Visual Research Articles

Selection drives divergence of eye morphology in sympatric Heliconius butterflies.

When populations experience different sensory conditions, natural selection may favor sensory system divergence, affecting peripheral structures and/or downstream neural pathways. We characterized the outer eye morphology of sympatric Heliconius species from different forest types and their first-generation reciprocal hybrids to test for adaptive visual system divergence and hybrid disruption. In Panama, Heliconius cydno occurs in closed forests, whereas Heliconius melpomene resides at the forest edge. Among wild individuals, H. cydno has larger eyes than H. melpomene, and there are heritable, habitat-associated differences in the visual brain structures that exceed neutral divergence expectations. Notably, hybrids have intermediate neural phenotypes, suggesting disruption. To test for similar effects in the visual periphery, we reared both species and their hybrids in common garden conditions. We confirm that H. cydno has larger eyes and provide new evidence that this is driven by selection. Hybrid eye morphology is more H. melpomene-like despite body size being intermediate, contrasting with neural trait intermediacy. Overall, our results suggest that eye morphology differences between H. cydno and H. melpomene are adaptive, and that hybrids may suffer fitness costs due to a mismatch between the peripheral visual structures and previously described neural traits that could affect visual performance.

ADVANCED SHOPLIFTING PREVENTION AND ALERT STSYEM

Detecting human beings accurately in a visual surveillance system is crucial for diverse application areas including abnormal event detection, human gait characterization, congestion analysis, person identification, gender classification and fall detection for elderly people. The first step of the detection process is to detect an object which is in motion. Object detection could be performed using YOLOv7, optical flow and spatio-temporal filtering techniques. Once detected, a moving object could be classified as a human being using shape-based, texture-based or motion-based features. A comprehensive review with comparisons on available techniques for detecting human beings in surveillance videos is presented in this paper. The characteristics of few benchmark datasets as well as the future research directions on human detection have also been discussed. We can use camera for Human Motion Detection. The Camera is used to catch the live images of the area in which it is being implemented, if any object is moving. The captured images are stored for further work. If motion is found in this video, the computer will start recording, buzz an alarm and send SMS to people listed in its database. In this way the system will provide the security against any misdeed. Keywords: YOLOv7, SMS, E-mail, CCTV, SMTP, RFID

Blind Quality Assessment of Dense 3D Point Clouds with Structure Guided Resampling

Objective quality assessment of 3D point clouds is essential for the development of immersive multimedia systems in real-world applications. Despite the success of perceptual quality evaluation for 2D images and videos, blind/no-reference metrics are still scarce for 3D point clouds with large-scale irregularly distributed 3D points. Therefore, in this paper, we propose an objective point cloud quality index with Structure Guided Resampling (SGR) to automatically evaluate the perceptually visual quality of dense 3D point clouds. The proposed SGR is a general-purpose blind quality assessment method without the assistance of any reference information. Specifically, considering that the human visual system (HVS) is highly sensitive to structure information, we first exploit the unique normal vectors of point clouds to execute regional pre-processing which consists of keypoint resampling and local region construction. Then, we extract three groups of quality-related features, including: 1) geometry density features; 2) color naturalness features; 3) angular consistency features. Both the cognitive peculiarities of the human brain and naturalness regularity are involved in the designed quality-aware features that can capture the most vital aspects of distorted 3D point clouds. Extensive experiments on several publicly available subjective point cloud quality databases validate that our proposed SGR can compete with state-of-the-art full-reference, reduced-reference, and no-reference quality assessment algorithms.

Heads-up 3-Dimensional Visualization to Enhance Video Endoscopy During Vitreoretinal Surgery

Purpose: To describe 2 cases in which video endoscopy was combined with heads-up 3-dimensional (3D) visualization. Methods: The imaging modalities of the heads-up 3D visualization system and video endoscopy were combined by converting the endoscope’s S-Video output into a high-definition multimedia interface. The technique was used in 2 cases that included lens dislocation and endophthalmitis. Results: In the 2 cases, the heads-up split-screen view simplified the surgical setup. Simultaneously viewing the endoscopic image and widefield 3D image anecdotally appeared to improve ergonomics, help keep the probe oriented, and assist in guiding surgical movements endoscopically. Conclusions: These cases show the advantages of a heads-up 3D system to simultaneously view endoscopic and widefield images during ophthalmic endoscopy in vitreoretinal surgery.

