1,197 research outputs found
Learning from text and images: generative and discriminative models for partially labeled data
Image annotation is a challenging task of assigning keywords to an image given the content of an image. It has a variety of applications in multi-media data-mining and computer vision. Traditional machine learning approaches to image annotation require large amounts of labeled data. This requirement is often unrealistic, as obtaining labeled data is, in general, expensive and time consuming. However, large amounts of weakly labeled data and tagged images is readily available, in particular in the web and social network communities. In this thesis we address the problem of image annotation using weak supervision. In particular, we formulate the problem of image annotation as multiple instance multiple label learning problem and propose generative and discriminative models to tackle this learning problem. Multiple instance multiple label learning is a generalization of supervised learning in which the training examples are bags of instances and each bag is labeled with a set of labels. We explore two learning frameworks: generative and discriminative, and propose models within each framework to address the problem of assigning text keywords to images.
The first approach, the generative model attempts to describe the process according to which the data was generated, and then learn its parameters from the data. This model is a non-parametric generalization of the known mixture model used in the past. We extend this model to a Hierarchical Dirichlet Process which allows for countably infinite mixture components. Our experimental evaluation shows that the performance of this model does not depend on the number of mixture components, unlike the standard mixture model which suffers from over-fitting for a large number of mixture components.
The second approach is a discriminative model, which unlike generative model answers the following question: given the input bag of instances what is the most likely assignment of labels to the bag. We address this problem by learning as many classifiers as there are possible labels and force the classifiers to share weights using trace-norm regularization. We show that the performance of this model is comparable to the state-of-the-art multiple instance multiple label classifiers and that unlike some state-of-the-art models, it is scalable and practical for datasets with a large number of training instances and possible labels.
Finally we generalize the discriminative model to a semi-supervised setting to allow the model take advantage of labeled and unlabeled data. We do so by assuming that the data lies in a low-dimensional manifold and introducing a penalty that enforces the classifiers assign similar labels to indirectly similar instances (i.e. instances that are near-by in the manifold space). The manifold is learned by constructing a similarity neighborhood graph over bags, and then graph-Laplacian is used to compute the penalty term
Tag2Text: Guiding Vision-Language Model via Image Tagging
This paper presents Tag2Text, a vision language pre-training (VLP) framework,
which introduces image tagging into vision-language models to guide the
learning of visual-linguistic features. In contrast to prior works which
utilize object tags either manually labeled or automatically detected with a
limited detector, our approach utilizes tags parsed from its paired text to
learn an image tagger and meanwhile provides guidance to vision-language
models. Given that, Tag2Text can utilize large-scale annotation-free image tags
in accordance with image-text pairs, and provides more diverse tag categories
beyond objects. As a result, Tag2Text achieves a superior image tag recognition
ability by exploiting fine-grained text information. Moreover, by leveraging
tagging guidance, Tag2Text effectively enhances the performance of
vision-language models on both generation-based and alignment-based tasks.
Across a wide range of downstream benchmarks, Tag2Text achieves
state-of-the-art or competitive results with similar model sizes and data
scales, demonstrating the efficacy of the proposed tagging guidance
Autoencoding the Retrieval Relevance of Medical Images
Content-based image retrieval (CBIR) of medical images is a crucial task that
can contribute to a more reliable diagnosis if applied to big data. Recent
advances in feature extraction and classification have enormously improved CBIR
results for digital images. However, considering the increasing accessibility
of big data in medical imaging, we are still in need of reducing both memory
requirements and computational expenses of image retrieval systems. This work
proposes to exclude the features of image blocks that exhibit a low encoding
error when learned by a autoencoder (). We examine the
histogram of autoendcoding errors of image blocks for each image class to
facilitate the decision which image regions, or roughly what percentage of an
image perhaps, shall be declared relevant for the retrieval task. This leads to
reduction of feature dimensionality and speeds up the retrieval process. To
validate the proposed scheme, we employ local binary patterns (LBP) and support
vector machines (SVM) which are both well-established approaches in CBIR
research community. As well, we use IRMA dataset with 14,410 x-ray images as
test data. The results show that the dimensionality of annotated feature
vectors can be reduced by up to 50% resulting in speedups greater than 27% at
expense of less than 1% decrease in the accuracy of retrieval when validating
the precision and recall of the top 20 hits.Comment: To appear in proceedings of The 5th International Conference on Image
Processing Theory, Tools and Applications (IPTA'15), Nov 10-13, 2015,
Orleans, Franc
Recent Advances in Transfer Learning for Cross-Dataset Visual Recognition: A Problem-Oriented Perspective
This paper takes a problem-oriented perspective and presents a comprehensive
review of transfer learning methods, both shallow and deep, for cross-dataset
visual recognition. Specifically, it categorises the cross-dataset recognition
into seventeen problems based on a set of carefully chosen data and label
attributes. Such a problem-oriented taxonomy has allowed us to examine how
different transfer learning approaches tackle each problem and how well each
problem has been researched to date. The comprehensive problem-oriented review
of the advances in transfer learning with respect to the problem has not only
revealed the challenges in transfer learning for visual recognition, but also
the problems (e.g. eight of the seventeen problems) that have been scarcely
studied. This survey not only presents an up-to-date technical review for
researchers, but also a systematic approach and a reference for a machine
learning practitioner to categorise a real problem and to look up for a
possible solution accordingly
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Semantic Concept Co-Occurrence Patterns for Image Annotation and Retrieval.
