Stick Figure Research Articles

Creating Stick Figure Animations Based on Captured Motion Data

Creating Stick Figure Animations Based on Captured Motion Data

The Context of Critical Design: Exhibits, Social Media and Auction Houses

ABSTRACTCritical design and design for debate seek to critique contemporary society through the production of provocative artefacts that cause the viewer to reflect on current trends, assumptions and values. But such designs are typically displayed in relatively elitist contexts – art galleries, conference halls and academic publications. Many designers are now making short films of their work and posting them to sites like Vimeo and YouTube. This paper considers such sites as potential spaces for widening the context of critical design. It describes responses on YouTube to three videos of designs by Freddie Yauner. The Fastest Clock in the World is a clock that gives time to a millionth of a second, The Highest Popping Toaster in the World uses a compressed gas-powered mechanism to fire toast at the ceiling, Signs of Life appears to be a fire exit sign until the stick figure running for the door begins to yawn, stretch and wander out of shot to take a break. A film of each was posted to YouTube and the comments were analysed to consider the extent to which social media can be used to extend and promote the kinds of debate that critical design seeks to create. The paper outlines a method for analysing YouTube data which draws on site statistics, content analysis, grounded theory and critical theory. Viewing figures and comments indicate that such social media do have the potential to enlarge the audience for critical design although engagement may be relatively superficial. The paper argues that while critical design artefacts critique consumer society this does not prevent them from themselves becoming desirable objects to be consumed. It suggests that the context of critical design must be expanded if it is to escape this deadlock.

Art to Smart: An Automated Bharatanatyam Dance Choreography

The ancient Indian classical dance form BharataNatyam (BN) can stay alive and dynamic by allowing innovative, experimental ideas. These comprise of a sequence of possible and legitimate dance steps, and it is estimated that using the main body parts, namely head, neck, hands and legs, more than five lakh dance steps can be generated for a single beat. Thus, dance choreography becomes an intensive, creative, and intuitive process. A choreographer has to finalize appropriate dance steps from among millions of possibilities. Though it is not impossible, the human choreographer cannot explore, analyze and remember all these variations among steps because of the large number of available options.Hence, we propose to develop an autoenumeration followed by autoclassification of significant BN dance steps that can be used in dance performance and choreography. The foremost and most challenging task is to have a computational model that represents different BN dance poses. The second task is to develop a genetic algorithm (GA)-driven automatic system that would provide choreographers a list of unexplored, novel dance steps to fit in a single beat. We designed Art to SMart as a system to model the dance art of BharataNatyam. This system generates dance poses. Furthermore, we have developed a stick figure generation module to help visualize the 30-attribute dance vector generated from the system. The results are evaluated using a mean opinion score measure.

Misrepresentation in tsunami warning signage: iconic denial

[B]lue and white signs depict ... a series of waves and a stick figure running uphill that alert residents and visitors to the fact that they are in a tsunami-vulnerable area. These tsunami warning signs, which were created as part of an Oregon Sea Grant effort, have spread not only to other U.S. states and territories, but also to other countries ... ‘it’s certainly gratifying [to see] how it’s caught on’ says emeritus Professor Jim Good. (Goss 2008, 7).

Evaluating visual query methods for articulated motion video search

We develop and evaluate three interfaces for video search of articulated objects, specifically humans performing common actions. The three interfaces, (1) a freehand interface with motion cues (e.g., arrows), (2) an articulated human stick figure with motion cues, and (3) a keyframe interface, were designed to allow users to quickly generate motion-based queries. We performed both quantitative and qualitative analyses of the interfaces through a formal user study by measuring accuracy and speed of user input and asking the users to complete a free-response questionnaire. Our results indicate that the constrained interfaces outperform the freehand sketch-based interface, in terms of both search accuracy and query completion time. Additionally, the users described strong preferences for the search interfaces containing pre-defined models, and the generated queries were rated higher, in terms of semantic matches to the query concept.

What causes the facing-the-viewer bias in biological motion?