Uncommon opsin’s retinal isomer is involved in mammalian sperm thermotaxis

In recent years it became apparent that, in mammals, rhodopsin and other opsins, known to act as photosensors in the visual system, are also present in spermatozoa, where they function as highly sensitive thermosensors for thermotaxis. The intriguing question how a well-conserved protein functions as a photosensor in one type of cells and as a thermosensor in another type of cells is unresolved. Since the moiety that confers photosensitivity on opsins is the chromophore retinal, we examined whether retinal is substituted in spermatozoa with a thermosensitive molecule. We found by both functional assays and mass spectrometry that retinal is present in spermatozoa and required for thermotaxis. Thus, starvation of mice for vitamin A (a precursor of retinal) resulted in loss of sperm thermotaxis, without affecting motility and the physiological state of the spermatozoa. Thermotaxis was restored after replenishment of vitamin A. Using reversed-phase ultra-performance liquid chromatography mass spectrometry, we detected the presence of retinal in extracts of mouse and human spermatozoa. By employing UltraPerformance convergence chromatography, we identified a unique retinal isomer in the sperm extracts—tri-cis retinal, different from the photosensitive 11-cis isomer in the visual system. The facts (a) that opsins are thermosensors for sperm thermotaxis, (b) that retinal is essential for thermotaxis, and (c) that tri-cis retinal isomer uniquely resides in spermatozoa and is relatively thermally unstable, suggest that tri-cis retinal is involved in the thermosensing activity of spermatozoa.

Bio-inspired foveal super-resolution method for multi-focal-length images based on local gradient constraints

Most existing super-resolution (SR) imaging systems, inspired by the bionic compound eye, utilize image registration and reconstruction algorithms to overcome the angular resolution limitations of individual imaging systems. This article introduces a multi-aperture multi-focal-length imaging system and a multi-focal-length image super-resolution algorithm, mimicking the foveal imaging of the human eye. Experimental results demonstrate that with the proposed imaging system and an SR imaging algorithm inspired by the human visual system, the proposed method can enhance the spatial resolution of the foveal region by up to 4 × compared to the original acquired image. These findings validate the effectiveness of the proposed imaging system and computational imaging algorithm in enhancing image texture and spatial resolution.

Calibration method for binocular vision system with large field of view based on small target image splicing

In vision measurement, camera calibration has a significant impact on measurement precision. The classical target-based calibration methods require the target to occupy more than one-third of the field of view. A small-size target that does not meet the requirements results in poor calibration accuracy, while an appropriate large-size target is difficult to manufacture and inconvenient to operate. In view of the above problem, we propose a flexible and accurate calibration method based on small target image splicing to calibrate the binocular vision system with a large field of view. The spliced images and virtual large targets are constructed to extend the target size, providing better flexibility for calibration. Moreover, an optimization objective function integrating two constraints in the imaging plane and measurement space is presented to improve the calibration accuracy during the parameter optimization process. The simulation experiments and actual experiments are carried out to test the performance of the proposed method. The results demonstrate that the calibration accuracy of the proposed method using a small target is equivalent to that of Zhang’s method using a large target. Additionally, when using a same-size target, the parameter error of the proposed method is less than that of Zhang’s method, and the proposed method reduces the distance measurement error from 1.169 mm to 0.208 mm compared to Zhang’s method.

A nasal chemosensation–dependent critical window for somatosensory development

Nasal chemosensation is considered the evolutionarily oldest mammalian sense and, together with somatosensation, is crucial for neonatal well-being before auditory and visual pathways start engaging the brain. Using anatomical and functional approaches in mice, we reveal that odor-driven activity propagates to a large part of the cortex during the first postnatal week and enhances whisker-evoked activation of primary whisker somatosensory cortex (wS1). This effect disappears in adult animals, in line with the loss of excitatory connectivity from olfactory cortex to wS1. By performing neonatal odor deprivation, followed by electrophysiological and behavioral work in adult animals, we identify a key transient regulation of nasal chemosensory information necessary for the development of wS1 sensory-driven dynamics and somatosensation. Our work uncovers a cross-modal critical window for nasal chemosensation–dependent somatosensory functional maturation.

