Object symmetry is a visual attribute that may contribute to perceptual judgement and to action. We evaluated the effects of varying the physical symmetry of planar objects (presence versus absence) on both aspects. In Experiment 1, subjects estimated the magnitude of visually perceived symmetry of the objects. The results confirmed the influence of physical symmetry on perceived symmetry, and supported our binary categorisation of stimulus objects in terms of presence versus absence of physical symmetry. In Experiment 2, participants used a precision grip to grasp and stably lift the same planar objects varying in degree of symmetry. Choice of grasp points was unrestricted. Participants selected a grasp axis (between thumb and middle finger) that limited the perpendicular distance from CM (i.e., grasp-axis error) to just a few millimetres. Moreover, they took advantage of visual cues to object symmetry to better determine CM, thus reducing their grasp-axis error for symmetric (vs. asymmetric) objects by 31%. We interpret these findings in terms of user and object-geometry constraints on grasp-point selection.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1007/s00221-003-1522-5 | DOI Listing |
iScience
January 2025
Division of Optometry, Health Sciences, City University of London, London EC1V 0HB, UK.
A key property of our environment is the mirror symmetry of many objects, although symmetry is an abstract global property with no definable shape template, making symmetry identification a challenge for standard template-matching algorithms. We therefore ask whether Deep Neural Networks (DNNs) trained on typical natural environmental images develop a selectivity for symmetry similar to that of the human brain. We tested a DNN trained on such typical natural images with object-free random-dot images of 1, 2, and 4 symmetry axes.
View Article and Find Full Text PDFVis Neurosci
December 2024
Department of Psychology, University of Stirling, Stirling, FK9 4LA, Scotland, United Kingdom.
Symmetry is a salient visual feature in the natural world, yet the perception of symmetry may be influenced by how natural lighting conditions (e.g., shading) fall on the object relative to its symmetry axis.
View Article and Find Full Text PDFBiol Methods Protoc
November 2024
Department of Computer Science & Niels Bohr Institute, University of Copenhagen, Copenhagen, 2100, Denmark.
Instance segmentation is the task of assigning unique identifiers to individual objects in images. Solving this task requires breaking the inherent symmetry that semantically similar objects must result in distinct outputs. Deep learning algorithms bypass this break-of-symmetry by training specialized predictors or by utilizing intermediate label representations.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Department of Chemistry, Ohio State University, Columbus, Ohio 43210, USA.
The open-source Python package, MRSimulator, is presented as a simple-to-use, fast, versatile, and extendable package capable of simulating one- and higher-dimensional Nuclear Magnetic Resonance (NMR) spectra under static, magic-angle, and variable-angle conditions. High benchmarks in spectral simulations are achieved by assuming that there are no degeneracies in the energy eigenstates, i.e.
View Article and Find Full Text PDFEntropy (Basel)
November 2024
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
We highlight camphene-camphor-polypropylene plastic as a useful material for self-propelled objects that show aggregation while floating on a water surface. We consider self-propelled rods as an example of aggregation of objects characterized by non-trivial individual shapes with low-symmetry interactions between them. The motion of rods made of the camphene-camphor-polypropylene plastic is supported by dissipation of the surface-active molecules.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!