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Hongjun Choi, Mingi Kim, Onseok Lee
Animal tracking is an important tool for observing behavior, which is useful in various research areas. Animal specimens can be tracked using dynamic models and observation models that require several types of data. Tracking mouse has several barriers due to the physical characteristics of the mouse, their unpredictable movement, and cluttered environments. Therefore, we propose a reliable method that uses a detection stage and a tracking stage to successfully track mouse. The detection stage detects the surface area of the mouse skin, and the tracking stage implements an extended Kalman filter to estimate the state variables of a nonlinear model...
May 19, 2018: Medical & Biological Engineering & Computing
Tigran Petrosyan, Maria Theodorou, Jeff Bamber, Martin Frenz, Michael Jaeger
Epi-style optoacoustic (OA) imaging provides flexibility by integrating the irradiation optics and ultrasound receiver, yet clutter generated by optical absorption near the probe obscures deep OA sources. Localised vibration tagging (LOVIT) retrieves OA signal from images that are acquired with and without a preceding ultrasonic pushing beam: Radiation force leads to a phase shift of signals coming from the focal area resulting in their visibility in a difference image, whereas clutter from outside the pushing beam is eliminated...
June 2018: Photoacoustics
Michael J Arcaro, Lore Thaler, Derek J Quinlan, Simona Monaco, Sarah Khan, Kenneth F Valyear, Rainer Goebel, Gordon N Dutton, Melvyn A Goodale, Sabine Kastner, Jody C Culham
Patients with injury to early visual cortex or its inputs can display the Riddoch phenomenon: preserved awareness for moving but not stationary stimuli. We provide a detailed case report of a patient with the Riddoch phenomenon, MC. MC has extensive bilateral lesions to occipitotemporal cortex that include most early visual cortex and complete blindness in visual field perimetry testing with static targets. Nevertheless, she shows a remarkably robust preserved ability to perceive motion, enabling her to navigate through cluttered environments and perform actions like catching moving balls...
May 9, 2018: Neuropsychologia
Dzmitry A Kaliukhovich, Hans P Op de Beeck
Similar to primates, visual cortex in rodents appears to be organized in two distinct hierarchical streams. Yet there is still little known about how visual information is processed along those streams in rodents. Here we examined how repetition suppression, position and clutter tolerance of the neuronal representations evolve along the putative ventral visual stream in rats. To address this question, we recorded multi-unit spiking activity in primary visual cortex and the more downstream visual laterointermediate (LI) area of head-restrained Long Evans rats...
May 9, 2018: Journal of Neurophysiology
Junseob Shin, Yu Chen, Harshawn Malhi, Frank Chen, Jesse Yen
Degradation of image contrast caused by phase aberration, off-axis clutter, and reverberation clutter remains one of the most important problems in abdominal ultrasound imaging. Multiphase apodization with cross-correlation (MPAX) is a novel beamforming technique that enhances ultrasound image contrast by adaptively suppressing unwanted acoustic clutter. MPAX employs multiple pairs of complementary sinusoidal phase apodizations to intentionally introduce grating lobes that can be used to derive a weighting matrix, which mostly preserves the on-axis signals from tissue but reduces acoustic clutter contributions when multiplied with the beamformed radio-frequency (RF) signals...
May 1, 2018: Ultrasonic Imaging
Bronisław Stec, Waldemar Susek
Determination of the signal power-to-noise power ratio on the input and output of reception systems is essential to the estimation of their quality and signal reception capability. This issue is especially important in the case when both signal and noise have the same characteristic as Gaussian white noise. This article considers the problem of how a signal-to-noise ratio is changed as a result of signal processing in the correlation receiver of a noise radar in order to determine the ability to detect weak features in the presence of strong clutter-type interference...
May 6, 2018: Sensors
Joohyun Seo, Sabino J Pietrangelo, Charles G Sodini, Hae-Seung Lee
This paper details unfocused imaging using single-element ultrasound transducers for motion tolerant arterial blood pressure (ABP) waveform estimation. The ABP waveform is estimated based on pulse wave velocity and arterial pulsation through Doppler and M-mode ultrasound. This paper discusses approaches to mitigate the effect of increased clutter due to unfocused imaging on blood flow and diameter waveform estimation. An intensity reduction model (IRM) estimator is described to track the change of diameter, which outperforms a complex cross-correlation model (C3M) estimator in low contrast environments...