Eye development influences horn size but not patterning in horned beetles.

Understanding the origin of novel morphological traits is a long-standing objective in evolutionary developmental biology. We explored the developmental genetic mechanisms that underpin the formation of a textbook example of evolutionary novelties, the cephalic horns of beetles. Previous work has implicated the gene regulatory networks associated with compound eye and ocellar development in horn formation and suggested that horns and compound eyes may influence each other's sizes. Therefore, we investigated the functional significance of genes central to visual system formation in the initiation, patterning, and size determination of head horns across three horned beetle species. We find that while the downregulation of canonical eye patterning genes reliably reduces or eliminates compound eye formation, it does not alter the position or shape of head horns yet does result in an increase in relative horn length. We discuss the implications of our results for our understanding of the genesis of cephalic horns in particular and evolutionary novelties in general.

Semantic scene segmentation for indoor autonomous vision systems: leveraging an enhanced and efficient U-NET architecture

Semantic scene segmentation for indoor autonomous vision systems: leveraging an enhanced and efficient U-NET architecture

Bio‐Inspired Crystalline Core‐Shell Guanine Spherulites

AbstractSpherical particles with diameters within the wavelength of visible light, known as spherulites, manipulate light uniquely due to their spatial organization and their structural birefringence. Most of the known crystalline spherulites are branched, and composed of metals, alloys, and semi‐crystalline polymers. Recently, a different spherulite architecture was discovered in the vision systems of decapod crustaceans ‐ core‐shell spherulites composed of highly birefringent (Δn ∼ 30%) organic single‐crystal platelets, with exceptional optical properties. These metastructures, which efficiently scatter light even in dense aqueous environments, have no synthetic equivalence and serve as a natural proof‐of‐concept as well as synthetic inspiration for thin scattering media. Here, we present the synthesis of core‐shell spherulites composed of guanine crystal platelets (Δn ∼ 25%) in a two‐step emulsification process in which we use a water/oil/water emulsion and induced pH changes to promote interfacial crystallization. Carboxylic acids neutralize the dissolved guanine salts to form spherulites composed of single, radially stacked, β‐guanine platelets, which are oriented tangentially to the spherulite surface. Using Mie theory calculations and forward scattering measurements from single spherulites, we find that due to the single‐crystal properties and orientation, the synthetic spherulites possess a high tangential refractive index, similarly to biogenic particles.This article is protected by copyright. All rights reserved

A Drive Interrupted: Stroke of the Anterior Choroidal Artery – A Case Report

The anterior choroidal artery (AChA) is the most distal branch of the internal carotid artery (ICA) The ACHA is significant because it supplies important structures in the brain, including the optic tract, anterior portion of cerebral peduncle, lateral geniculate body, uncus, globus pallidus, posterior and superficial areas of the thalamus, and the retrolenticular and posterior portions of the internal capsule on the same side as the artery. Isolated strokes involving the AChA are rare and can result in HHH Syndrome, consisting of contralateral hemiplegia, hemisensory loss, and homonymous hemianopia. Features which distinguish an AChA infarction from larger arterial pathology are lack of headache and lack of depressed level of consciousness in subacute infarction, and usually lack of aphasia acutely. The etiology remains controversial, with proposed mechanisms including cardioembolic, large-vessel atherosclerosis, dissection of the ICA, small-vessel occlusion, and cryptogenic causes. Herein, the authors report a case of an isolated AChA infarction resulting in a right-sided, pure motor hemiparesis with no sensory or vision loss, highly suggestive of cardioembolic origin, with the evaluation of the patient, and eventual treatment strategy.

