Pinna Shape Research Articles

Deep Learning‐Driven Modeling of Dynamic Acoustic Sensing in Biomimetic Soft‐Robotic Pinnae

ABSTRACTBiological function often depends on complex mechanisms of a dynamic, time‐variant nature. An example is certain bat species (horseshoe bats—Rhinolophidae) that use intricate pinna musculatures to execute a variety of pinna deformations. While prior work has indicated the potential significance of these motions for sensory information encoding, it remains unclear how the complex time‐variant pinna geometries could be controlled to enhance sensory performance. To address this issue, this work has investigated deep neural network models as digital twins for biomimetic pinnae. The networks were trained to predict the acoustic impacts of the deformed pinna geometries. A total of three network architectures have been evaluated for this purpose using physical numerical simulations (boundary element method) as ground truth. The networks predicted the acoustic beampattern function from pinna shape or even directly from the states of actuators that were used to deform the pinna shapes in simulation. Inserting prior knowledge in the form of beam‐shaped basis functions did not improve network performance. The ability of the networks to produce beampattern predictions with low computational effort (in about three milliseconds each) should lend itself readily to supporting learning methods such as deep reinforcement learning that require many such functional evaluations.

Investigating the impact of biomimetic pinna shape variations on clutter echoes received from natural environments

Bat species navigating dense vegetation based on biosonar have to obtain the necessary sensory information from “clutter echoes”, i.e., echoes that are superpositions of contributions from many reflecting facets (e.g., leaves) and hence have highly unpredictable waveforms. Prior results have suggested that pinna motions could aid in direction-finding tasks based on deterministic echo patterns. This raises the question whether varying pinna shapes could also have a function significance for challenging biosonar tasks performed on clutter echoes. As a first, task-independent step to test this hypothesis it has been investigated whether different pinna shapes have a consistent effect on clutter echoes despite the random nature of these signals. This was accomplished using a dedicated laboratory setup that produced large amounts of uncorrelated clutter echo data by agitating an artificial foliage with fans between echoes. Deep learning methods were then applied to identify the pinna shape that received a given clutter echo. A two-dimensional convolutional neural network operating on spectrograms achieved 90% validation accuracy in this task. This finding demonstrates that even small pinna deformations can impart consistent effects on the clutter echoes. Ongoing research is directed at analyzing the nature of the signal properties that the successful classifications were based on.

Analysis of laser scanning and photogrammetric scanning accuracy on the numerical determination of Head-Related Transfer Functions of a dummy head

Individual Head-Related Transfer Functions (HRTFs) are necessary for the accurate rendering of virtual scenes. However, their acquisition is challenging given the complex pinna shape. Numerical methods can be leveraged to compute HRTFs on meshes originating from precise scans of a subject. Although photogrammetry can be used for the scanning, its inaccuracy might affect the spatial cues of simulated HRTFs. This paper aims to assess the significance of the photogrammetric error affecting a Neumann KU100 dummy head scan. The geometrical differences between the photogrammetric scan and a laser scan are mainly located at the pinna cavities. The computed photogrammetric HRTFs, compared to measured and simulated data using objective and perceptually inspired metrics, show deviation in high frequency spectral features, stemming from the photogrammetric scanning error. This spectral deviation hinders the modelled elevation perception with photogrammetric HRTFs to levels comparable to renderings with nonindividual data. Extracting the photogrammetric geometry at individual ear cavities and merging it to the laser mesh, an assessment of the influence of the inaccuracy at different pinna structures is conducted. Correlation analysis between acoustic and geometrical metrics computed on the results is used to identify the most relevant geometrical metrics in relation to the HRTFs.

The micro‐morphological characteristics of Cyrtomium Presl (Dryopteridaceae) from Shandong, China and their taxonomic significance

The fern genus Cyrtomium is generally recognized as a genus difficult to identify taxonomically. Here, the micro‐morphological characteristics of nine species and one cultivar of Cyrtomium from Shandong Province of China were studied using scanning electron microscopy (SEM): C. confertiserratum, C. falcatum, C. fortunei, C. polypterum, C. reflexosquamatum, C. semifertile, C. shandongensis, C. tukusicola, C. yamamotoi and C. yamamotoi var. intermedium. The morphology of the pinna margin, upper and lower epidermis, indusia, shape of pinnae, sori distribution and spore morphology were carefully examined and photographed under SEM. The results showed that the micro‐morphological characteristics of the pinna margin, upper and lower epidermis, indusia and spore morphology were stable within species and show significant differences between interspecies. The results provide not only important scientific evidence for the micro‐morphological classification and identification of Cyrtomium, but also an important scientific basis for the development and utilization of this genus for medicine use and the protection of germplasm resources.