May 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Yucel Karabiyik, Ingvild Kinn Ekroll, Sturla H Eik-Nes, Lasse Lovstakken
Interleaved acquisitions used in conventional triplex mode result in a tradeoff between the frame rate and the quality of velocity estimates. On the other hand, workflow becomes inefficient when the user has to switch between different modes, and measurement variability is increased. This paper investigates the use of power spectral Capon estimator in quantitative Doppler analysis using data acquired with conventional color flow imaging (CFI) schemes. To preserve the number of samples used for velocity estimation, only spatial averaging was utilized, and clutter rejection was performed after spectral estimation...
May 2018: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Fei Guo, Yuan Yang, Yong Gao
Visual prosthesis applying electrical stimulation to restore visual function for the blind has promising prospects. However, due to the low resolution, limited visual field, and the low dynamic range of the visual perception, huge loss of information occurred when presenting daily scenes. The ability of object recognition in real-life scenarios is severely restricted for prosthetic users. To overcome the limitations, optimizing the visual information in the simulated prosthetic vision has been the focus of research...
2018: International Journal of Biomedical Imaging
Kazuyuki Dei, Brett Byram
Previously, we introduced a model-based beamforming algorithm to suppress ultrasound imaging artifacts caused by clutter sources, such as reverberation and off-axis scattering. We refer to this method as aperture domain model image reconstruction (ADMIRE). In this study, we evaluated the algorithm's limitations and ability to suppress off-axis energy using Field II-based simulations, experimental phantoms and in vivo data acquired by a Verasonics ultrasound system with a curvilinear transducer (C5-2). We compared image quality derived from a standard delay-and-sum (DAS) beamformer, DAS with coherence factor (CF) weighting, ADMIRE and ADMIRE plus CF weighting...
April 25, 2018: Ultrasonics
Martin Reckziegel, Muhammad Faisal Cheema, Gerik Scheuermann, Stefan Janicke
A predominance map expresses the predominant data category for each geographical entity and colors are used to differentiate a small number of data categories. In tag maps, many data categories are present in the form of different tags, but related tag map approaches do not account for predominance, as tags are either displaced from their respective geographical locations or visual clutter occurs. We propose predominance tag maps, a layout algorithm that accounts for predominance for arbitrary aggregation granularities...
June 2018: IEEE Transactions on Visualization and Computer Graphics
Pinglei Bao, Doris Y Tsao
Object recognition in the natural world usually occurs in the presence of multiple surrounding objects, but responses of neurons in inferotemporal (IT) cortex, the large brain area responsible for object recognition, have mostly been studied only to isolated objects. We study rules governing responses to multiple objects by cells in two category-selective regions of macaque IT cortex, the middle lateral face patch (ML) and the middle body patch (MB). We find that responses of single ML and MB cells to pairs of objects can be explained by the widely accepted framework of normalization, with one added ingredient: homogeneous category selectivity of neighboring neurons forming the normalization pool...
May 2, 2018: Nature Communications
Alexander J Baldwin
Mollie Lentaigne was a medical artist who worked at the Queen Victoria Hospital in East Grinstead during the Second World War alongside Archibald McIndoe and his dedicated team. She drew hundreds of medical illustrations for McIndoe and his fellow surgeons during the years between 1940 and 1945. Her illustrations depict the plastic surgery that was carried out in that hospital on the badly burnt RAF servicemen injured during the war that took place in the skies over Europe, which included many aircrew injured during the Battle of Britain...
April 16, 2018: Journal of Plastic, Reconstructive & Aesthetic Surgery: JPRAS
Jiaqi Yang, Yang Xiao, Zhiguo Cao
The local reference frame (LRF), as an independent coordinate system constructed on the local 3D surface, is broadly employed in 3D local feature descriptors. The benefits of the LRF include rotational invariance and full 3D spatial information, thereby greatly boosting the distinctiveness of a 3D feature descriptor. There are numerous LRF methods in the literature; however, no comprehensive study comparing their repeatability and robustness performance under different application scenarios and nuisances has been conducted...