Orthographically projected biological motion point-light displays are generally ambiguous with respect to their orientation in depth, yet observers consistently prefer the facing-the-viewer interpretation. There has been discussion as to whether this bias can be attributed to the social relevance of biological motion stimuli or relates to local, low-level stimulus properties. In the present study we address this question. In Experiment 1, we compared the facing-the-viewer bias produced by a series of four stick figures and three human silhouettes that differed in posture, gender, and the presence versus absence of walking motion. Using a paradigm in which we asked observers to indicate the spinning direction of these figures, we found no bias when participants observed silhouettes, whereas a pronounced degree of bias was elicited by most stick figures. We hypothesized that the ambiguous surface normals on the lines and dots that comprise stick figures are prone to a visual bias that assumes surfaces to be convex. The local surface orientations of the occluding contours of silhouettes are unambiguous, and as such the convexity bias does not apply. In Experiment 2, we tested the role of local features in ambiguous surface perception by adding dots to the elbows and knees of silhouettes. We found biases consistent with the facing directions implied by a convex body surface. The results unify a number of findings regarding the facing-the-viewer bias. We conclude that the facing-the-viewer bias is established at the level of surface reconstruction from local image features rather than on a semantic level.

Significant body point labeling and tracking.

In this paper, a method is presented to label and track anatomical landmarks (e.g., head, hand/arm, feet), which are referred to as significant body points (SBPs), using implicit body models. By considering the human body as an inverted pendulum model, ellipse fitting and contour moments are applied to classify it as being in Stand, Sit, or Lie posture. A convex hull of the silhouette contour is used to determine the locations of SBPs. The particle filter or a motion flow-based method is used to predict SBPs in occlusion. Stick figures of various activities are generated by connecting the SBPs. The qualitative and quantitative evaluation show that the proposed method robustly labels and tracks SBPs in various activities of two different (low and high) resolution data sets.

Stick figures and point-light displays: Effects of inversion on the facing-the-viewer bias

Stick figures and point-light displays: Effects of inversion on the facing-the-viewer bias

Both physical exercise and progressive muscle relaxation reduce the facing-the-viewer bias in biological motion perception.

Biological motion stimuli, such as orthographically projected stick figure walkers, are ambiguous about their orientation in depth. The projection of a stick figure walker oriented towards the viewer, therefore, is the same as its projection when oriented away. Even though such figures are depth-ambiguous, however, observers tend to interpret them as facing towards them more often than facing away. Some have speculated that this facing-the-viewer bias may exist for sociobiological reasons: Mistaking another human as retreating when they are actually approaching could have more severe consequences than the opposite error. Implied in this hypothesis is that the facing-towards percept of biological motion stimuli is potentially more threatening. Measures of anxiety and the facing-the-viewer bias should therefore be related, as researchers have consistently found that anxious individuals display an attentional bias towards more threatening stimuli. The goal of this study was to assess whether physical exercise (Experiment 1) or an anxiety induction/reduction task (Experiment 2) would significantly affect facing-the-viewer biases. We hypothesized that both physical exercise and progressive muscle relaxation would decrease facing-the-viewer biases for full stick figure walkers, but not for bottom- or top-half-only human stimuli, as these carry less sociobiological relevance. On the other hand, we expected that the anxiety induction task (Experiment 2) would increase facing-the-viewer biases for full stick figure walkers only. In both experiments, participants completed anxiety questionnaires, exercised on a treadmill (Experiment 1) or performed an anxiety induction/reduction task (Experiment 2), and then immediately completed a perceptual task that allowed us to assess their facing-the-viewer bias. As hypothesized, we found that physical exercise and progressive muscle relaxation reduced facing-the-viewer biases for full stick figure walkers only. Our results provide further support that the facing-the-viewer bias for biological motion stimuli is related to the sociobiological relevance of such stimuli.

Emotion categorization of body expressions in narrative scenarios.

