Pictorial Surface Research Articles

2D-3D Cognitive Tests Do Not Predict Laparoscopic Ability in Trainees Entering Post-Graduate Surgical Training

The manipulation of objects in 3D space while guided by 2D visual feedback is a key skill required for successful laparoscopic surgical performance. This has proven to be effortless and innate for some surgical trainees, but challenging for others to acquire. Some authors have reported associations between 2D-3D neuropsychological testing, Pic-torial Surface Orientation Test (PiSor) and innate laparoscopic ability. However, these findings either remain untested by independent centers or inconsistent.

Los colores subliminales en la obra de José Guerrero. Metodología y análisis para el deleite

Jose Guerrero’ s Art Centre collection shows a considerable number of paintings by this author, which are a great part of his artistic work. In the last years, thanks to the understanding and collaboration among different public entities, the controversy regarding the permanence of the collection in the museum has ended. A wide research has been done about the paintings through the colorimetrical study of its pictorial surfaces, which shows new artistic aspects of them. Some of these are: graduated shading in apparent stains of plain colours, linear limits or shades among different parts and, specially, areas with almost negligible colour through natural visual analysis. These have been shown thanks to the scientific methodology used. The research has also contributed to learn about the creative techniques, the colours and the expressivity of his paintings, verifying their quality. Their range of colours is visual stimulus that for many observers may seem consciously imperceptible due to their capacity of differenciating the colours shown. However, they may have an influence on the reactions the observers might experience when they contemplate the paintings because of the unconscious appreciation. The subliminal apparently appreciated and the synesthesia justify this phenomenon.

Colloid and Materials Science for the Conservation of Cultural Heritage: Cleaning, Consolidation, and Deacidification

Serendipity and experiment have been a frequent approach for the development of materials and methodologies used for a long time for either cleaning or consolidation of works of art. Recently, new perspectives have been opened by the application of materials science, colloid science, and interface science frameworks to conservation, generating a breakthrough in the development of innovative tools for the conservation and preservation of cultural heritage. This Article is an overview of the most recent contributions of colloid and materials science to the art conservation field, mainly focusing on the use of amphiphile-based fluids, gels, and alkaline earth metal hydroxide nanoparticles dispersions for the cleaning of pictorial surfaces, the consolidation of artistic substrates, and the deacidification of paper, canvas, and wood. Future possible directions for solving several conservation issues that still need to be faced are also highlighted.

Gels for the Conservation of Cultural Heritage

ABSTRACTThe consolidation of a pictorial surface or the removal of undesired material from the surface of an artifact, are the most important and delicate operations in the conservation of cultural heritage. In this contribution we report on the synthesis and characterization of two innovative systems for the cleaning of works of art: i) highly viscous polymeric dispersions (HVPDs) of poly(vinyl alcohol-co-vinyl acetate) random copolymer (PVAc), and ii) chemical gels from acrylamide - N,N’-methylene bisacrylamide, loaded with innovative aqueous cleaning systems. These systems were prepared, characterized and tested over artistic surfaces, such as wood and canvas. Rheology and FTIR spectroscopy allowed the characterization of the materials, and provided evidence that the systems allow an efficient cleaning of the substrates, without leaving residues.

Probing pictorial relief: from experimental design to surface reconstruction

The perception of pictorial surfaces has been studied quantitatively for more than 20 years. During this time, the “gauge figure method” has been shown to be a fast and intuitive method to quantify pictorial relief. In this method, observers have to adjust the attitude of a gauge figure such that it appears to lie flat on a surface in pictorial space. Although the method has received substantial attention in the literature and has become increasingly popular, a clear, step-by-step description has not been published yet. In this article, a detailed description of the method is provided: stimulus and sample preparation, performing the experiment, and reconstructing a 3-D surface from the experimental data. Furthermore, software (written in PsychToolbox) based on this description is provided in an online supplement. This report serves three purposes: First, it facilitates experimenters who want to use the gauge figure task but have been unable to design it, due to the lack of information in the literature. Second, the detailed description can facilitate the design of software for various other platforms, possibly Web-based. Third, the method described in this article is extended to objects with holes and inner contours. This class of objects have not yet been investigated with the gauge figure task.

