imaging. In order to establish the background and lay down terminology, fundamental concepts of color perception and measurement are first presented us-ing vector-space notation and terminology. Present-day color recording and reproduction systems are reviewed along with the common mathematical models used for representing these devices. Algorithms for processing color images for display and communication are surveyed, and a forecast of research trends is attempted. An extensive bibliography is provided

Liquid Foam-Ethyl Vinyl Acetate Adhesive Systems for Lining Process of Paintings: Prospects of a User-Friendly, Harmless Alternative to Conventional Products

The lining of paintings is a process of conservation science and art restoration used to strengthen, flatten, or consolidate paintings on canvas by attaching by means of adhesives a second canvas to the back of the existing one. To this aim, the prospects of the use of ethyl vinyl acetate (EVA) resins in aqueous dispersion applied as an adhesive in a foam form have been investigated in the present study. The key physical properties of the foam have been investigated, with a deep focus on rheological behavior and the drying rate, comparing the results with those obtained using the liquid products that are commercially available. Dedicated mock-ups have been prepared to test the adhesive for the lining process, inspecting adhesion strength, colorimetric properties, and the influence on the possible chromatic and visual alteration of the surface, also looking at the chemical interaction with painting materials and the deterioration after an artificial ageing process. The results obtained clearly indicated that the proposed technology is very suitable for the targeted application, and an EVA water-based foamed dispersion can be used for paintings' lining, in view of the ease of application, being an appropriate adhesion, no chemical interaction, nor the deterioration of the painting

Affective modulation of cognitive control is determined by performance-contingency and mediated by ventromedial prefrontal and cingulate cortex

Cognitive control requires a fine balance between stability, the protection of an on-going task-set, and flexibility, the ability to update a task-set in line with changing contingencies. It is thought that emotional processing modulates this balance, but results have been equivocal regarding the direction of this modulation. Here, we tested the hypothesis that a crucial determinant of this modulation is whether affective stimuli represent performance-contingent or task-irrelevant signals. Combining functional magnetic resonance imaging with a conflict task-switching paradigm, we contrasted the effects of presenting negative- and positive-valence pictures on the stability/flexibility trade-off in humans, depending on whether picture presentation was contingent on behavioral performance. Both the behavioral and neural expressions of cognitive control were modulated by stimulus valence and performance contingency: in the performance-contingent condition, cognitive flexibility was enhanced following positive pictures, whereas in the nonperformance-contingent condition, positive stimuli promoted cognitive stability. The imaging data showed that, as anticipated, the stability/flexibility trade-off per se was reflected in differential recruitment of dorsolateral frontoparietal and striatal regions. In contrast, the affective modulation of stability/flexibility shifts was mirrored, unexpectedly, by neural responses in ventromedial prefrontal and posterior cingulate cortices, core nodes of the “default mode” network. Our results demonstrate that the affective modulation of cognitive control depends on the performance contingency of the affect-inducing stimuli, and they document medial default mode regions to mediate the flexibility-promoting effects of performance-contingent positive affect, thus extending recent work that recasts these regions as serving a key role in on-task control processes