Humans can recognize emotions expressed through body motion with high accuracy even when the stimuli are impoverished. However, most of the research on body motion has relied on exaggerated displays of emotions. In this paper we present two experiments where we investigated whether emotional body expressions could be recognized when they were recorded during natural narration. Our actors were free to use their entire body, face, and voice to express emotions, but our resulting visual stimuli used only the upper body motion trajectories in the form of animated stick figures. Observers were asked to perform an emotion recognition task on short motion sequences using a large and balanced set of emotions (amusement, joy, pride, relief, surprise, anger, disgust, fear, sadness, shame, and neutral). Even with only upper body motion available, our results show recognition accuracy significantly above chance level and high consistency rates among observers. In our first experiment, that used more classic emotion induction setup, all emotions were well recognized. In the second study that employed narrations, four basic emotion categories (joy, anger, fear, and sadness), three non-basic emotion categories (amusement, pride, and shame) and the “neutral” category were recognized above chance. Interestingly, especially in the second experiment, observers showed a bias toward anger when recognizing the motion sequences for emotions. We discovered that similarities between motion sequences across the emotions along such properties as mean motion speed, number of peaks in the motion trajectory and mean motion span can explain a large percent of the variation in observers' responses. Overall, our results show that upper body motion is informative for emotion recognition in narrative scenarios.

Innate pattern recognition and categorization in a jumping spider.

The East African jumping spider Evarcha culicivora feeds indirectly on vertebrate blood by preferentially preying upon blood-fed Anopheles mosquitoes, the vectors of human malaria1, using the distinct resting posture and engorged abdomen characteristic of these specific prey as key elements for their recognition. To understand perceptual categorization of objects by these spiders, we investigated their predatory behavior toward different digital stimuli - abstract ‘stick figure’ representations of Anopheles constructed solely by known key identification elements, disarranged versions of these, as well as non-prey items and detailed images of alternative prey. We hypothesized that the abstract images representing Anopheles would be perceived as potential prey, and would be preferred to those of non-preferred prey. Spiders perceived the abstract stick figures of Anopheles specifically as their preferred prey, attacking them significantly more often than non-preferred prey, even when the comprising elements of the Anopheles stick figures were disarranged and disconnected from each other. However, if the relative angles between the elements of the disconnected stick figures of Anopheles were altered, the otherwise identical set of elements was no longer perceived as prey. These data show that E. culicivora is capable of making discriminations based on abstract concepts, such as the hypothetical angle formed by discontinuous elements. It is this inter-element angle rather than resting posture that is important for correct identification of Anopheles. Our results provide a glimpse of the underlying processes of object recognition in animals with minute brains, and suggest that these spiders use a local processing approach for object recognition, rather than a holistic or global approach. This study provides an excellent basis for a comparative analysis on feature extraction and detection by animals as diverse as bees and mammals.

Love, Loss, and Water: A Meditation on a Metaphor

I once spent an entire day on a crowded observation deck watching Patagonia's largest advancing glacier, Perito Moreno, calve into the water. This is a glacier described as “defiant” for its continued growth in a warming world, as if ice melts due to weakness of character. I didn't want to pay the extra money to take a boat ride around Lago Argentina, its bright blue surface scattered with floating chunks of discarded ice, so I was limited to one vantage point and an unending soundtrack of multilinguistic tourist chatter. It was quite boring after a while: too much time to passively sit and stare, and too little time to witness any significant changes in global climate patterns. I thought a lot about food during those hours. But there was only one daily bus between the town and the glacier, and I reminded myself that there might not be glaciers when I'm old. At one end of the observation deck, a hand-painted sign warning tourists not to climb the railing depicted an image of an ice projectile impaling a startled stick figure's head. So I stayed on the deck, watching, hour after hour, trying to focus on the privilege of sharing the world with ice rather than fantasizing about what I'd eat when I got back to town.

