Evaluating the Historical Accuracy of Blackwork Embroidery with Fractal Analysis

The intricate monochromatic embroidery that graced the collars and cuffs of Renaissance nobility and domestic materials from that era has been little studied beyond the historical costuming and crafting communities. This style, known as blackwork, for it was traditionally done in black silk on white linen, exemplifies how complex and visually-appealing designs can arise from repetition of simple forms, often demonstrating the fractal property of self-similarity. Though most blackwork patterns are not true fractals, fractal analysis offers a means of objectively quantifying their complexity and new lens through which to examine this embroidery technique. The purpose of this study was to look for trends that could be used to evaluate the historical accuracy of blackwork patterns. Images of historical patterns from the Renaissance period, historically-inspired, and modern patterns were gathered from eight published books on blackwork. The fractal dimensions of these patterns were calculated using FracLac, a fractal analysis plugin for the ImageJ software. Subsequent statistical analyses revealed several significant differences between the fractal dimensions of patterns for fillings, borders, and complete projects. Though there was some variation, a trend noted was that Renaissance-era patterns had a fractal dimension around 1.75

Visual art inspired by the collective feeding behavior of sand-bubbler crabs

Sand--bubblers are crabs of the genera Dotilla and Scopimera which are known to produce remarkable patterns and structures at tropical beaches. From these pattern-making abilities, we may draw inspiration for digital visual art. A simple mathematical model is proposed and an algorithm is designed that may create such sand-bubbler patterns artificially. In addition, design parameters to modify the patterns are identified and analyzed by computational aesthetic measures. Finally, an extension of the algorithm is discussed that may enable controlling and guiding generative evolution of the art-making process

Macaques preferentially attend to visual patterns with higher fractal dimension contours.

Animals' sensory systems evolved to efficiently process information from their environmental niches. Niches often include irregular shapes and rough textures (e.g., jagged terrain, canopy outlines) that must be navigated to find food, escape predators, and master other fitness-related challenges. For most primates, vision is the dominant sensory modality and thus, primates have evolved systems for processing complicated visual stimuli. One way to quantify information present in visual stimuli in natural scenes is evaluating their fractal dimension. We hypothesized that sensitivity to complicated geometric forms, indexed by fractal dimension, is an evolutionarily conserved capacity, and tested this capacity in rhesus macaques (Macaca mulatta). Monkeys viewed paired black and white images of simulated self-similar contours that systematically varied in fractal dimension while their attention to the stimuli was measured using noninvasive infrared eye tracking. They fixated more frequently on, dwelled for longer durations on, and had attentional biases towards images that contain boundary contours with higher fractal dimensions. This indicates that, like humans, they discriminate between visual stimuli on the basis of fractal dimension and may prefer viewing informationally rich visual stimuli. Our findings suggest that sensitivity to fractal dimension may be a wider ability of the vertebrate vision system

Overlap-free Drawing of Generalized Pythagoras Trees for Hierarchy Visualization

Generalized Pythagoras trees were developed for visualizing hierarchical data, producing organic, fractal-like representations. However, the drawback of the original layout algorithm is visual overlap of tree branches. To avoid such overlap, we introduce an adapted drawing algorithm using ellipses instead of circles to recursively place tree nodes representing the subhierarchies. Our technique is demonstrated by resolving overlap in diverse real-world and generated datasets, while comparing the results to the original approach

Aesthetic image statistics vary with artistic genre

Research to date has not found strong evidence for a universal link between any single low-level image statistic, such as fractal dimension or Fourier spectral slope, and aesthetic ratings of images in general. This study assessed whether different image statistics are important for artistic images containing different subjects and used partial least squares regression (PLSR) to identify the statistics that correlated most reliably with ratings. Fourier spectral slope, fractal dimension and Shannon entropy were estimated separately for paintings containing landscapes, people, still life, portraits, nudes, animals, buildings and abstracts. Separate analyses were performed on the luminance and colour information in the images. PLSR fits showed shared variance of up to 75% between image statistics and aesthetic ratings. The most important statistics and image planes varied across genres. Variation in statistics may reflect characteristic properties of the different neural sub-systems that process different types of image

Human Preference and Fractal Dimension

The objective of this study is to assess any connections between the fractal dimension of edges in images of pastoral landscapes in Sweden and preference rating of the images and preference ratings for the edge images respectively. 23 participants volunteered for the trial. The mean age was 29,95 years, six of the subjects where women. The study consited of analysis of fractal dimension in images of pastoral landscapes from an earlier study and an experiment with human participants. The subjects estimated their preference for manipulated images, edge images, of pastoral landscapes. Their results where compared to results from the earlier study on non manipulated images. The result show that significant connection exists and in a way that correlates well with earlier studies. The edge images did not have significant correlation. Results for the edge images: (rs = 0.015, p<0.0001), and the original images: (rs = -0.853, p<0.0001). Furthermore the study discuss the concept “preference” and however that concept needs to be more defined if it is to be useful.

Beauty in Snowflakes: Complexity and Visual Aesthetics

Experimental aesthetics research has been conducted since the nineteenth century. Interestingly, however, few studies have examined the perceived beauty of naturally shaped objects. In the current experiment, 204 participants were presented with a set of ten snowflake silhouettes that varied in complexity (perimeter relative to area); they were similarly presented with ten randomly-shaped, computer-generated, solid objects that also varied in complexity. For each stimulus set, the participants selected the single snowflake or object that was the most beautiful (Fechner’s method of choice). The results for the solid objects replicated the findings of earlier research: the most and least complex objects were chosen as the most beautiful. Moderately complex objects were rarely selected. The results for the snowflakes were different. For these visual stimuli, the least complex snowflakes were almost never chosen; only the complex snowflakes were perceived to be most beautiful, with the aesthetic preference increasing with increases in complexity

Temporal Structure of Human Gaze Dynamics is Invariant During Free Viewing

We investigate the dynamic structure of human gaze and present an experimental study of the frequency components of the change in gaze position over time during free viewing of computer-generated fractal images. We show that changes in gaze position are scale-invariant in time with statistical properties that are characteristic of a random walk process. We quantify and track changes in the temporal structure using a well-defined scaling parameter called the Hurst exponent, H. We find H is robust regardless of the spatial complexity generated by the fractal images. In addition, we find the Hurst exponent is invariant across all participants, including those with distinct changes to higher order visual processes due to neural degeneration. The value we find for H of 0.57 shows that the gaze dynamics during free viewing of fractal images are consistent with a random walk process with persistent movements. Our research suggests the human visual system may have a common strategy that drives the dynamics of human gaze during exploration