The spatiotemporal representation of dance and music gestures using topological gesture analysis (TGA)

SPATIOTEMPORAL GESTURES IN MUSIC AND DANCE HAVE been approached using both qualitative and quantitative research methods. Applying quantitative methods has offered new perspectives but imposed several constraints such as artificial metric systems, weak links with qualitative information, and incomplete accounts of variability. In this study, we tackle these problems using concepts from topology to analyze gestural relationships in space. The Topological Gesture Analysis (TGA) relies on the projection of musical cues onto gesture trajectories, which generates point clouds in a three-dimensional space. Point clouds can be interpreted as topologies equipped with musical qualities, which gives us an idea about the relationships between gesture, space, and music. Using this method, we investigate the relationships between musical meter, dance style, and expertise in two popular dances (samba and Charleston). The results show how musical meter is encoded in the dancer's space and how relevant information about styles and expertise can be revealed by means of simple topological relationships

Representation of Samba dance gestures, using a multi-modal analysis approach

In this paper we propose an approach for the representation of dance gestures in Samba dance. This representation is based on a video analysis of body movements, carried out from the viewpoint of the musical meter. Our method provides the periods, a measure of energy and a visual representation of periodic movement in dance. The method is applied to a limited universe of Samba dances and music, which is used to illustrate the usefulness of the approach

Basic gestures as spatiotemporal reference frames for repetitive dance/music patterns in samba and charleston

THE GOAL OF THE PRESENT STUDY IS TO GAIN BETTER insight into how dancers establish, through dancing, a spatiotemporal reference frame in synchrony with musical cues. With the aim of achieving this, repetitive dance patterns of samba and Charleston were recorded using a three-dimensional motion capture system. Geometric patterns then were extracted from each joint of the dancer's body. The method uses a body-centered reference frame and decomposes the movement into non-orthogonal periodicities that match periods of the musical meter. Musical cues (such as meter and loudness) as well as action-based cues (such as velocity) can be projected onto the patterns, thus providing spatiotemporal reference frames, or 'basic gestures,' for action-perception couplings. Conceptually speaking, the spatiotemporal reference frames control minimum effort points in action-perception couplings. They reside as memory patterns in the mental and/or motor domains, ready to be dynamically transformed in dance movements. The present study raises a number of hypotheses related to spatial cognition that may serve as guiding principles for future dance/music studies

Sonification of Samba dance using periodic pattern analysis

In this study we focus on the sonification of Samba dance, using a multi-modal analysis-by-synthesis approach. In the analysis we use periodic pattern analysis to decompose the Samba dance movements into basic movement gestures along the music’s metric layers. In the synthesis we start from the basic movement gestures and extract peaks and valleys, which we use as basic material for the sonification. This leads to a matrix of repetitive dance gestures from which we select the proper cues that trigger samples of a Samba ensemble. The straightforward sonification procedure suggests that Samba rhythms may be mirrored in choreographic forms or vice-versa

Accessing structure of samba rhythms through cultural practices of vocal percussions

In the field of computer music, melodic based forms of vocalizations have often been used as channels to access subject’s queries and retrieve information from music databases. In this study, we look at percussive forms of vocalizations in order to retrieve rhythmic models entrained by subjects in Samba culture. By analyzing recordings of vocal percussions collected from randomly selected Brazilian subjects, we aim at comparing emergent rhythmic structures with the current knowledge about Samba music forms. The database of recordings was processed using a psychoacoustically inspired auditory model and further displayed on loudness and onset images. The analyses of emergent rhythmic patterns show intriguing similarities with the findings in previous studies in the field and put different perspectives on the use of vocal forms in music information retrieval and musicology

Synthesis of variable dancing styles based on a compact spatiotemporal representation of dance

Dance as a complex expressive form of motion is able to convey emotion, meaning and social idiosyncrasies that opens channels for non-verbal communication, and promotes rich cross-modal interactions with music and the environment. As such, realistic dancing characters may incorporate crossmodal information and variability of the dance forms through compact representations that may describe the movement structure in terms of its spatial and temporal organization. In this paper, we propose a novel method for synthesizing beatsynchronous dancing motions based on a compact topological model of dance styles, previously captured with a motion capture system. The model was based on the Topological Gesture Analysis (TGA) which conveys a discrete three-dimensional point-cloud representation of the dance, by describing the spatiotemporal variability of its gestural trajectories into uniform spherical distributions, according to classes of the musical meter. The methodology for synthesizing the modeled dance traces back the topological representations, constrained with definable metrical and spatial parameters, into complete dance instances whose variability is controlled by stochastic processes that considers both TGA distributions and the kinematic constraints of the body morphology. In order to assess the relevance and flexibility of each parameter into feasibly reproducing the style of the captured dance, we correlated both captured and synthesized trajectories of samba dancing sequences in relation to the level of compression of the used model, and report on a subjective evaluation over a set of six tests. The achieved results validated our approach, suggesting that a periodic dancing style, and its musical synchrony, can be feasibly reproduced from a suitably parametrized discrete spatiotemporal representation of the gestural motion trajectories, with a notable degree of compression

Multidimensional microtiming in Samba music

The connection of “groove” with low-level features in the audio signal has been mostly associated with temporal characteristics of fast metrical structures. However, the production and perception of rhythm in Afro-Brazilian contexts is often described as a result of multiple experience flows, which expands the description of rhythmical events to multiple features such as loudness, spectrum regions, metrical layers, movement and others. In this study, we analyzed how the microtiming of samba music interacts with an expanded set of musical descriptors. More specifically, we analyzed the interaction between fast timing structures with meter, intensity and spectral distribution within the auditory domain. The methodology for feature detection was supported by a psychoacoustically based auditory model, which provided the low-level descriptors for a database of 106 samba music excerpts. A cluster analysis technique was used to provide an overview of emergent microtiming models present in the features. The results confirm findings of previous studies in the field but introduce new systematic devices that may characterize microtiming in samba music. Systematic models of interactions between microtiming, amplitude, metrical structure and spectral distribution seem to be available in the structure of low-level auditory descriptors used in the methodology