Athyrium aberrans (Athyriaceae), a new species of the lady ferns from southeastern Xizang, China, based on morphological and molecular evidence

A new fern species, Athyrium aberrans (Athyriaceae), currently only known from southeastern Xizang, China is described. Morphologically, A. aberrans is superficially similar to A. falcatum in the habit and pinna shape, but the new species can easily be distinguished from the latter by having purplish petioles and rachises, a bulbil on the rachis below the lamina apex, and finely toothed pinna margins. A phylogenetic analysis based on five plastid markers demonstrates that A. aberrans is most closely related to but obviously distinct from A. epirachis.

<p align="left"><strong><em>Polystichum dongchuanense</em> and <em>P. menglaense</em> (subg. <em>Haplopolystichum</em>; Dryopteridaceae), two new ferns from Yunnan, China</strong></p>

Two new fern species, Polystichum dongchuanense and P. menglaense (Dryopteridaceae), are described and illustrated from Yunnan, China. Both are members of P. subg. Haplopolystichum sect. Haplopolystichum. Polystichum dongchuanense is most similar to P. acutidens in plant size and pinna size, but the two can be distinguished from each other by pinna serration and soral number on pinnae. Polystichum menglaense is most similar to P. deltodon in plant size, but the two are different in pinna shape and soral distribution. Both new species have extremely narrow distributions and are classified as Critically Endangered (CR) following IUCN Red List Criteria.

Serpocaulon orosiense, a New Hybrid of Serpocaulon (Polypodiaceae) from Costa Rica

Four hybrids between Serpocaulon species have been described, one of them S. × sessilipinnum was the only known hybrid between two different clades proposed by Smith et al. In this work, a new hybrid S. × orosiense is described, being the second known hybrid between clades: 1) Serpocaulon loriceum and 2) S. fraxinifolium. The detailed study of the intermediate morphology of the characters of the new taxon and their progenitors were made by light microscopy with a Motic Instruments brand binocular stereoscope, Model SMZ-171-BLED and photographs of the spores with a Motic brand binocular microscope, model BA210E. The new nothotaxon has intermediate characters between S. fraxinifolium and S. loriceum as size of the frond; shape, division and apex of the leaf blade; shape, broad, apex and number of pinnae; and number of series of areoles and sori. As result and conclusion, a new nothotaxon with intermediate morphology between two progenitors is discovered between different clades within the genus Serpocaulon.

External Ear Features: Role in Tracing Inheritance

Background: The external ear is unique in shape, size and orientation. It has symmetry and asymmetry among generations. Its morphological variation helps to trace genetic inheritance. The objective of this study was to identify this morphological variation among parents and siblings.
 Methods: The study was conducted in Manipal colleges of medical sciences. Images were procured from 147 families. The morphological character of external ears including, shape of pinnae, concha, tragus, ear lobule and attachment of lobule to cheek were matched among Parents and offspring.
 Results: This study included 882 pinnae in 147 families. Total 4410 morphological characteristics have been analyzed. Tragus was the most common matching character between parents and offspring Kappa measuring coefficient was statistically significant for shape of pinna, concha, ear lobule, ear lobule attachment to cheek.
 Conclusions: The most of external ear morphology matches between parents and offspring which may be a helpful tool in tracing hereditary inheritance.

An emended and amplified description of Pecopteris apicalis Knight, a fern morphospecies of mid-Stephanian age from NW Spain

Extensive adpression material of the fern morphospecies Pectopteris apicalis Knight has been collected from overburden from opencast mining in the Paragido-Vallejo area oh the Barruelo Coalfield, close to the collection site of the holotype of the species. This has permitted a more detailed description of the key characteristics than was previously possible and an emended diagnosis. The large frond fragments demonstrate large pinnae of antepenultimate order, length in excess of 0.4 m, with apparent attachment to a very robust petiole in a tripinnate frond structure. Other diagnostic features of the species confirmed in this wide range of material cover the dimensions, acuminate shape, and terminal of last order pinnae, the range of dimensions and shape of pinnules and the characteristic consistently bifurcate venation. Fertile organs have been identified only on one specimen collected from another opencast working in the Barruelo Coalfield, at a lower level in the same stratigraphic unit. Although indistinct, the fertile organs comprise two rows of small circular sori on either side of the mid-vein, reminiscent of the genus Asterotheca, although the material does not permit reliable identification. Discussion of the possible systematic relationship of this species suggests the closet affiliation is with the cyatheoid group of pecopterid marattialean species. The Peragido-Vallejo material occurs within a low diversity flora which has undergone minimal transport from its site of growth, interpreted as in an interdistributary back-swamp area on a near-coastal alluvial plain