Lightness Recovery for Pictorial Surfaces

We introduce a new formulation of the lightness problem for images of artworks, such as paintings or frescoes. As artists often paint the effects of light, the albedo field can contain a component that mimics an illumination field. Therefore, new insights are needed to distinguish the effects of physical illumination and painted shading. Because paint has a small dynamic range compared to light, these two signals can be distinguished using dynamic range. We describe a variational method to estimate the physical illumination component. We show our method produces estimates of the illumination intensity field for multispectral images of works of art that compare very well with ground truth, which is known. Our method outperforms other state-of-the art lightness recovery algorithms. For (R,G,B) images of frescoes found on the web, where ground truth is not known, our method produces results that appear to be very good, too.

The influence of object orientation and shading on pictorial relief of Lambertian surfaces

We studied the influence of object orientation and lighting direction on pictorial relief of 2D images of generic 3D objects. We used two objects, namely a globally convex object with a furrow in it and a globally convex object with a dimple in it. Participants adjusted a local surface attitude probe at 200-250 different locations in the image such that it seems to lie on the pictorial surface. In a 2×2 orthogonal design we manipulated the object orientation and the lighting direction. Lighting direction was always with respect to the view frame. The orientations were sufficiently altered to be qualitatively different from each other; that is, different kinds of shading singularities and contour singularities were present in the images. It was found that changes in lighting condition induced systematic changes on the settings for both orientations of the objects. First, the results showed that the reconstructed depth range was altered by a change in lighting direction. Second, we looked at the parabolic lines in the surface reconstructions; parabolic lines are curves on a surface where at least one of the principle curvatures equals zero. It was found that the parabolic lines shift due to a change in light direction. This is a particularly interesting finding since the actual location of the parabolic lines on the 3D object is invariant for changes in light direction and object orientation.

Perspective-Based Illusory Movement in a Flat Billboard—An Explanation

We describe a compelling motion illusion elicited by a huge billboard placed along a street, depicting a building that contains strong perspective cues. When observers move fast along the opposite sidewalk, they perceive the depicted building as rotating in their direction of travel. This is a special case of the 'following', or 'pointing out of the picture', illusion that elicits a strong illusory motion percept. Here we discuss the cause of the illusory motion and suggest that the brain relies on the depicted perspective cues to infer a 3-D shape and a concomitant motion that is incompatible with the physical pictorial surface.

Multispectral Acquisition of Large-Sized Pictorial Surfaces

Multispectral acquisition of artworks has recently received considerable attention in the image processing community. Quite understandably, so far this attention has mainly focused on paintings, given their predominant role in museum collections. It is worth pointing out that the instrumentation and procedures used for acquiring regular paintings are not suited for the multispectral acquisition of large-sized painted surfaces such as frescoed halls and great paintings. Given the relevance of such artifacts, and their widespread presence in churches or historical buildings due to their social function, the problem of finding suitable techniques for their acquisition is certainly worth addressing. This paper focuses on multispectral acquisition of large-sized pictorial surfaces, systematically addressing the practical issues related to the acquisition equipment and procedure. Given the crucial role played by the illumination in this application, special attention is given to this issue. The proposed approach is supported by experimental results.

Visuospatial Abilities Correlate With Performance of Senior Endoscopy Specialist in Simulated Colonoscopy

Visuospatial abilities have been demonstrated to predict the performance of medical students in simulated endoscopy. However, little has been reported whether differences in visuospatial abilities influence the performance of senior endoscopists or whether their vast endoscopy experience reduces the importance of these abilities. Eleven senior endoscopists were included in our study. Before the simulated endoscopies in GI Mentor II (gastroscopy: case 3, module 1 and colonoscopy: case 3, module 1), the endoscopists performed three visuospatial tests: (1) pictorial surface orientation (PicSOr), (2) card rotation, and (3) cube comparison tests that monitor the ability of the tested person to re-create a three-dimensional image from a two-dimensional presentation as well as mentally manipulate that re-created image. The results of the visuospatial tests were correlated to the performance parameters of the virtual-reality endoscopy simulator. The percent of time spent with clear view in the simulated colonoscopy correlated well with the performance in the visuospatial PicSOr (r = -0.75, P = 0.01), card rotation (r = 0.75, P = 0.01), and cube comparison (r = 0.79, P = 0.004) tests. The endoscopists who performed better in the visuospatial tests also were better at maintaining visualization of the colon lumen. Those who performed better in the PicSOr test formed fewer loops during colonoscopy (r = 0.60, P = 0.05). In the technically less demanding simulated gastroscopy, there were no such correlations. The visuospatial tests performed better in endoscopists not playing computer games. Good visuospatial ability correlates significantly with the performance of experienced endoscopists in a technically demanding simulated colonoscopy, but not in the less demanding simulated gastroscopy.

