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Identifying three-dimensional signals (e.g. faces) can be challenging because the signals appear different when seen from different viewpoints. One simple solution is to always view signals from a particular viewpoint. A more flexible but also more cognitively challenging solution is viewpoint-independent recognition, where receivers can identify signals from multiple viewing angles. Here, we use same/different concept learning to test viewpoint-independent recognition for conspecific and heterospecific faces in two species ofPolistespaper wasps that have three-dimensional visual signals.P. fuscatususe conspecific facial patterns for individual recognition, whileP. dominulause conspecific facial patterns as a signal of fighting ability. Previous work has shown thatP. fuscatusare able to identify novel viewpoints of conspecific faces through extrapolation. Here, we show thatP. fuscatusandP. dominuladiffer in their capacity for viewpoint-independent recognition.P. fuscatusexhibit viewpoint-independent recognition for bothP. fuscatusandP. dominulafaces. In contrast,P. dominulado not have viewpoint-independent recognition for conspecific or heterospecific faces. These results suggest that viewpoint-independent recognition through extrapolation may be an adaptive strategy to facilitate individual face recognition across a wide range of taxa.
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Generic fabrication solution of freeform Fresnel optics using ultra-precision turning
Freeform Fresnel optics represent an emerging category of modern optics that reproduces powerful optical functionalities while maintaining an ultra-compact volume. The existing ultra-precision machining (UPM) technique faces technical challenges in meeting the fabrication requirements for freeform Fresnel optics because of the absence of appropriate geometry definition and corresponding tool path planning strategy to overcome the extreme asymmetry and discontinuity. This study proposes a new scheme for ultra-precision machining using four axes (X,Y,Z,C) to fabricate freeform Fresnel optics, including a general geometry description for freeform Fresnel optics, the quasi-spiral tool path generation strategy to overcome the lack of rotary symmetry, and the adaptive tool pose manipulation method for avoiding tool interference. In addition, the tool edge compensation and the adaptive timestep determination are also introduced to enhance the performance and efficiency of the proposed scheme. The machining of two exemplary freeform Fresnel lenses is successfully demonstrated. Overall, this study introduces a comprehensive routine for the fabrication of freeform Fresnel optics and proposes the adaptive tool pose manipulation scheme, which has the potential for broader applications in the ultra-precision machining of complex or discontinuous surfaces.
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- Award ID(s):
- 2229170
- PAR ID:
- 10544523
- Publisher / Repository:
- Optica
- Date Published:
- Journal Name:
- Optics Express
- Volume:
- 31
- Issue:
- 26
- ISSN:
- 1094-4087
- Page Range / eLocation ID:
- 44622
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1364/OE.509238