Bat-inspired dynamic features and factors that modulate their impact on speech recognition

One of the most serious remaining challenges in speech recognition is dealing with corruption of speech signal by other nuisance speech (babble). A promising approach to solving the problem of separating the signal of interest from the detractors is to inject direction dependent signatures into all signals received, which has been realized by bat-inspired biomimetic pinna—dynamic periphery. Changing the shape of a biomimetic pinna during the recordings introduces substantial time-variant signatures into speech signals. To investigate the utility of these signatures, we have used bioinspired signal representations (cochleagram and spikegram) as input for speech classifiers based on Gaussian mixture models (GMM) and hidden Markov models (HMM). The speech samples used were obtained from open source databases: spoken digits and alphabets from Carnegie Mellon University were mixed with babble or noise samples from Columbia University. Since the time-variant signatures were found to depend strongly on the direction of the sound source, we attempted to include datasets from different directions for training and testing to feed into the classifiers. The results indicate that dynamic periphery can substantially improve recognition and that these effects depend on the signal representation as well as the angular composition of the training dataset.One of the most serious remaining challenges in speech recognition is dealing with corruption of speech signal by other nuisance speech (babble). A promising approach to solving the problem of separating the signal of interest from the detractors is to inject direction dependent signatures into all signals received, which has been realized by bat-inspired biomimetic pinna—dynamic periphery. Changing the shape of a biomimetic pinna during the recordings introduces substantial time-variant signatures into speech signals. To investigate the utility of these signatures, we have used bioinspired signal representations (cochleagram and spikegram) as input for speech classifiers based on Gaussian mixture models (GMM) and hidden Markov models (HMM). The speech samples used were obtained from open source databases: spoken digits and alphabets from Carnegie Mellon University were mixed with babble or noise samples from Columbia University. Since the time-variant signatures were found to depend strongly on the dir...

Characterization of pinna motion patterns in hipposiderid bats

Hipposiderid bats have a set of highly differentiated pinna muscles that support different pinna motion patterns during biosonar behaviors. It has been shown that these bats' pinna motions fall into two separate categories: Rigid motions that change only pinna orientation and non-rigid motions that also change pinna shape. It remains unclear if further subdivisions of these two categories (e.g., different orientations for rigid motions and different deformation patterns for non-rigid motions) can be made. In order to investigate this question, experiments have been conducted where the positions of a dense set of landmark points (50–80 per pinna) were reconstructed based on footage from an array of four high-speed video cameras. The resulting point trajectory data (positions as a function of time) was clustered to facilitate the detection of patterns. Clustering revealed a structure of coherent surface patches for rigid as well as non-rigid motion. For the rigid motion pilot data set, these patches followe...

Intrafamilial Pinna Shape Variations of Fern Species Under Family Thelypteridaceae and Nephrolepidaceae Using Elliptic Fourier Analysis

Fern species under family Thelypteridaceae and Nephrolepidaceae tend to have similarities when it comes to leaf morphology. Due to their cohesive morphological appearance, species under these two families are hard to distinguish from the other. While qualitative descriptions in leaf shape could aid in understanding the identification, evolution and development of ferns, it is argued that the quantitative description of the shape of the pinna is a good measure in the classification of ferns by delineating species. This study was therefore conducted to quantitatively describe the pinna shape of five species of ferns under family Thelypteridaceae and four species under family Nephrolepidaeceae by Elliptic Fourier Analysis (EFA). Significant shape variations were observed within and between species specifically in width, apex and base of the pinna. Species found on shaded habitat were observed to have broader pinna lamina compared to elongated and narrow pinna of fern species found on open areas. Light availability is argued to possibly influenced the pinna shapes of the ferns. Results of this study have shown the importance of EFA in the quantitative description of biological shape that aid in understanding the relationships of the fern species.

Variasi Morfologi Pteris Vittata l. (Pteridaceae; Pteridophyta) dan Korelasinya dengan Ketinggian Lokasi Tempat Tumbuhnya di Jawa

Pteris vittata has a high morphological variation and it has wide geographic regions around the world . Study of morphology and its correlation with with altitude of plant origin area in Java is very little informed. This aims of this research were first to study the diversity of morphological characters of P. vittata from Java; and to know the correlations among morphological characters to the plant orignated altitute; This study was conducted from September 2012 until September 2013. Plants materials were collected by exploration method. Morphological observations carried out on 130 individuals that had been collected from West Java, Central of Java and Yogyakarta in various altitude areas. Pteris vittata from Java Island varied in the morphological characters. The varied in the morphological characters i.e. size and shape of fronds, pinnae and apical segment. Variations in morphology was not correlated with altitude of plant origin area. Taxonomycally, P. vittata in Java can be divided into two groups infraspecies, namely P.vittata subspecies vittata and P.vittata subspecies emodi.