Describing visual image contents by semantic concepts is an effective and straightforward way to facilitate various high level applications. Inferring semantic concepts from low-level pictorial feature analysis is challenging due to the semantic gap problem, while manually labeling concepts is unwise because of a large number of images in both online and offline collections. In this paper, we present a novel approach to automatically generate intermediate image descriptors by exploiting concept co-occurrence patterns in the pre-labeled training set that renders it possible to depict complex scene images semantically. Our work is motivated by the fact that multiple concepts that frequently co-occur across images form patterns which could provide contextual cues for individual concept inference. We discover the co-occurrence patterns as hierarchical communities by graph modularity maximization in a network with nodes and edges representing concepts and co-occurrence relationships separately. A random walk process working on the inferred concept probabilities with the discovered co-occurrence patterns is applied to acquire the refined concept signature representation. Through experiments in automatic image annotation and semantic image retrieval on several challenging datasets, we demonstrate the effectiveness of the proposed concept co-occurrence patterns as well as the concept signature representation in comparison with state-of-the-art approaches
IMAGE RETRIEVAL BASED ON COMPLEX DESCRIPTIVE QUERIES
The amount of visual data such as images and videos available over web has increased exponentially over the last few years. In order to efficiently organize and exploit these massive collections, a system, apart from being able to answer simple classification based questions such as whether a specific object is present (or absent) in an image, should also be capable of searching images and videos based on more complex descriptive questions. There is also a considerable amount of structure present in the visual world which, if effectively utilized, can help achieve this goal. To this end, we first present an approach for image ranking and retrieval based on queries consisting of multiple semantic attributes. We further show that there are significant correlations present between these attributes and accounting for them can lead to superior performance. Next, we extend this by proposing an image retrieval framework for descriptive queries composed of object categories, semantic attributes and spatial relationships. The proposed framework also includes a unique multi-view hashing technique, which enables query specification in three different modalities - image, sketch and text.
We also demonstrate the effectiveness of leveraging contextual information to reduce the supervision requirements for learning object and scene recognition models. We present an active learning framework to simultaneously learn appearance and contextual models for scene understanding. Within this framework we introduce new kinds of labeling questions that are designed to collect appearance as well as contextual information and which mimic the way in which humans actively learn about their environment. Furthermore we explicitly model the contextual interactions between the regions within an image and select the question which leads to the maximum reduction in the combined entropy of all the regions in the image (image entropy)
Knowledge Graphs Meet Multi-Modal Learning: A Comprehensive Survey
Knowledge Graphs (KGs) play a pivotal role in advancing various AI
applications, with the semantic web community's exploration into multi-modal
dimensions unlocking new avenues for innovation. In this survey, we carefully
review over 300 articles, focusing on KG-aware research in two principal
aspects: KG-driven Multi-Modal (KG4MM) learning, where KGs support multi-modal
tasks, and Multi-Modal Knowledge Graph (MM4KG), which extends KG studies into
the MMKG realm. We begin by defining KGs and MMKGs, then explore their
construction progress. Our review includes two primary task categories:
KG-aware multi-modal learning tasks, such as Image Classification and Visual
Question Answering, and intrinsic MMKG tasks like Multi-modal Knowledge Graph
Completion and Entity Alignment, highlighting specific research trajectories.
For most of these tasks, we provide definitions, evaluation benchmarks, and
additionally outline essential insights for conducting relevant research.
Finally, we discuss current challenges and identify emerging trends, such as
progress in Large Language Modeling and Multi-modal Pre-training strategies.
