Search Results for author: Ondřej Chum

Found 21 papers, 15 papers with code

ILIAS: Instance-Level Image retrieval At Scale

no code implementations17 Feb 2025 Giorgos Kordopatis-Zilos, Vladan Stojnić, Anna Manko, Pavel Šuma, Nikolaos-Antonios Ypsilantis, Nikos Efthymiadis, Zakaria Laskar, Jiří Matas, Ondřej Chum, Giorgos Tolias

An extensive benchmarking is performed with the following observations: i) models fine-tuned on specific domains, such as landmarks or products, excel in that domain but fail on ILIAS ii) learning a linear adaptation layer using multi-domain class supervision results in performance improvements, especially for vision-language models iii) local descriptors in retrieval re-ranking are still a key ingredient, especially in the presence of severe background clutter iv) the text-to-image performance of the vision-language foundation models is surprisingly close to the corresponding image-to-image case.

Benchmarking Image Retrieval +2

Composed Image Retrieval for Training-Free Domain Conversion

1 code implementation4 Dec 2024 Nikos Efthymiadis, Bill Psomas, Zakaria Laskar, Konstantinos Karantzalos, Yannis Avrithis, Ondřej Chum, Giorgos Tolias

This work addresses composed image retrieval in the context of domain conversion, where the content of a query image is retrieved in the domain specified by the query text.

Image Retrieval Language Modeling +3

Co-Segmentation without any Pixel-level Supervision with Application to Large-Scale Sketch Classification

no code implementations17 Oct 2024 Nikolaos-Antonios Ypsilantis, Ondřej Chum

This work proposes a novel method for object co-segmentation, i. e. pixel-level localization of a common object in a set of images, that uses no pixel-level supervision for training.

Object Localization Sketch Recognition

UDON: Universal Dynamic Online distillatioN for generic image representations

1 code implementation12 Jun 2024 Nikolaos-Antonios Ypsilantis, KaiFeng Chen, André Araujo, Ondřej Chum

This boosts significantly the learning of complex domains which are characterised by a large number of classes and long-tail distributions.

Minimal Solvers for Rectifying from Radially-Distorted Conjugate Translations

1 code implementation4 Nov 2019 James Pritts, Zuzana Kukelova, Viktor Larsson, Yaroslava Lochman, Ondřej Chum

This paper introduces minimal solvers that jointly solve for radial lens undistortion and affine-rectification using local features extracted from the image of coplanar translated and reflected scene texture, which is common in man-made environments.

Targeted Mismatch Adversarial Attack: Query with a Flower to Retrieve the Tower

1 code implementation ICCV 2019 Giorgos Tolias, Filip Radenovic, Ondřej Chum

We show successful attacks to partially unknown systems, by designing various loss functions for the adversarial image construction.

Adversarial Attack Retrieval

No Fear of the Dark: Image Retrieval under Varying Illumination Conditions

1 code implementation ICCV 2019 Tomas Jenicek, Ondřej Chum

Image retrieval under varying illumination conditions, such as day and night images, is addressed by image preprocessing, both hand-crafted and learned.

Image Retrieval Retrieval

Minimal Solvers for Rectifying from Radially-Distorted Scales and Change of Scales

1 code implementation25 Jul 2019 James Pritts, Zuzana Kukelova, Viktor Larsson, Yaroslava Lochman, Ondřej Chum

The proposed solvers use the affine invariant that coplanar repeats have the same scale in rectified space.

Linking Art through Human Poses

no code implementations8 Jul 2019 Tomas Jenicek, Ondřej Chum

We address the discovery of composition transfer in artworks based on their visual content.

Content-Based Image Retrieval Retrieval

Understanding and Improving Kernel Local Descriptors

3 code implementations27 Nov 2018 Arun Mukundan, Giorgos Tolias, Andrei Bursuc, Hervé Jégou, Ondřej Chum

We propose a multiple-kernel local-patch descriptor based on efficient match kernels from pixel gradients.

Position

Revisiting Oxford and Paris: Large-Scale Image Retrieval Benchmarking

2 code implementations CVPR 2018 Filip Radenović, Ahmet Iscen, Giorgos Tolias, Yannis Avrithis, Ondřej Chum

In particular, annotation errors, the size of the dataset, and the level of challenge are addressed: new annotation for both datasets is created with an extra attention to the reliability of the ground truth.

Benchmarking Image Retrieval +1

Fine-tuning CNN Image Retrieval with No Human Annotation

14 code implementations3 Nov 2017 Filip Radenović, Giorgos Tolias, Ondřej Chum

We show that both hard-positive and hard-negative examples, selected by exploiting the geometry and the camera positions available from the 3D models, enhance the performance of particular-object retrieval.

Image Retrieval Retrieval

Asymmetric Feature Maps with Application to Sketch Based Retrieval

no code implementations CVPR 2017 Giorgos Tolias, Ondřej Chum

To demonstrate the advantages of the AFM method, we derive a short vector image representation that, due to asymmetric feature maps, supports efficient scale and translation invariant sketch-based image retrieval.

Retrieval Sketch-Based Image Retrieval +1

CNN Image Retrieval Learns from BoW: Unsupervised Fine-Tuning with Hard Examples

5 code implementations8 Apr 2016 Filip Radenović, Giorgos Tolias, Ondřej Chum

Convolutional Neural Networks (CNNs) achieve state-of-the-art performance in many computer vision tasks.

Image Retrieval Retrieval

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