August 2018: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Douglas R Wylie, Cristián Gutiérrez-Ibáñez, Andrea H Gaede, Douglas L Altshuler, Andrew N Iwaniuk
In this paper, we review the connections and physiology of visual pathways to the cerebellum in birds and consider their role in flight. We emphasize that there are two visual pathways to the cerebellum. One is to the vestibulocerebellum (folia IXcd and X) that originates from two retinal-recipient nuclei that process optic flow: the nucleus of the basal optic root (nBOR) and the pretectal nucleus lentiformis mesencephali (LM). The second is to the oculomotor cerebellum (folia VI-VIII), which receives optic flow information, mainly from LM, but also local visual motion information from the optic tectum, and other visual information from the ventral lateral geniculate nucleus (Glv)...
2018: Frontiers in Neuroscience
Vaibhav Kakkad, Melissa LeFevre, Kingshuk Roy Choudhury, Joseph Kisslo, Gregg E Trahey
Transmit beamforming has a strong impact on several factors that govern image quality, field-of-view, and frame-rate in ultrasound imaging. For cardiac applications, the visualization of fine structures and the ability to track their motion is equally important. Consequently, beamforming choices for echocardiography aim to optimize these trade-offs. Acoustic clutter can dramatically impact image quality and degrade the diagnostic value of cardiac ultrasound imaging. Clutter levels, however, are closely tied to the choice of beamforming configuration...
April 1, 2018: Ultrasonic Imaging
Saurabh Gandhi, Eham Arora, Ajay Bhandarwar, Arun Patil, Amol Wagh, Shubham Gupta
Bezoars are intra-luminal concretions of ingested material which accumulate within the bowel. They are termed pharmacobezoars when the constituent material is drugs. We report a 64-year-old female with abdominal pain and obstipation for 3 days. Patient had completed anti-tuberculous combination therapy for suspected abdominal tuberculosis 25 years ago. She exhibited features of shock with a right iliac fossa lump. Abdominal X-ray displayed multiple air-fluid levels with densely cluttered radio-opacities in the right lower quadrant...
April 21, 2018: Clinical Journal of Gastroenterology
Milena Scaccia, Michael S Langer
In three-dimensional (3-D) cluttered scenes such as foliage, deeper surfaces often are more shadowed and hence darker, and so depth and luminance often have negative covariance. We examined whether the sign of depth-luminance covariance plays a role in depth perception in 3-D clutter. We compared scenes rendered with negative and positive depth-luminance covariance where positive covariance means that deeper surfaces are brighter and negative covariance means deeper surfaces are darker. For each scene, the sign of the depth-luminance covariance was given by occlusion cues...
March 1, 2018: Journal of Vision
Esia Belbachir, Ehsan Golkar, Bernard Bayle, Caroline Essert
PURPOSE: Percutaneous procedures allow interventional radiologists to perform diagnoses or treatments guided by an imaging device, typically a computed tomography (CT) scanner with a high spatial resolution. To reduce exposure to radiations and improve accuracy, robotic assistance to needle insertion is considered in the case of X-ray guided procedures. We introduce a planning algorithm that computes a needle placement compatible with both the patient's anatomy and the accessibility of the robot within the scanner gantry...
April 18, 2018: International Journal of Computer Assisted Radiology and Surgery
Cassandra Crone, Melissa M Norberg
BACKGROUND: Home visits can improve treatment outcomes for hoarding disorder, but factors influencing the success of home visits remain unknown. As home visits expose individuals to clutter and fear, the present study examined the effect that fear and emotional reactivity have on the relationship between clutter and discarding behaviour. METHODS: Participants with at least subclinical discarding problems (n = 143) were asked to save or discard personal possessions of varying value following an emotional induction that took place in either a tidy or cluttered context...
April 10, 2018: Journal of Affective Disorders
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