Monitoring of Pictorial Surfaces by mid‐FTIR Reflectance Spectroscopy: Evaluation of the Performance of Innovative Colloidal Cleaning Agents

This study reports the use of mid‐FTIR reflectance spectroscopy to evaluate the efficiency of an innovative method to remove aged polyacrylic resins from porous carbonate surfaces. Acrylic copolymers have been extensively used in recent decades as protectives and consolidants of frescoes. However, their aging produces both yellowing and serious degradation of painted layers, necessitating their removal. The evaluation of the performance of a method aimed to remove such aged polymers is often a crucial and critical problem. The innovative technique proposed here is based on the use of mid‐FTIR reflectance spectroscopy in optical fibers to check the reliability of an innovative colloidal cleaning agent, namely an oil‐in‐water microemulsion, constituted of a four‐component system consisting of water as the continuous phase, sodium dodecyl sulfate as the surfactant, 1‐pentanol as the cosurfactant, and p‐xylene as the dispersed phase. The efficacy of this innovative method has been tested first in the laboratory and then on the surface of a Renaissance fresco by Spinello Aretino in the Cappella Guasconi at San Francesco Cathedral (Arezzo, Italy). Through mid‐FTIR reflectance spectroscopic measurements performed in situ, the efficiency of the treatment has been proved, demonstrating that the nanotechnology approach represents a new, safe, and very efficient way of removing aged polymers from fresco surfaces.

The Influence of Illumination Direction on the Pictorial Reliefs of Lambertian Surfaces

In order to assess the influence of illumination direction on shape constancy, we studied the pictorial relief of computer images of globular 3-D objects. We used two globally convex objects, one with a furrow and one with a dimple. Observers adjusted local surface attitude probes at 200-250 different locations in the image such that they seemed to lie on the pictorial surface. We manipulated the viewing direction and the illumination direction in a 2 x 2 orthogonal design. Viewing directions were chosen such that the image contained only a few, or no, contour singularities. Changes in the illumination direction were found to induce systematic changes in the settings for both viewing directions. Effects were especially pronounced for images that had no contour singularities. The results showed that a change in the illumination direction can change the local shape of the pictorial relief in addition to the bas-relief ambiguities of scaling and shearing in depth. We found that concavities in the pictorial relief are associated with the darker areas in the image. The deviation from shape constancy cannot be explained by bas-relief ambiguity since the required transformation between the shapes is nonlinear.

Assessment of Construct Validity of the Endoscopic Sinus Surgery Simulator

To study the relationship between performance on an endoscopic sinus surgery simulator (ES3) and fundamental perceptual, visuospatial, and psychomotor abilities. Validation study. Tertiary care medical center. Thirty-four medical students and 4 otolaryngology residents voluntarily enrolled. Subjects performed tasks on the ES3, minimally invasive surgical trainer virtual reality (MIST-VR), pictorial surface orientation (PicSOr), and 3 visuospatial tests (cube comparison, card rotation, and map planning). The MIST-VR was scored for time, task error, economy of hand movement, economy of diathermy, and total score. Scores were generated for the PicSOr task and visuospatial tests. Scores were correlated with time, accuracy, and total subscore on navigation, injection, and dissection tasks, as well as hazard score and total trial score on the ES3. The PicSOr score was statistically significantly correlated with the hazard score on the ES3 (r = 0.50, P < .001). Cube comparison (r = 0.43, P < .01) and card rotation (r = 0.45, P < .01) scores correlated significantly with the ES3 trial score, as did the MIST-VR total score and the ES3 trial score (r = 0.57, P < .001). In a multiple regression model, the PicSOr, cube comparison, and MIST-VR total scores were statistically significant predictors of ES3 performance (r = 0.63, P < .01). Scores on the ES3 correlate strongly with scores on previously validated measures of perceptual, visuospatial, and psychomotor performance. The ES3 provides a reliable assessment of factors that are important to the acquisition of minimally invasive surgical skills, demonstrating construct validity.