Head-related transfer function personalization based on spectral notch estimation with stereo images of pinna

Three-dimensional (3-D) sound field reproduction systems such as surround sound reproduction systems are rapidly being developed in recent few years. However, these systems need a lot of space for the placement of loudspeakers. For this reason, a binaural system has been studied as one of the systems, which controls the sound image localization with the head-related transfer functions (HRTFs) and just by using only a headphones. However, the individual differences in body features would cause the variations of HRTFs which greatly affect the direction perception. For this reason, a method based on the spectral notch estimation from the pinna shape has been studied for the personalization of HRTFs. In this study, we propose a new method, in which the depth information used for the spectral notch estimation is measured with stereo images of the pinna. Two cameras are utilized together as a stereo camera to take the disparate stereo images so that we can use the disparity of them to measure the depth information of the pinna. As a result of an evaluation experiment, we could reduce the cost of actual measurement and the burden to the subjects by the proposed method.

A reappraisal of Pecopteris miltonii (Artis) Brongniart, a mid-Westphalian (Early–Mid Pennsylvanian) fern

Pecopteris miltonii , a middle Westphalian fern originally described from Yorkshire, England, is redescribed and figured here from roof shales of the Barnsley Seam, the level from which it was first recorded. This material is regarded as complementary to the holotype, a fertile specimen showing limited morphological variation and almost lacking venation. Pinna shape of the holotype, including terminals, and the shape and dimensions of pinnules, match that of the material in hand. An analysis of the literature shows that only a limited number of specimens recorded with the miltonii epithet may be regarded as properly assigned. This includes a magnificent specimen figured from Lower Silesia by Stur. Although the species is apparently rare, it is fairly widespread, from North America to central Europe (Bohemia, Lower Silesia). The taxonomic position of Pecopteris miltonii is discussed with reference to the genera Lobatopteris and Crenulopteris , and its synonymy with Pecopteris aspidioides is proposed. A full analysis of Pecopteris miltonii and its synonymy serves to delimit this classical species, which has been often misidentified.

An investigation of matching symmetry in the human pinnae with possible implications for 3D ear recognition and sound localization.

The human external ears, or pinnae, have an intriguing shape and, like most parts of the human external body, bilateral symmetry is observed between left and right. It is a well-known part of our auditory sensory system and mediates the spatial localization of incoming sounds in 3D from monaural cues due to its shape-specific filtering as well as binaural cues due to the paired bilateral locations of the left and right ears. Another less broadly appreciated aspect of the human pinna shape is its uniqueness from one individual to another, which is on the level of what is seen in fingerprints and facial features. This makes pinnae very useful in human identification, which is of great interest in biometrics and forensics. Anatomically, the type of symmetry observed is known as matching symmetry, with structures present as separate mirror copies on both sides of the body, and in this work we report the first such investigation of the human pinna in 3D. Within the framework of geometric morphometrics, we started by partitioning ear shape, represented in a spatially dense way, into patterns of symmetry and asymmetry, following a two-factor anova design. Matching symmetry was measured in all substructures of the pinna anatomy. However, substructures that 'stick out' such as the helix, tragus, and lobule also contained a fair degree of asymmetry. In contrast, substructures such as the conchae, antitragus, and antihelix expressed relatively stronger degrees of symmetric variation in relation to their levels of asymmetry. Insights gained from this study were injected into an accompanying identification setup exploiting matching symmetry where improved performance is demonstrated. Finally, possible implications of the results in the context of ear recognition as well as sound localization are discussed.

