562 research outputs found
Spectral-spatial classification of hyperspectral images: three tricks and a new supervised learning setting
Spectral-spatial classification of hyperspectral images has been the subject
of many studies in recent years. In the presence of only very few labeled
pixels, this task becomes challenging. In this paper we address the following
two research questions: 1) Can a simple neural network with just a single
hidden layer achieve state of the art performance in the presence of few
labeled pixels? 2) How is the performance of hyperspectral image classification
methods affected when using disjoint train and test sets? We give a positive
answer to the first question by using three tricks within a very basic shallow
Convolutional Neural Network (CNN) architecture: a tailored loss function, and
smooth- and label-based data augmentation. The tailored loss function enforces
that neighborhood wavelengths have similar contributions to the features
generated during training. A new label-based technique here proposed favors
selection of pixels in smaller classes, which is beneficial in the presence of
very few labeled pixels and skewed class distributions. To address the second
question, we introduce a new sampling procedure to generate disjoint train and
test set. Then the train set is used to obtain the CNN model, which is then
applied to pixels in the test set to estimate their labels. We assess the
efficacy of the simple neural network method on five publicly available
hyperspectral images. On these images our method significantly outperforms
considered baselines. Notably, with just 1% of labeled pixels per class, on
these datasets our method achieves an accuracy that goes from 86.42%
(challenging dataset) to 99.52% (easy dataset). Furthermore we show that the
simple neural network method improves over other baselines in the new
challenging supervised setting. Our analysis substantiates the highly
beneficial effect of using the entire image (so train and test data) for
constructing a model.Comment: Remote Sensing 201
A novel spectral-spatial singular spectrum analysis technique for near real-time in-situ feature extraction in hyperspectral imaging.
As a cutting-edge technique for denoising and feature extraction, singular spectrum analysis (SSA) has been applied successfully for feature mining in hyperspectral images (HSI). However, when applying SSA for in situ feature extraction in HSI, conventional pixel-based 1-D SSA fails to produce satisfactory results, while the band-image-based 2D-SSA is also infeasible especially for the popularly used line-scan mode. To tackle these challenges, in this article, a novel 1.5D-SSA approach is proposed for in situ spectral-spatial feature extraction in HSI, where pixels from a small window are used as spatial information. For each sequentially acquired pixel, similar pixels are located from a window centered at the pixel to form an extended trajectory matrix for feature extraction. Classification results on two well-known benchmark HSI datasets and an actual urban scene dataset have demonstrated that the proposed 1.5D-SSA achieves the superior performance compared with several state-of-the-art spectral and spatial methods. In addition, the near real-time implementation in aligning to the HSI acquisition process can meet the requirement of online image analysis for more efficient feature extraction than the conventional offline workflow
A novel band selection and spatial noise reduction method for hyperspectral image classification.
As an essential reprocessing method, dimensionality reduction (DR) can reduce the data redundancy and improve the performance of hyperspectral image (HSI) classification. A novel unsupervised DR framework with feature interpretability, which integrates both band selection (BS) and spatial noise reduction method, is proposed to extract low-dimensional spectral-spatial features of HSI. We proposed a new Neighboring band Grouping and Normalized Matching Filter (NGNMF) for BS, which can reduce the data dimension whilst preserve the corresponding spectral information. An enhanced 2-D singular spectrum analysis (E2DSSA) method is also proposed to extract the spatial context and structural information from each selected band, aiming to decrease the intra-class variability and reduce the effect of noise in the spatial domain. The support vector machine (SVM) classifier is used to evaluate the effectiveness of the extracted spectral-spatial low-dimensional features. Experimental results on three publicly available HSI datasets have fully demonstrated the efficacy of the proposed NGNMF-E2DSSA method, which has surpassed a number of state-of-the-art DR methods
Introduction to Facial Micro Expressions Analysis Using Color and Depth Images: A Matlab Coding Approach (Second Edition, 2023)
The book attempts to introduce a gentle introduction to the field of Facial
Micro Expressions Recognition (FMER) using Color and Depth images, with the aid
of MATLAB programming environment. FMER is a subset of image processing and it
is a multidisciplinary topic to analysis. So, it requires familiarity with
other topics of Artifactual Intelligence (AI) such as machine learning, digital
image processing, psychology and more. So, it is a great opportunity to write a
book which covers all of these topics for beginner to professional readers in
the field of AI and even without having background of AI. Our goal is to
provide a standalone introduction in the field of MFER analysis in the form of
theorical descriptions for readers with no background in image processing with
reproducible Matlab practical examples. Also, we describe any basic definitions
for FMER analysis and MATLAB library which is used in the text, that helps
final reader to apply the experiments in the real-world applications. We
believe that this book is suitable for students, researchers, and professionals
alike, who need to develop practical skills, along with a basic understanding
of the field. We expect that, after reading this book, the reader feels
comfortable with different key stages such as color and depth image processing,
color and depth image representation, classification, machine learning, facial
micro-expressions recognition, feature extraction and dimensionality reduction.
