107 research outputs found
Progressive multi-atlas label fusion by dictionary evolution
AbstractAccurate segmentation of anatomical structures in medical images is important in recent imaging based studies. In the past years, multi-atlas patch-based label fusion methods have achieved a great success in medical image segmentation. In these methods, the appearance of each input image patch is first represented by an atlas patch dictionary (in the image domain), and then the latent label of the input image patch is predicted by applying the estimated representation coefficients to the corresponding anatomical labels of the atlas patches in the atlas label dictionary (in the label domain). However, due to the generally large gap between the patch appearance in the image domain and the patch structure in the label domain, the estimated (patch) representation coefficients from the image domain may not be optimal for the final label fusion, thus reducing the labeling accuracy. To address this issue, we propose a novel label fusion framework to seek for the suitable label fusion weights by progressively constructing a dynamic dictionary in a layer-by-layer manner, where the intermediate dictionaries act as a sequence of guidance to steer the transition of (patch) representation coefficients from the image domain to the label domain. Our proposed multi-layer label fusion framework is flexible enough to be applied to the existing labeling methods for improving their label fusion performance, i.e., by extending their single-layer static dictionary to the multi-layer dynamic dictionary. The experimental results show that our proposed progressive label fusion method achieves more accurate hippocampal segmentation results for the ADNI dataset, compared to the counterpart methods using only the single-layer static dictionary
Real-time Person Re-identification at the Edge: A Mixed Precision Approach
A critical part of multi-person multi-camera tracking is person
re-identification (re-ID) algorithm, which recognizes and retains identities of
all detected unknown people throughout the video stream. Many re-ID algorithms
today exemplify state of the art results, but not much work has been done to
explore the deployment of such algorithms for computation and power constrained
real-time scenarios. In this paper, we study the effect of using a light-weight
model, MobileNet-v2 for re-ID and investigate the impact of single (FP32)
precision versus half (FP16) precision for training on the server and inference
on the edge nodes. We further compare the results with the baseline model which
uses ResNet-50 on state of the art benchmarks including CUHK03, Market-1501,
and Duke-MTMC. The MobileNet-V2 mixed precision training method can improve
both inference throughput on the edge node, and training time on server
reaching to 27.77fps and , respectively and decreases
power consumption on the edge node by , while it deteriorates
accuracy only 5.6\% in respect to ResNet-50 single precision on the average for
three different datasets. The code and pre-trained networks are publicly
available at https://github.com/TeCSAR-UNCC/person-reid.Comment: This is a pre-print of an article published in International
Conference on Image Analysis and Recognition (ICIAR 2019), Lecture Notes in
Computer Science. The final authenticated version is available online at
https://doi.org/10.1007/978-3-030-27272-2_
ELODI: Ensemble Logit Difference Inhibition for Positive-Congruent Training
Negative flips are errors introduced in a classification system when a legacy
model is replaced with a new one. Existing methods to reduce the negative flip
rate (NFR) either do so at the expense of overall accuracy using model
distillation, or use ensembles, which multiply inference cost prohibitively. We
present a method to train a classification system that achieves paragon
performance in both error rate and NFR, at the inference cost of a single
model. Our method introduces a generalized distillation objective, Logit
Difference Inhibition (LDI), that penalizes changes in the logits between the
new and old model, without forcing them to coincide as in ordinary
distillation. LDI affords the model flexibility to reduce error rate along with
NFR. The method uses a homogeneous ensemble as the reference model for LDI,
hence the name Ensemble LDI, or ELODI. The reference model can then be
substituted with a single model at inference time. The method leverages the
observation that negative flips are typically not close to the decision
boundary, but often exhibit large deviations in the distance among their
logits, which are reduced by ELODI.Comment: Tech repor
Development of a Low Motion-Noise Humanoid Neck: Statics Analysis and Experimental Validation
Abstract-This paper presents our recently developed humanoid neck system that can effectively mimic motion of human neck with very low motion noises. The feature of low motion noises allows our system to work like a real human head/neck. Thus the level of acoustic noises from wearable equipments, such as donning respirators or chemical-resistant jackets, induced by human head motion can be simulated and investigated using such a system. The objective of this investigation is to facilitate using head-worn communication devices for the person who wears the protective equipment/uniform that usually produces communication-noise when the head/neck moves. Our low motion-noise humanoid neck system is based on the spring structure, which can generate 1 Degree of Freedom (DOF) jaw movement and 3DOF neck movement. To guarantee the low-noise feature, no noise-makers like gear and electrodriven parts are embedded in the head/neck structure. Instead, the motions are driven by seven cables, and the actuators pulling the cables are sealed in a sound insulation box. Furthermore, statics analysis of the system has been processed completely. Experimental results validate the analysis, and clearly show that the head/neck system can greatly mimic the motions of human head with an A-weighted noise level of 30 dB or below
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