Visual Deficits and Diagnostic and Therapeutic Strategies for Neurofibromatosis Type 1: Bridging Science and Patient-Centered Care

Neurofibromatosis type 1 (NF1) is an inherited autosomal dominant disorder primarily affecting children and adolescents characterized by multisystemic clinical manifestations. Mutations in neurofibromin, the protein encoded by the Nf1 tumor suppressor gene, result in dysregulation of the RAS/MAPK pathway leading to uncontrolled cell growth and migration. Neurofibromin is highly expressed in several cell lineages including melanocytes, glial cells, neurons, and Schwann cells. Individuals with NF1 possess a genetic predisposition to central nervous system neoplasms, particularly gliomas affecting the visual pathway, known as optic pathway gliomas (OPGs). While OPGs are typically asymptomatic and benign, they can induce visual impairment in some patients. This review provides insight into the spectrum and visual outcomes of NF1, current diagnostic techniques and therapeutic interventions, and explores the influence of NF1-OPGS on visual abnormalities. We focus on recent advancements in preclinical animal models to elucidate the underlying mechanisms of NF1 pathology and therapies targeting NF1-OPGs. Overall, our review highlights the involvement of retinal ganglion cell dysfunction and degeneration in NF1 disease, and the need for further research to transform scientific laboratory discoveries to improved patient outcomes.

Oxide Based Pentachromatic‐Vision Inspired Optoelectronic Synaptic Transistor with Large Conduction States Over 512

AbstractOptoelectronic neuromorphic devices based on oxide semiconductors have been potentially investigated to mimic the functions of human visual synapses. However, the challenge comes from the wide bandgap characteristics of numerous oxide semiconductors, which restricts the response range of the device under ultra‐violet (UV) region. Strategies for widening the response range are mostly focused on artificially generating the defect states, however, most of them results in mimicking the tetrachromatic visual system from UV to visible light range. To be used for industries such as robotics, or autonomous vehicles, mimicking the tetrachromatic vision system should be overcome up to near‐infrared (NIR) region. Here, a facile solution processed indium‐gallium‐zinc‐oxide and silver oxide structured optoelectronic synaptic transistor is fabricated not only to mimic the function of human synapses, but to overcome the tetrachromatic human visual system up to the NIR region. The device not only showed photoresponse characteristics under the entire 405 to 830 nm wavelength region, but also showed significant synaptic behaviors with over 512 conduction states under a reasonable incident light power density of 4.5 mW cm−2. The results will offer a useful facile method for fabricating optoelectronic synaptic transistors that can overcome the tetrachromatic vision systems.

Research on load monitoring technology of mine hoist based on machine vision

A hoist load monitoring method based on machine vision technology is proposed in this paper to address the frequent overloading accidents of mine hoists and the low safety and reliability of existing contact load monitoring technologies. The depth image of the skip undergoes time domain and spatial bilateral filtering algorithms for noise reduction, followed by conditional filtering and downsampling algorithms to remove redundant point cloud data. Point cloud recognition, extraction, segmentation, and alignment algorithms are then applied to quickly generate a skip point cloud model. A surface reconstruction optimization process combining greedy projection triangulation algorithm and void repair algorithm is proposed to obtain a smooth and complete sealing of the skip. The closed surface model volume is calculated using VTK volume function. Based on single-rope winding hoist, a load visual monitoring system is constructed for relevant experimental research. Results show that this method can accurately measure the loaded coal volume with a relative error range of 0.05%–4.13%, meeting practical application requirements while providing an effective way for non-contact accurate measurement of hoist loads in mines.

Nighttime Harvesting of OrBot (Orchard RoBot)

The Robotics Vision Lab of Northwest Nazarene University has developed the Orchard Robot (OrBot), which was designed for harvesting fruits. OrBot is composed of a machine vision system to locate fruits on the tree, a robotic manipulator to approach the target fruit, and a gripper to remove the target fruit. Field trials conducted at commercial orchards for apples and peaches during the harvesting season of 2021 yielded a harvesting success rate of about 85% and had an average harvesting cycle time of 12 s. Building upon this success, the goal of this study is to evaluate the performance of OrBot during nighttime harvesting. The idea is to have OrBot harvest at night, and then human pickers continue the harvesting operation during the day. This human and robot collaboration will leverage the labor shortage issue with a relatively slower robot working at night. The specific objectives are to determine the artificial lighting parameters suitable for nighttime harvesting and to evaluate the harvesting viability of OrBot during the night. LED lighting was selected as the source for artificial illumination with a color temperature of 5600 K and 10% intensity. This combination resulted in images with the lowest noise. OrBot was tested in a commercial orchard using twenty Pink Lady apple trees. Results showed an increased success rate during the night, with OrBot gaining 94% compared to 88% during the daytime operations.