This survey aims to serve as a comprehensive reference for researchers already
involved in or considering delving into KG and multi-modal learning research,
offering insights into the evolving landscape of MMKG research and supporting
future work.Comment: Ongoing work; 41 pages (Main Text), 55 pages (Total), 11 Tables, 13
Figures, 619 citations; Paper list is available at
https://github.com/zjukg/KG-MM-Surve
Evaluation Methodologies for Visual Information Retrieval and Annotation
Die automatisierte Evaluation von Informations-Retrieval-Systemen erlaubt
Performanz und Qualität der Informationsgewinnung zu bewerten. Bereits in
den 60er Jahren wurden erste Methodologien für die system-basierte
Evaluation aufgestellt und in den Cranfield Experimenten überprüft.
Heutzutage gehören Evaluation, Test und Qualitätsbewertung zu einem aktiven
Forschungsfeld mit erfolgreichen Evaluationskampagnen und etablierten
Methoden. Evaluationsmethoden fanden zunächst in der Bewertung von
Textanalyse-Systemen Anwendung. Mit dem rasanten Voranschreiten der
Digitalisierung wurden diese Methoden sukzessive auf die Evaluation von
Multimediaanalyse-Systeme übertragen. Dies geschah häufig, ohne die
Evaluationsmethoden in Frage zu stellen oder sie an die veränderten
Gegebenheiten der Multimediaanalyse anzupassen. Diese Arbeit beschäftigt
sich mit der system-basierten Evaluation von Indizierungssystemen für
Bildkollektionen. Sie adressiert drei Problemstellungen der Evaluation von
Annotationen: Nutzeranforderungen für das Suchen und Verschlagworten von
Bildern, Evaluationsmaße für die Qualitätsbewertung von
Indizierungssystemen und Anforderungen an die Erstellung visueller
Testkollektionen. Am Beispiel der Evaluation automatisierter
Photo-Annotationsverfahren werden relevante Konzepte mit Bezug zu
Nutzeranforderungen diskutiert, Möglichkeiten zur Erstellung einer
zuverlässigen Ground Truth bei geringem Kosten- und Zeitaufwand vorgestellt
und Evaluationsmaße zur Qualitätsbewertung eingeführt, analysiert und
experimentell verglichen. Traditionelle Maße zur Ermittlung der Performanz
werden in vier Dimensionen klassifiziert. Evaluationsmaße vergeben
üblicherweise binäre Kosten für korrekte und falsche Annotationen. Diese
Annahme steht im Widerspruch zu der Natur von Bildkonzepten. Das gemeinsame
Auftreten von Bildkonzepten bestimmt ihren semantischen Zusammenhang und
von daher sollten diese auch im Zusammenhang auf ihre Richtigkeit hin
überprüft werden. In dieser Arbeit wird aufgezeigt, wie semantische
Ähnlichkeiten visueller Konzepte automatisiert abgeschätzt und in den
Evaluationsprozess eingebracht werden können. Die Ergebnisse der Arbeit
inkludieren ein Nutzermodell für die konzeptbasierte Suche von Bildern,
eine vollständig bewertete Testkollektion und neue Evaluationsmaße für die
anforderungsgerechte Qualitätsbeurteilung von Bildanalysesystemen.Performance assessment plays a major role in the research on Information
Retrieval (IR) systems. Starting with the Cranfield experiments in the
early 60ies, methodologies for the system-based performance assessment
emerged and established themselves, resulting in an active research field
with a number of successful benchmarking activities. With the rise of the
digital age, procedures of text retrieval evaluation were often transferred
to multimedia retrieval evaluation without questioning their direct
applicability. This thesis investigates the problem of system-based
performance assessment of annotation approaches in generic image
collections. It addresses three important parts of annotation evaluation,
namely user requirements for the retrieval of annotated visual media,
performance measures for multi-label evaluation, and visual test
collections. Using the example of multi-label image annotation evaluation,
I discuss which concepts to employ for indexing, how to obtain a reliable
ground truth to moderate costs, and which evaluation measures are
appropriate. This is accompanied by a thorough analysis of related work on
system-based performance assessment in Visual Information Retrieval (VIR).
Traditional performance measures are classified into four dimensions and
investigated according to their appropriateness for visual annotation
evaluation. One of the main ideas in this thesis adheres to the common
assumption on the binary nature of the score prediction dimension in
annotation evaluation. However, the predicted concepts and the set of true
indexed concepts interrelate with each other. This work will show how to
utilise these semantic relationships for a fine-grained evaluation
scenario. Outcomes of this thesis result in a user model for concept-based
image retrieval, a fully assessed image annotation test collection, and a
number of novel performance measures for image annotation evaluation
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