Designing modular reaction-diffusion programs for complex pattern formation

Cells use sophisticated, multiscale spatial patterns of chemical instructions to control cell fate and tissue growth. While some types of synthetic pattern formation have been well studied1-6, it remains unclear how to design chemical processes that can reproducibly create similar spatial patterns. Here we describe a scalable approach for the design of processes that generate such patterns, which can be implemented using synthetic DNA reaction-diffusion networks7,8. In our method, black-box modules are connected together into integrated programs for arbitrarily complex pattern formation. These programs can respond to input stimuli, process information, and ultimately produce stable output patterns that differ in size and concentration from their inputs. To build these programs, we break a target pattern into a set of patterning subtasks, design modules to perform these subtasks independently, and combine the modules into networks. We demonstrate in simulation how programs designed with our methodology can generate complex patterns, including a French flag and a stick figure.

Neural responses to cartoon facial attractiveness: An event-related potential study

Animation creates a vivid, virtual world and expands the scope of human imagination. In this study, we investigated the time-courses of brain responses related to the evaluation of the attractiveness of cartoon faces using the event-related potential (ERP) technique. The results demonstrated that N170 amplitude was higher for attractive than for unattractive cartoon faces in males, while the opposite was found in females. Facial attractiveness notably modulated the late positive component (LPC), which might reflect the task-related process of aesthetic appraisal of beauty. The mean LPC amplitude in males was significantly higher for attractive cartoon faces than for unattractive faces, while the LPC amplitude in females did not significantly differ between attractive and unattractive cartoon faces. Moreover, the paint mode (computer graphics, gouache, and stick figure) modulated the early encoding of facial structures and the late evaluative process. The early modulation effect by paint mode may be related to the spatial frequency of the pictures. The processing speed and intensity in females were both higher than those in males. In conclusion, our study, for the first time, reported ERP modulation based on the assessment of cartoon facial attractiveness, suggesting the facilitated selection of attractiveness information at the early stage, and that the attentional enhancement of attractive faces at the late stage only exists in males. This suggests that men's brains are hard-wired to be sensitive to facial beauty, even in cartoons.

Acquisition a Baseball-Pitch through Observation: What Information Is Extracted?

The purpose of the present study was to compare the relative effects of observing video, stick figure and point-light model demonstrations on acquisition a Baseball pitch. Participants (ns = 41) in demonstration and control groups performed 5 trials in pretest, three blocks of 10 trials in acquisition phase, and two retention tests of 5 trials in 10 minutes and one week later. Participants´ performances were assessed by two raters at the level of overall movement and individual movement phases. Results showed similarities between demonstration groups in acquisition phase and early retention test. Participants showed a significant improvement in stride and follow-through phases from pretest to acquisition blocks. The findings are discussed in terms of theoretical and methodological backgrounds.

Inversion effects in the perception of the moving human form: A comparison of adolescents with autism spectrum disorder and typically developing adolescents

The "body inversion effect" refers to superior recognition of upright than inverted images of the human body and indicates typical configural processing. Previous research by Reed et al. using static images of the human body shows that people with autism fail to demonstrate this effect. Using a novel task in which adults, adolescents with autism, and typically developing adolescents judged whether walking stick figures-created from biological motion recordings and shown at seven orientations between 0° and 180°-were normal or distorted, this study shows clear effects of stimulus inversion. Reaction times and "inverse efficiency" increased with orientation for normal but not distorted walkers, and sensitivity declined with rotation from upright for all groups. Notably, the effect of stimulus inversion was equally detrimental to both groups of adolescents suggesting intact configural processing of the body in motion in autism spectrum disorder.