In Vivo Needle-Based Electromechanical Reshaping of Pinnae

Electromechanical reshaping (EMR) is a low-cost, needle-based, and simple means to shape cartilage tissue without the use of scalpels, sutures, or heat that can potentially be used in an outpatient setting to perform otoplasty. To demonstrate that EMR can alter the shape of intact pinnae in an in vivo animal model and to show that the amount of shape change and the limited cell injury are proportional to the dosimetry. In an academic research setting, intact ears of 18 New Zealand white rabbits underwent EMR using 6 different dosimetry parameters (4 V for 5 minutes, 4 V for 4 minutes, 5 V for 3 minutes, 5 V for 4 minutes, 6 V for 2 minutes, and 6 V for 3 minutes). A custom acrylic jig with 2 rows of platinum needle electrodes was used to bend ears at the middle of the pinna and to perform EMR. Treatment was repeated twice per pinna, in proximal and distal locations. Control pinnae were not subjected to current application when being bent and perforated within the jig. Pinnae were splinted for 3 months along the region of the bend using soft silicon sheeting and a cotton bolster. The ears were harvested the day after splints were removed and before euthanasia. Photographs of ears were obtained, and bend angles were measured. Tissue was sectioned for histologic examination and confocal microscopy to assess changes to microscopic structure and cellular viability. Treated pinnae were bent more and retained shape better than control pinnae. The mean (SD) bend angles in the 7 dosimetry groups were 55° (35°) for the control, 60° (15°) for 4 V for 4 minutes, 118° (15°) for 4 V for 5 minutes, 88° (26°) for 5 V for 3 minutes, 80° (17°) for 5 V for 4 minutes, 117° (21°) for 6 V for 2 minutes, and 125° (18°) for 6 V for 3 minutes. Shape change was proportional to electrical charge transfer, which increased with voltage and application time. Hematoxylin-eosin staining of the pinnae identified localized areas of cell injury and fibrosis in the cartilage and in the surrounding soft tissue where the needle electrodes were inserted. This circumferential zone of injury (range, 1.5-2.5 mm) corresponded to dead cells on cell viability assay, and the diameter of this region increased with total electrical charge transfer to a maximum of 2.5 mm at 6 V for 3 minutes. Electromechanical reshaping produced shape change in intact pinnae of rabbits in this expanded in vivo study. A short application of 4 to 6 V can achieve adequate reshaping of the pinnae. Tissue injury around the electrodes increases with the amount of total current transferred into the tissue and is modest in spatial distribution. This study is a critical step toward evaluation of EMR in clinical trials. NA.

A New Hybrid ofSerpocaulon(Polypodiaceae) from Costa Rica

A new hybrid Serpocaulon × sessilipinnum A. Rojas & J.M. Chaves is described. The new taxon has characters intermediate between S. fraxinifolium (Jacq.) A.R. Sm. and S. ptilorhizon (Christ) A.R. Sm., which are related mainly with leaf size, rhizome scales, shape and division of blade, shape and width of pinnae, number of areolae and sori series, and shape and color of spores.

Identification of sound-localization cues in the HRTF of the bat-head model

Animals such as bats and dolphins exhibit impressive echolocation abilities in terms of ranging, resolution and imaging and therefore represent a valuable learning model for the study of spatial hearing and sound source localization leading to a better understanding of the hearing mechanism and further improvement of the existing localization strategies. This study aims to examine and understand the directional characteristics of a sonar receiver modeled upon the bat auditory system via measurements of the head-related transfer function (HRTF) in the horizontal plane. Four different models of the bat head were considered here and used to evaluate acoustic spectral characteristics of the sound received by the bat's ears – a sphere model, a sphere model with a pinna attached (two pinnae of different size were used in this study) and a bat-head cast. The performed HRTF measurements of the bat-head models were further analyzed and compared to identify monaural spectral localization cues in the horizontal plane defined by the bat's head and pinna shape and size. Our study suggests that the acoustical characteristics of a bio-inspired sonar head measured and specified in advance can potentially improve the performance of a receiver. Moreover, the generated auditory models may hold clues for the design of receiver characteristics in ultrasound imaging and navigation systems.

Reception beamforming in horseshoe bats is a dynamic process

Horseshoe bats execute conspicuous pinna movements as part of their biosonar behaviors. These movements contain rigid rotations as well as deformation components that can result in considerable changes to the pinna shapes. Since pinna shape determines the biosonar system's sensitivity as a function of direction and frequency, these non-rigid deformations could be functionally relevant. In the work reported here, it has been investigated how the non-rigid deformations of pinna shape relate to the arrival of echoes. For this purpose, multi-camera high-speed video recordings of both pinna of a bat were synchronized with ultrasonic recordings of the emitted pulses and the returning echoes from a microphone placed next to the head of the animals. Landmark dots were painted on the pinna to enhance the determination of position and velocity from stereo pairs of video recordings. It was found that the pinnae were deformed between as well as during echo receptions. Hence, the echoes were received by different static each pinna shapes (e.g., bent or upright) as well as by pinna shapes that underwent non-rigid deformation within the duration of the echo. As a consequence, echo reception by horseshoe bats involves dynamic beampatterns that can change between as well as during echoes.