74 research outputs found
Temporal distinguishability in Hong-Ou-Mandel interference: Generation and characterization of high-dimensional frequency entanglement
High-dimensional quantum entanglement is currently one of the most prolific
fields in quantum information processing due to its high information capacity
and error resilience. A versatile method for harnessing high-dimensional
entanglement has long been hailed as an absolute necessity in the exploration
of quantum science and technologies. Here we exploit Hong-Ou-Mandel
interference to manipulate discrete frequency entanglement in
arbitrary-dimensional Hilbert space. The generation and characterization of
two-, four- and six-dimensional frequency entangled qudits are theoretically
and experimentally investigated, allowing for the estimation of entanglement
dimensionality in the whole state space. Additionally, our strategy can be
generalized to engineer higher-dimensional entanglement in other photonic
degrees of freedom. Our results may provide a more comprehensive understanding
of frequency shaping and interference phenomena, and pave the way to more
complex high-dimensional quantum information processing protocols
Overcoming Noise in Entanglement Distribution
Noise can be considered the natural enemy of quantum information. An often
implied benefit of high-dimensional entanglement is its increased resilience to
noise. However, manifesting this potential in an experimentally meaningful
fashion is challenging and has never been done before. In infinite dimensional
spaces, discretisation is inevitable and renders the effective dimension of
quantum states a tunable parameter. Owing to advances in experimental
techniques and theoretical tools, we demonstrate an increased resistance to
noise by identifying two pathways to exploit high-dimensional entangled states.
Our study is based on two separate experiments utilising canonical
spatio-temporal properties of entangled photon pairs. Following these different
pathways to noise resilience, we are able to certify entanglement in the
photonic orbital-angular-momentum and energy-time degrees of freedom up to
noise conditions corresponding to a noise fraction of 72 % and 92 %
respectively. Our work paves the way towards practical quantum communication
systems that are able to surpass current noise and distance limitations, while
not compromising on potential device-independence.Comment: 12 pages main text, 7 pages supplementary information, 6 figure
CryoNuSeg: A Dataset for Nuclei Instance Segmentation of Cryosectioned H&E-Stained Histological Images
Nuclei instance segmentation plays an important role in the analysis of
Hematoxylin and Eosin (H&E)-stained images. While supervised deep learning
(DL)-based approaches represent the state-of-the-art in automatic nuclei
instance segmentation, annotated datasets are required to train these models.
There are two main types of tissue processing protocols, namely formalin-fixed
paraffin-embedded samples (FFPE) and frozen tissue samples (FS). Although
FFPE-derived H&E stained tissue sections are the most widely used samples, H&E
staining on frozen sections derived from FS samples is a relevant method in
intra-operative surgical sessions as it can be performed fast. Due to
differences in the protocols of these two types of samples, the derived images
and in particular the nuclei appearance may be different in the acquired whole
slide images. Analysis of FS-derived H&E stained images can be more challenging
as rapid preparation, staining, and scanning of FS sections may lead to
deterioration in image quality.
In this paper, we introduce CryoNuSeg, the first fully annotated FS-derived
cryosectioned and H&E-stained nuclei instance segmentation dataset. The dataset
contains images from 10 human organs that were not exploited in other publicly
available datasets, and is provided with three manual mark-ups to allow
measuring intra-observer and inter-observer variability. Moreover, we
investigate the effects of tissue fixation/embedding protocol (i.e., FS or
FFPE) on the automatic nuclei instance segmentation performance of one of the
state-of-the-art DL approaches. We also create a baseline segmentation
benchmark for the dataset that can be used in future research.
A step-by-step guide to generate the dataset as well as the full dataset and
other detailed information are made available to fellow researchers at
https://github.com/masih4/CryoNuSeg
Polarization entanglement by time-reversed Hong-Ou-Mandel interference
Sources of entanglement are an enabling resource in quantum technology, and
pushing the limits of generation rate and quality of entanglement is a
necessary pre-requisite towards practical applications. Here, we present an
ultra-bright source of polarization-entangled photon pairs based on
time-reversed Hong-Ou-Mandel interference. By superimposing four pair-creation
possibilities on a polarization beam splitter, pairs of identical photons are
separated into two spatial modes without the usual requirement for wavelength
distinguishability or non-collinear emission angles. Our source yields
high-fidelity polarization entanglement and high pair-generation rates without
any requirement for active interferometric stabilization, which makes it an
ideal candidate for a variety of applications, in particular those requiring
indistinguishable photons
Fusing fine-tuned deep features for skin lesion classification
© 2018 Elsevier Ltd Malignant melanoma is one of the most aggressive forms of skin cancer. Early detection is important as it significantly improves survival rates. Consequently, accurate discrimination of malignant skin lesions from benign lesions such as seborrheic keratoses or benign nevi is crucial, while accurate computerised classification of skin lesion images is of great interest to support diagnosis. In this paper, we propose a fully automatic computerised method to classify skin lesions from dermoscopic images. Our approach is based on a novel ensemble scheme for convolutional neural networks (CNNs) that combines intra-architecture and inter-architecture network fusion. The proposed method consists of multiple sets of CNNs of different architecture that represent different feature abstraction levels. Each set of CNNs consists of a number of pre-trained networks that have identical architecture but are fine-tuned on dermoscopic skin lesion images with different settings. The deep features of each network were used to train different support vector machine classifiers. Finally, the average prediction probability classification vectors from different sets are fused to provide the final prediction. Evaluated on the 600 test images of the ISIC 2017 skin lesion classification challenge, the proposed algorithm yields an area under receiver operating characteristic curve of 87.3% for melanoma classification and an area under receiver operating characteristic curve of 95.5% for seborrheic keratosis classification, outperforming the top-ranked methods of the challenge while being simpler compared to them. The obtained results convincingly demonstrate our proposed approach to represent a reliable and robust method for feature extraction, model fusion and classification of dermoscopic skin lesion images
- …