Capture, hold, release: an ontology of motion capture

In proposing an ontology of motion capture, this paper identifies three modalities — capture, hold, release — to conceptualise the peculiar affordances of motion capture technology in its relationship to a performer's movement. Motion capture is unique among contemporary moving image media in its capacity to re-perform a performer'srecorded movement a potentially limitless number of times, e.g. as applied to innumerable different CG characters. Unlike live-action film or even rotoscoping (motion capture's closest equivalent), the movement extracted from the captured performance lives on, but only by way of the inimagable (non-visible) domain of motion data.Motion data 'holds' movement itself in inimagable form, and 'releases' it in the domain of the digital moving image. This tri-fold conception relates an important dimension of (Heideggerian) Being to the idea of movement as fundamental to an ontology or 'being' of motion capture. At the same time, the proposed ontology challenges the 'illusion of life' metaphor as the accepted definition of (motion capture) animation.The Oscar's Special Rules for the Animated Feature Film Award asserts that 'by itself' motion capture does not qualify as an animation method. The notion that a technology could do or be anything 'by itself' affords a conceptual leap toward Heideggerian thinking on the nature of Being as embodied in temporality, in which past, present and future are unified.In its capacity to operate outside the domain of the digital moving image, the concept of 'movement itself' not only articulates an ontology of motion capture: motion capture itself can be understood to be brought into being by movement, thus also challenging the notion that capture technology has a parasitic relationship to a performer's originary performance.

Ontology of building in war and reconstruction

Post-war cities epitomise both a disjuncture and resonance between the end of the nation-state, on the one hand, and a preoccupation with reinventing the city through building, on the other. Programs of 'reconstruction' and 'remaking a city' are preceded by destruction: a destructive force has altered the face of the city, buildings have been destroyed and damaged, their ordered and ordering materiality is eroded, and the city is no longer an image of an idealized symbol of unity and identity. Belying the mythical power of architecture as a material and symbolic force, is also its fragility. Architecture can be monumentally erected and can have a presence and persistence that inspires awe and wonder, but it can also, just as easily be de-erected, demolished, destroyed. It can be de-constructed in a way that the literal sense of the term signals its symbolic frailty. Perceiving the symbolic as intrinsically tied to the physical articulation and presence of the architectural edifice, both reveals and conceals that the symbolic is also tied to fantasy, memory and fiction. Drawings that precede construction are projections of an idealized image of something that does not yet exist, and photographs that remain after a building is demolished are representations of a past realist that is now fictional.

Visual perception of movement kinematics and the acquisition of "action prototypes"

Recognizing a class of movements as belonging to a "nominal" action category, such as walking, running, or throwing, is a fundamental human ability. Three experiments were undertaken to test the hypothesis that common ("prototypical") features of moving displays could be learned by observation. Participants viewed moving stick-figure displays resembling forearm flexion movements in the saggital plane. Four displays (presentation displays) were first presented in which one or more movement dimensions were combined with 2 respective cues: direction (up, down), speed (fast, slow), and extent (long, short). Eight test displays were then shown, and the observer indicated whether each test display was like or unlike those previously seen. The results showed that without corrective feedback, a single cue (e.g., up or down) could be correctly recognized, on average, with the proportion correct between .66 and .87. When two cues were manipulated (e.g., up and slow), recognition accuracy remained high, ranging between .72 and .89. Three-cue displays were also easily identified. These results provide the first empirical demonstration of action-prototype learning for categories of human action and show how apparently complex kinematic patterns can be categorized in terms of common features or cues. It was also shown that probability of correct recognition of kinematic properties was reduced when the set of 4 presentation displays were more variable with respect to their shared kinematic property, such as speed or amplitude. Finally, while not conclusive, the results (from 2 of the 3 experiments) did suggest that similarity (or "likeness") with respect to a common kinematic property (or properties) is more easily recognized than dissimilarity.

Internal representation of movement in children with developmental coordination disorder : a mental rotation task

Recent studies show that children with developmental coordination disorder (DCD) have difficulties in generating an accurate visuospatial representation of an intended action, which are shown by deficits in motor imagery. This study sought to test this hypothesis further using a mental rotation paradigm. It was predicted that children with DCD would not conform to the typical pattern of responding when required to imagine movement of their limbs. Participants included 16 children with DCD and 18 control children; mean age for the DCD group was 10 years 4 months, and for controls 10 years. The task required children to judge the handedness of single-hand images that were presented at angles between 0° and 180° at 45° intervals in either direction. Results were broadly consistent with the hypothesis above. Responses of the control children conformed to the typical pattern of mental rotation: a moderate trade-off between response time and angle of rotation. The response pattern for the DCD group was less typical, with a small trade-off function. Response accuracy did not differ between groups. It was suggested that children with DCD, unlike controls, do not automatically enlist motor imagery when performing mental rotation, but rely on an alternative object-based strategy that preserves speed and accuracy. This occurs because these children manifest a reduced ability to make imagined transformations from an egocentric or first-person perspective.

