42 research outputs found
Seeing the Unheard: dynamics of thin liquid film in holographic ultrasonic field revealed by time-resolved Schlieren imaging
In this study, we introduce a unique approach that employs time-resolved
Schlieren imaging to capture and visualize the dynamic changes of a thin liquid
(mixture of water, soap and glycerin) film in ultrasonic wave field with high
spatial and temporal resolution. By placing a soap film spanning a wire frame
vertically in the path of light, we harnessed the vibrations induced by the
ultrasonic waves, resulting in remarkable Schlieren imaging patterns. The
investigation not only uncovers an unexpected branch flow phenomenon within the
film, challenging existing assumptions, but also reveals a fascinating
interplay between vortex flow and branch flow. The experiments have revealed a
captivating spectrum of dynamic phenomena within the thin liquid films. The
observation of small-scale capillary waves, large-scale standing waves,
traveling waves, and the intricate fusion of capillary-gravity wave patterns
underscores the rich complexity inherent in the interaction between the films
and the holographic ultrasonic wave field. These diverse states of film
dynamics provide a comprehensive understanding of the intricate interplay
between various wave modes and fluid behavior, further enhancing comprehension
of this fascinating phenomenon. The ability to visualize the pressure field
opens up new avenues for optimizing acoustic levitation techniques,
investigating particle behavior, and exploring potential applications in
materials science and bioengineering.Comment: 10 pages, 8 page
QR-CLIP: Introducing Explicit Open-World Knowledge for Location and Time Reasoning
Daily images may convey abstract meanings that require us to memorize and
infer profound information from them. To encourage such human-like reasoning,
in this work, we teach machines to predict where and when it was taken rather
than performing basic tasks like traditional segmentation or classification.
Inspired by Horn's QR theory, we designed a novel QR-CLIP model consisting of
two components: 1) the Quantity module first retrospects more open-world
knowledge as the candidate language inputs; 2) the Relevance module carefully
estimates vision and language cues and infers the location and time.
Experiments show our QR-CLIP's effectiveness, and it outperforms the previous
SOTA on each task by an average of about 10% and 130% relative lift in terms of
location and time reasoning. This study lays a technical foundation for
location and time reasoning and suggests that effectively introducing
open-world knowledge is one of the panaceas for the tasks.Comment: Technical Report. Github: https://github.com/Shi-Wm/QR-CLI
Continual Segment: Towards a Single, Unified and Accessible Continual Segmentation Model of 143 Whole-body Organs in CT Scans
Deep learning empowers the mainstream medical image segmentation methods.
Nevertheless current deep segmentation approaches are not capable of
efficiently and effectively adapting and updating the trained models when new
incremental segmentation classes (along with new training datasets or not) are
required to be added. In real clinical environment, it can be preferred that
segmentation models could be dynamically extended to segment new organs/tumors
without the (re-)access to previous training datasets due to obstacles of
patient privacy and data storage. This process can be viewed as a continual
semantic segmentation (CSS) problem, being understudied for multi-organ
segmentation. In this work, we propose a new architectural CSS learning
framework to learn a single deep segmentation model for segmenting a total of
143 whole-body organs. Using the encoder/decoder network structure, we
demonstrate that a continually-trained then frozen encoder coupled with
incrementally-added decoders can extract and preserve sufficiently
representative image features for new classes to be subsequently and validly
segmented. To maintain a single network model complexity, we trim each decoder
progressively using neural architecture search and teacher-student based
knowledge distillation. To incorporate with both healthy and pathological
organs appearing in different datasets, a novel anomaly-aware and confidence
learning module is proposed to merge the overlapped organ predictions,
originated from different decoders. Trained and validated on 3D CT scans of
2500+ patients from four datasets, our single network can segment total 143
whole-body organs with very high accuracy, closely reaching the upper bound
performance level by training four separate segmentation models (i.e., one
model per dataset/task)
Experimental and Numerical Investigation of Micro/Mini Channel Flow-Boiling Heat Transfer with Non-Uniform Circumferential Heat Fluxes at Different Rotational Orientations
Flow-boiling of Perfluorohexane (FC-72) in horizontal micro/mini channels was investigated experimen- tally and numerically at different rotational orientations in terms of gravity. One-sided uniform channel heating was considered experimentally for rotational angles ranging from 0 °(heating from below) to 180 °(heating from above) in increments of 30 °. The micro/mini channel had a high aspect ratio of 10 (5 mm x 0.5 mm) and a hydraulic diameter of 909 μm. In-channel flow visualisations were recorded and heat transfer coefficients were determined for mass fluxes of 10, 20 and 40 kg/m 2 s at a saturation temperature of 56 °C. Suitable heat fluxes were applied to span the onset of nucleate boiling to near dry-out conditions within the channel. It was found that the rotational angle had a significant influence on the heat transfer performance due to its influence on bubble detachment. Bottom-heated cases (0 °orientation) resulted in local heat transfer coefficients that were up to 201% higher than for any other rotational orientation. Channel orientations of 60 °(slanted heating surface) and 90 °(heating from the side) generally produced the lowest local heat transfer coefficients. Insight into the influence of the grav- itational orientation on single-bubble growth within the nucleation and detachment region was obtained via two- and three-dimensional numerical simulations. Bubble behaviour after detachment and its effect on heat transfer were also investigated transiently until detachment. The numerical simulations mirrored the experimental trends and it was found that the presence of growing bubbles interrupted the velocity streamlines and the thermal boundary layer downstream of the nucleation sit
Holistic classification of CT attenuation patterns for interstitial lung diseases via deep convolutional neural networks
Interstitial lung diseases (ILD) involve several abnormal imaging patterns observed in computed tomography (CT) images. Accurate classification of these patterns plays a significant role in precise clinical decision making of the extent and nature of the diseases. Therefore it is important for developing automated pulmonary computer-aided detection (CAD) systems. Conventionally, this task relies on experts’ manual identification of regions of interest (ROIs) as a prerequisite to diagnose potential diseases. This protocol is time consuming and inhibits fully automatic assessment. In this paper, we present a new method to classify ILD imaging patterns on CT images. The main difference is that the proposed algorithm uses the entire image as a holistic input. By circumventing the prerequisite of manually input ROIs, our problem setup is significantly more difficult than previous work but can better address the clinical workflow. Qualitative and quantitative results using a publicly available ILD database demonstrates state-of-the-art classification accuracy under the patch based classification and shows the potential of predicting the ILD type using holistic image