'Participation TV': Early Games, Video Art, Abstraction and the Problem of Attention

This paper examines early videogames as part of a tradition in twentieth-century art. Looking at Pong (Atari, 1972) alongside works of Barnett Newman and Nam June Paik, I argue that this tradition grapples with the problem of attention: how to engender a deeper relationship, or an intimacy, between a playing body, mediating spaces or technologies and a pictorial surface. It is this relationship which is the locus of aesthetic practice - flattened, abstract depiction grounds experimentation with new media in visual, cognitive and haptic consumption, production and, progressively, co-production. Shading this with ambiguity is the consideration that games, and the rest of the tradition, can be seen as part of a disciplinary reconfiguration of attention along the lines of postindustrial production.

Taking Twofoldness Seriously: Walton on Imagination and Depiction

What experience are we supposed to go through experience. If an agent sees x in y, she is visually when looking at Malevich's painting, Red aware of both x and y simultaneously. As he puts House? two best-known accounts of this it: The seeing appropriate to representations experience were given by Richard Wollheim and permits simultaneous attention to what is repreKendall Walton. Wollheim's answer is that the sented and to the representation, to the object and experience is specific mode of perceptionto the medium.6 Walton repeatedly argues that seeing-in: we see red house in the surface of the his theory is consistent with the twofoldness painting.1 Walton, on the other hand, claims that claim.7 Moreover, he continues, his theory can be the surface of the painting is prop for what he regarded as an attempt to fill in the details of the calls a visual game of make-believe.2 On lookrather general and vague notion of twofoldness ing at the painting, we imagine our experience of Wollheim is using. He writes: the painting to be of the red house. These two accounts sound very different Seeing-in is an experience characterized by what indeed. However, Walton repeatedly insists that [Wollheim] calls twofoldness: one sees the marked his theory does not contradict Wollheim's, it picture surface, and one sees the subject of the rather complements it, specifies in more detail picture.... These are not two independent experiwhat the experience that constitutes representaences, he insists, but two aspects of single one. It is tional seeing (which he also calls seeing-in) is hard to know what this means, and Wollheim offers supposed to be.3 Wollheim, on the other hand, little explanation.... I propose that my theory goes denies that Walton's theory is consistent with some way towards showing how two different intenhis.4 It seems that one of them must be wrong. tional contents can be combined. experience is In this paper, I would like to analyze Walton's perception of the pictorial surface imagined to be latest attempt to explain why his theory is consistent perception of... whatever is depicted.8 with Wollheim's.5 More precisely, I will limit my attention to the notion of twofoldness. Two arguIn other words, according to Walton, his notion ments will be made. I will aim to point out that (1) of twofoldness can be seen as an interpretation Walton's notion of twofoldness is, in spite of what and explication of Wollheim's. Of course he Walton claims, very different from Wollheim's and uses this notion as key concept in his theory (2) Walton's notion of twofoldness is inconsistent of depiction, which is very different from with the rest of his theory of depiction. Wollheim's, but, at least according to Walton, his notion of twofoldness is consistent with Wollheim's. So let us see what Walton's notion of twofoldness is. Walton claims that seeing x in y is imagining most important feature of Wollheim's one's experience of y to be of x. two concept of seeing-in is the twofoldness of this folds of the twofoldness of this experience are

Kinds of Osmosis

Under the signature P.K. Irwin, poet P.K. Page has created a body of work in the visual arts. Exploring plastic concepts of rhythm and texture, she has composed surrealist landscapes, eerily suggestive and complexly layered. Notable for the architectonics of massing and subtle play of colour, her most powerful work has been in media such as oil pastel, egg tempera and pen and ink, which carry the energy of the artist’s gesture working and reworking the pictorial surface, building up brilliantly coloured layers, then sharply, intricately incising them with microscopic lines. Resonating on both aesthetic and psychological levels, her imagery constitutes a symbolic idiom through which to explore the nature and function of art. Seeing the world through the eye, she remarked, has taken her on a “journey from the material to the immaterial” (“Artist’s”).