A simplified stroke rehabilitation assessment of movement instrument

Background and Purpose. An efficient, reliable, and valid instrument for assessing motor function in patients with stroke is needed by both clinicians and researchers. To improve administration efficiency, we applied the multidimensional Rasch model to the 30-item, 3-subscale Stroke Rehabilitation Assessment of Movement (STREAM) instrument to produce a concise, reliable, and valid instrument (simplified STREAM [S-STREAM]) for measuring motor function in patients with stroke. Subjects and Methods. The STREAM (consisting of 3 subscales: upper-limb movements, lower-limb movements, and mobility) was administered to 351 subjects with first stroke occurrence and a median time after stroke of 19.5 months. The unidimensionality of each subscale of the STREAM first was verified with unidimensional Rasch analysis. Each subscale of the STREAM then was simplified by deleting redundant items on the basis of expert opinion and the results of the Rasch analysis. The Rasch reliability of the S-STREAM and the concurrent validity of the S-STREAM with the STREAM were examined with multidimensional Rasch analysis and the intraclass correlation coefficient (ICC), respectively. Results. After deleting the items that did not fit the Rasch model, we found that the 8-item upper-limb movement subscale, the 9-item lower-limb movement subscale, and the 10-item mobility subscale assessed single, unidimensional upper-limb movements, lower-limb movements, and mobility, respectively. We selected 5 items from each subscale to construct the S-STREAM and found that the reliability of each subscale of the resulting simplified instrument was high (Rasch reliability coefficients of [greater than or equal to] .91). The agreement between the subscale scores (Rasch estimates) of the S-STREAM and those of the STREAM was excellent (ICC of [greater than or equal to] .99, with a lower limit for the 95% confidence interval of [greater than or equal to] .985), indicating good concurrent validity of the S-STREAM with the STREAM. Discussion and Conclusion. The S-STREAM demonstrates high Rasch reliability, unidimensionality, and concurrent validity with the STREAM in patients with stroke. Furthermore, the S-STREAM is efficient to administer, as it consists of only half the number of items in the original STREAM. Additional studies to examine other psychometric properties (eg, predictive validity and responsiveness) of the S-STREAM or its psychometric properties in various recovery stages after stroke are needed to further establish its utility in both clinical and research settings.

Exhausting dance : performance and the politics of movement, by Andre Lepecki

The article reviews the book "Exhausting Dance: Performance and the Politics of Movement," by Andre Lepecki.

Assessment of movement participation for children with developmental coordination disorders

The Caregiver Assessment of Movement Participation was developed to identify children of 5-10 years old for movement participation difficulties in home contexts. Its psychometric properties were investigated including its usefulness as a screening instrument using both classical test theory methods and Rasch analysis. Results confirmed its validity and reliability.

Visual discrimination and reproduction of movement by individuals with an intellectual disability

This study investigates the capacity of individuals with an intellectual disability to make accurate discriminations of computer-generated displays and also to reproduce the characteristics of those displays. The findings suggest that the learning of everyday motor skills in this population may be hampered by difficulties in visually perceiving important characteristics of the demonstration. Procedures, employed for teaching these skills to intellectually disabled, are being reassessed in the light of these findings.

Screening children with developmental coordination disorder : the development of the caregiver assessment of movement participation

This study investigated the psychometric properties of the Caregiver Assessment of Movement Participation (CAMP), which was developed to measure and identify children with movement participation problems in home contexts. The test-retest reliability, as well as the concurrent and contrast-group validity of the 35-item parent-proxy CAMP, was examined on 312 children aged 5 to 8 years using intraclass correlation, factor analysis, and the Rasch model. Initial findings on the CAMP appeared to support its validity. Testing on other properties from a practical perspective, such as finding the best rating scale structure and cutpoints, are recommended before using the instrument for child health surveillance screening.

Psychometric properties of the caregiver assessment of movement participation scale for screening children with development coordination disorders

Using Rasch analysis, the psychometric properties of a newly developed 35-item parent-proxy instrument, the Caregiver Assessment of Movement Participation (CAMP), designed to measure movement participation problems in children with Developmental Coordination Disorder, were examined. The CAMP was administered to 465 school children aged 5–10 years. Thirty of the 35 items were retained as they had acceptable infit and outfit statistics. Item separation (7.48) and child separation (3.16) were good; moreover, the CAMP had excellent reliability (Reliability Index for item = 0.98; Person = 0.91). Principal components analysis of item residuals confirmed the unidimensionality of the instrument. Based on category probability statistics, the original five-point scale was collapsed into a four-point scale. The item threshold calibration of the CAMP with the Movement Assessment Battery for Children Test was computed. The results indicated that a CAMP total score of 75 is the optimal cut-off point for identifying children at risk of movement problems.

On the incremental learning and recognition of the pattern of movement of multiple labelled objects in dynamic scenes

In this paper we discuss combining incremental learning and incremental recognition to classify patterns consisting of multiple objects, each represented by multiple spatio-temporal features. Importantly the technique allows for ambiguity in terms of the positions of the start and finish of the pattern. This involves a progressive classification which considers the data at each time instance in the query and thus provides a probable answer before all the query information becomes available. We present two methods that combine incremental learning and incremental recognition: a time instance method and an overall best match method.