The book attempts to introduce a gentle introduction to the field of Facial
Micro Expressions Recognition (FMER) using Color and Depth images, with the aid
of MATLAB programming environment.Comment: This is the second edition of the boo
Authentication of Amadeo de Souza-Cardoso Paintings and Drawings With Deep Learning
Art forgery has a long-standing history that can be traced back to the Roman period and
has become more rampant as the art market continues prospering. Reports disclosed that
uncountable artworks circulating on the art market could be fake. Even some principal
art museums and galleries could be exhibiting a good percentage of fake artworks. It
is therefore substantially important to conserve cultural heritage, safeguard the interest
of both the art market and the artists, as well as the integrity of artists’ legacies. As a
result, art authentication has been one of the most researched and well-documented fields
due to the ever-growing commercial art market in the past decades. Over the past years,
the employment of computer science in the art world has flourished as it continues to
stimulate interest in both the art world and the artificial intelligence arena. In particular, the
implementation of Artificial Intelligence, namely Deep Learning algorithms and Neural
Networks, has proved to be of significance for specialised image analysis. This research
encompassed multidisciplinary studies on chemistry, physics, art and computer science.
More specifically, the work presents a solution to the problem of authentication of heritage
artwork by Amadeo de Souza-Cardoso, namely paintings, through the use of artificial
intelligence algorithms. First, an authenticity estimation is obtained based on processing of
images through a deep learning model that analyses the brushstroke features of a painting.
Iterative, multi-scale analysis of the images is used to cover the entire painting and produce
an overall indication of authenticity. Second, a mixed input, deep learning model is
proposed to analyse pigments in a painting. This solves the image colour segmentation
and pigment classification problem using hyperspectral imagery. The result is used to
provide an indication of authenticity based on pigment classification and correlation with
chemical data obtained via XRF analysis. Further algorithms developed include a deep
learning model that tackles the pigment unmixing problem based on hyperspectral data.
Another algorithm is a deep learning model that estimates hyperspectral images from
sRGB images. Based on the established algorithms and results obtained, two applications
were developed. First, an Augmented Reality mobile application specifically for the
visualisation of pigments in the artworks by Amadeo. The mobile application targets the
general public, i.e., art enthusiasts, museum visitors, art lovers or art experts. And second, a desktop application with multiple purposes, such as the visualisation of pigments and
hyperspectral data. This application is designed for art specialists, i.e., conservators and
restorers. Due to the special circumstances of the pandemic, trials on the usage of these
applications were only performed within the Department of Conservation and Restoration
at NOVA University Lisbon, where both applications received positive feedback.A falsificação de arte tem uma história de longa data que remonta ao período romano
e tornou-se mais desenfreada à medida que o mercado de arte continua a prosperar.
Relatórios revelaram que inúmeras obras de arte que circulam no mercado de arte podem
ser falsas. Mesmo alguns dos principais museus e galerias de arte poderiam estar exibindo
uma boa porcentagem de obras de arte falsas. Por conseguinte, é extremamente importante
conservar o património cultural, salvaguardar os interesses do mercado da arte e dos artis-
tas, bem como a integridade dos legados dos artistas. Como resultado, a autenticação de
arte tem sido um dos campos mais pesquisados e bem documentados devido ao crescente
mercado de arte comercial nas últimas décadas.Nos últimos anos, o emprego da ciência
da computação no mundo da arte floresceu à medida que continua a estimular o interesse
no mundo da arte e na arena da inteligência artificial. Em particular, a implementação da
Inteligência Artificial, nomeadamente algoritmos de aprendizagem profunda (ou Deep
Learning) e Redes Neuronais, tem-se revelado importante para a análise especializada de
imagens.Esta investigação abrangeu estudos multidisciplinares em química, física, arte e
informática. Mais especificamente, o trabalho apresenta uma solução para o problema da
autenticação de obras de arte patrimoniais de Amadeo de Souza-Cardoso, nomeadamente
pinturas, através da utilização de algoritmos de inteligência artificial. Primeiro, uma esti-
mativa de autenticidade é obtida com base no processamento de imagens através de um
modelo de aprendizagem profunda que analisa as características de pincelada de uma
pintura. A análise iterativa e multiescala das imagens é usada para cobrir toda a pintura e
produzir uma indicação geral de autenticidade. Em segundo lugar, um modelo misto de
entrada e aprendizagem profunda é proposto para analisar pigmentos em uma pintura.
Isso resolve o problema de segmentação de cores de imagem e classificação de pigmentos
usando imagens hiperespectrais. O resultado é usado para fornecer uma indicação de
autenticidade com base na classificação do pigmento e correlação com dados químicos
obtidos através da análise XRF. Outros algoritmos desenvolvidos incluem um modelo
de aprendizagem profunda que aborda o problema da desmistura de pigmentos com
base em dados hiperespectrais. Outro algoritmo é um modelo de aprendizagem profunda
estabelecidos e nos resultados obtidos, foram desenvolvidas duas aplicações. Primeiro,
uma aplicação móvel de Realidade Aumentada especificamente para a visualização de
pigmentos nas obras de Amadeo. A aplicação móvel destina-se ao público em geral, ou
seja, entusiastas da arte, visitantes de museus, amantes da arte ou especialistas em arte.
E, em segundo lugar, uma aplicação de ambiente de trabalho com múltiplas finalidades,
como a visualização de pigmentos e dados hiperespectrais. Esta aplicação é projetada para
especialistas em arte, ou seja, conservadores e restauradores. Devido às circunstâncias
especiais da pandemia, os ensaios sobre a utilização destas aplicações só foram realizados
no âmbito do Departamento de Conservação e Restauro da Universidade NOVA de Lisboa,
onde ambas as candidaturas receberam feedback positivo
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