A journey into pictorial space: Poetics of frame and field in Maithil painting

This article explores the ways in which Maithil painting is constituted in a plurality of contexts. Even though the painting is ephemeral on ceremonial occasions, the women artists take great care in composing it. Its formal structure always emphasises the dominance of the centre occupied by the vermilion dot around which the core motif (such as the lotus plant) is organised. As an ambulant object made for nobody in particular and at home everywhere, Maithil painting embodies a notion of portability and permanency during the commodity phase, which influences its formal structure in significant ways. For the first time the picto rial border is introduced to the painting. Along with new pictorial surfaces, colours and tools, the border has important implications for the organisation of the pictorial field. However, the concern for authenticity and meaning has led most scholars to overlook the complexities involved in the making of the painting, particularly such basic issues as frame and field, and foreground and background relationships. This article also tries to show that, despite these changes in the formal attributes of Maithil painting, the compositional structure continues to emphasise the dominance of centric tendencies within the pictorial field.

The framing effect with rectangular and trapezoidal surfaces: actual and pictorial surface slant, frame orientation, and viewing condition.

The perceived slant of a surface relative to the frontal plane can be reduced when the surface is viewed through a frame between the observer and the surface. Aspects of this framing effect were investigated in three experiments in which observers judged the orientations-in-depth of rectangular and trapezoidal surfaces which were matched for pictorial depth. In experiments 1 and 2, viewing was stationary-monocular. In experiment 1, a frontal rectangular frame was present or absent during viewing. The perceived slants of the surfaces were reduced in the presence of the frame; the reduction for the trapezoidal surface was greater, suggesting that conflict in stimulus information contributes to the phenomenon. In experiment 2, the rectangular frame was either frontal or slanted; in a third condition, a frame was trapezoidal and frontal. The conditions all elicited similar results, suggesting that the framing effect is not explained by pictorial perception of the display, or by assimilation of the surface orientation to the frame orientation. In experiment 3, viewing was moving-monocular to introduce motion parallax; the framing effect was reduced, being appreciable only for a trapezoidal surface. The results are related to other phenomena in which depth perception of points in space tends towards a frontal plane; this frontal-plane tendency is attributed to heavy experimental demands, mainly concerning impoverished, conflicting, and distracting information.

Pictorial surface attitude and local depth comparisons.

We measured local surface attitude for monocular pictorial relief and performed pairwise depth-comparison judgments on the same picture. Both measurements were subject to internal consistency checks. We found that both measurements were consistent with a relief (continuous pictorial surface) interpretation within the session-to-session scatter. We reconstructed the pictorial relief from both measurements separately, and found results that differed in detail but were quite similar in their basic structures. Formally, one expects certain geometrical identities that relate range and attitude data. Because we have independent measurements of both, we can attempt an empirical verification of such geometrical identities. Moreover, we can check whether the statistical scatter in the data indicates that, for example, the surface attitudes are derivable from a depth map or vice versa. We estimate that pairwise depth comparisons are an order of magnitude less precise than might be expected from the attitude data. Thus, the surface attitudes cannot be derived from a depth map as operationally defined by our methods, although the reverse is a possibility.

Editor's Introduction: Essays toward a New Art History

Like most fields the humanities, art history is caught up what is sometimes called (melodramatically) a crisis or revolution methods, aims, and theoretical foundations. Symptoms of this transformation are not difficult to see: an interest subaesthetic, marginal, and noncanonical artifacts; skepticism and self-consciousness about the discourse of art history and its claim to be called a history; a questioning of the ontological and semiotic status of the objects of art history, particularly their relation to language; a reexamination of standard models of the producer and beholder that questions the cult of the artist as individual genius and the spectator as a finely tuned but passive sensorium; a reconsideration of the traditional divisions of labor between art historian and art critic, or between the silent visual artist and the loquacious commentator. following articles are best described as essays in, not on, the New Art History. They exemplify what we regard as some of the most interesting new directions the practical understanding of art: the discourse of art historical description (David Summers); the materiality of the pictorial surface (Charles Harrison); the role of genre (Norman Bryson); the relation of visual representation and language (Robert Morris, Jan Baetens, and W. J. T. Mitchell); and the mediation of social and economic history through painting (Elizabeth Helsinger). These essays constitute a kind of first installment of work resulting from our call for papers The Disciplines of the Eye. This call continues to go out, and we shall welcome contributions that attempt to take stock of current thinking the visual arts a more general way-essays on as well as in the patterns of thought emerging the study of visual representation.