Teaching Chaucer and Popular Culture:

This essay is inspired both by an increasing disciplinary contention that Chaucerians engage with popular culture and by a refreshed critical interest (reflected in the burgeoning field of the Scholarship of Teaching and Learning) in sharing pedagogical innovations and interests with peers within a public forum.2 Notwithstanding lingering professional suspicions about the value of the popular, engagement with popular culture involves the need both to better communicate Chaucer’s aesthetic distinction to the culture at large and to embrace the popular in our teaching. This essay offers a brief meditation on the value of the popular and offers two theoretical approaches that one might use to introduce the study of Chaucer’s popular constructions into the classroom. I suggest, in short, that Chaucer’s reproduction in popular culture has both pedagogical and critical value—both as interpretations of his poetry as it is adapted to

Danny's Doodles: The Jellybean Experiment by David A. Adler (review)

Reviewed by: Danny's Doodles: The Jellybean Experiment by David A. Adler Thaddeus Andracki Adler, David A. Danny's Doodles: The Jellybean Experiment; written and illus. by David A. Adler. Sourcebooks, 2013. [112p]. Paper ed. ISBN 978-1-4022-8721-3 $4.99 Reviewed from galleys R Gr. 2-4. The new kid in Danny's class, Calvin Waffle, is friendly enough, but he's a little weird: he's asked Danny to keep a massive bag of jellybeans in his pockets for [End Page 70] a week as part of an unexplained experiment. When Calvin invites Danny and some classmates to his house for a homework party, he reveals that his experiment was designed to see if smelling like jellybeans would make Danny more popular (it worked), and the group discovers that Calvin's actually a really perceptive and kind-hearted guy in spite of his quirks. Adler adds some depth to the befriend-the-new-kid story with inventive phrasing, humorous characterization, and a gentle backstory about Calvin's absent father. Although some more complex vocabulary might push this toward stronger readers or reading aloud, moderately oversized text and manageable, chunky chapters enhance readability, and the doodles that lend this series its name pepper the text in the form of cleverly captioned squiggles and stick figures. Danny and Calvin are classic non-superhero chapter book protagonists, and they're remarkably easy to relate to; the factual information about experimentation might also make this an interesting literature complement to a classroom study of the scientific method. Copyright © 2013 The Board of Trustees of the University of Illinois

Electrophysiological markers of biological motion and human form recognition

Current models suggest that human form and motion information are initially processed through separate pathways, then integrated in action perception. Testing such a sequential model requires techniques with high temporal resolution. Prior work demonstrated sensitivity of a posterior temporal event-related potential (ERP) effect — the N2 — to biological motion, but did not test whether the N2 indexes biological motion perception specifically, or human form/action perception more generally. We recorded ERPs while participants viewed stimuli across 3 blocks: (1) static (non-moving) point-light displays of humans performing actions; (2) static stick figures with clear forms; and (3) point-light biological motion. A similar sequence of ERP components was elicited by human forms in all blocks (stationary and moving), and reliably discriminated between human and scrambled forms. The N2 showed similar scalp distribution and sensitivity to stimulus manipulations for both stick figures and biological motion, suggesting that it indexes integration of form and motion information, rather than biological motion perception exclusively — and that form and motion information are therefore integrated by approximately 200ms. We identified a component subsequent to the N2, which we label the medial parietal positivity/ventral–anterior negativity (MPP/VAN), that was also sensitive to both human form and motion information. We propose that the MPP/VAN reflects higher-order human action recognition that occurs subsequent to the integration of form and motion information reflected by the N2.

Older Adults’ Perceptions of Pictograph-Based Discharge Instructions after Hip Replacement Surgery

Current text-based discharge instructions are unsuitable for low-literate older adults who have difficulty following written action-based instructions. To address this issue, we developed discharge instructions for low-literate older adults after hip replacement surgery using pictographs (i.e., simple line drawings with stick figures showing explicit care actions). The aim of this focus group study was to examine the acceptability and comprehension of these instructions to 15 low-literate older adults. Participants perceived that the pictograph-based discharge instructions helped them understand the intended health care messages, especially for step-by-step procedures of discharge actions. The black-and-white line drawings were well received by all participants of various race/ethnicity. A pictograph-based approach is an effective strategy for developing discharge instructions not only for patients with low literacy skills in acute health care settings, but also for immigrants with significant communication challenges. Future research is suggested to compare the effects of pictograph-based and text-based instructions on adherence to instructions and health outcomes.