Impact of early physiotherapy intervention in managing homonymous hemianopia due to posterior cerebral artery infarct—a case report

Homonymous hemianopia field loss can develop as a result of injury to any part of the retro chiasmal visual pathway and is frequently fatal for subjects. The most common cause of homonymous hemianopia in older persons is ischemic infarction of the occipital lobe and its causes are multifactorial, frequently providing a diagnostic challenge to the clinician and signaling the necessity for a thorough systemic health review. Hemianopia is a loss of half of the visual field in each eye in which the inner or nasal half of one eye and the outer or temporal half of the other eye is affected. We report a case of a 72-year-old male subject who visited our department with complaints of weakness on the right side with difficulty seeing on the right side for 3 days. After undergoing various investigations, it was found that there is an acute infarct in the posterior cerebral artery territory supplying the left medial temporal lobe, medial occipital lobe, left thalamus, and splenium of the corpus callosum. After a physiotherapeutic examination provisionally, he was diagnosed with right hemiparesis and homonymous hemianopia, and thus, we administered an early physical therapy intervention which was found to be effective.

(What's the story) morning glory? MRI findings in morning glory disc anomaly.

Morning glory disc anomaly (MGDA) is a rare congenital ophthalmologic disorder. Historically it has been diagnosed fundoscopically, with little in the literature regarding its imaging findings. The purpose of this study is to further characterize the orbital and associated intracranial magnetic resonance imaging (MRI) findings of MGDA in our tertiary pediatric center. A retrospective review was performed of fundoscopically-diagnosed cases of MGDA, that had been referred for MRI. All MRI studies were scrutinized for orbital and other intracranial abnormalities known to occur in association with MGDA. 18 of 19 cases of MGDA showed three characteristic MRI findings: funnel-shaped morphology of the posterior optic disc, abnormal soft tissue associated with the retrobulbar optic nerve, and effacement of adjacent subarachnoid spaces. The ipsilateral (intraorbital) optic nerve was larger in one patient and smaller in six. The ipsilateral optic chiasm was larger in two patients and smaller in one. This study represents a comprehensive radiological-led investigation into MGDA. It describes the most frequently-encountered MRI findings in MGDA and emphasizes the importance of MRI in this cohort, i.e., in distinguishing MGDA from other posterior globe abnormalities, in assessing the visual pathway, and in screening for associated intracranial abnormalities - skull base/cerebral, vascular, and facial. It hypothesizes neurocristopathy as an underlying cause of MGDA and its associations. Caliber abnormalities of the ipsilateral optic nerve and chiasm are a frequent finding in MGDA. Optic pathway enlargement should not be labeled "glioma". (239/250).

A low-cost vision system for online reciprocal collision avoidance with UAVs

In this article, we propose a reciprocal collision avoidance system for autonomous drones, based on computer vision and using relative positioning in an indoor environment. This dynamic environment represents a demanding challenge, but it is crucial for any future existence of multiple drones operating in urban areas. We use commercial AR Drone 2.0 robots, which represent that our proposal is suitable for low-cost equipment. In our case, we attempt to achieve the collision avoidance of two drones that fly one towards the other and react online autonomously to signals received by their computer vision systems with a decentralized control strategy. We test this in four different experiments with demanding conditions. For this purpose, we get the camera signal of the onboard drones and tune their behavior to react smoothly and precisely. We report encouraging positive results and provide the code we use in the experiments for replication.

Effect of visual feedback balance system combined with digital treadmill on gait kinematics in patients with subacute cerebral infarction.

Effect of visual feedback balance system combined with digital treadmill on gait kinematics in patients with subacute cerebral infarction.