Mátyás Brendel

Overview of the ImageCLEF 2007 Object Retrieval Task

We describe the object retrieval task of ImageCLEF 2007, give an overview of the methods of the participating groups, and present and discuss the results. The task was based on the widely used PASCAL object recognition data to train object recognition methods and on the IAPR TC-12 benchmark dataset from which images of objects of the ten different classes bicycles, buses, cars, motorbikes, cats, cows, dogs, horses, sheep, and persons had to be retrieved. Seven international groups participated using a wide variety of methods. The results of the evaluation show that the task was very challenging and that different methods for relevance assessment can have a strong influence on the results of an evaluation.

Adaptive image sensing and enhancement using the cellular neural network universal machine

As an attempt to introduce interactive, content-dependent adaptive (ICDA) image processing, a simple but powerful active image sensing and two image enhancement methods are introduced via adaptive CNN-UM sensor-computers. Thus, the method ICDA can be used for adaptive control of image sensing and for subsequent on-line or off-line image enhancement as well. The algorithms use both intensity and contrast content. The image sensing technology can be realized with the current CNN-UM chip. Our first image enhancement method is also executable on this chip, but it is more suitable for the adaptive cellular neural network universal machine (ACNN-UM) architecture. Some results of simulator and chip experiments and an adaptive extended cell are presented. Our second, dynamical image enhancement method is planned to be executable on a multi-layer, complex cell CNN architecture. In (Proceedings of the 6th IEEE International Workshop on Cellular Neural Networks and their Applications (CNNA-2000) Catania, 2000; 213–217) 3-layer architecture is described which is capable of realizing the main part of the second enhancement method. The main issues of our paper are as follows: the novel outlook of the ICDA framework, three new methods for two key application areas of CNN-UM, the notion of ‘regional’ adaptive computing, the novelty of application of equilibrium-computing in the third method. However, the key novelty of our work is not just a new method and a new realization: by combining sensing and computing, dynamically and pixelwise, a new quality becomes practical. Copyright

Gradient Computation of Continuous-Time Cellular Neural/Nonlinear Networks with Linear Templates via the CNN Universal Machine

Single-layer, continuous-time cellular neural/nonlinear networks (CNN) are considered with linear templates. The networks are programmed by the template-parameters. A fundamental question in template training or adaptation is the gradient computation or approximation of the error as a function of the template parameters. Exact equations are developed for computing the gradients. These equations are similar to the CNN network equations, i.e. they have the same neighborhood and connectivity as the original CNN network. It is shown that a CNN network, with a modified output function, can compute the gradients. Thus, fast on-line gradient computation is possible via the CNN Universal Machine, which allows on-line adaptation and training. The method for computing the gradient on-chip is investigated and demonstrated.

Multimodal Retrieval by Text---Segment Biclustering

We describe our approach to the ImageCLEFphoto 2007 task. The novelty of our method consists of biclustering image segments and annotation words. Given the query words, it is possible to select the image segment clusters that have strongest cooccurrence with the corresponding word clusters. These image segment clusters act as the selected segments relevant to a query. We rank text hits by our own tf.idf-based information retrieval system and image similarities by using a 20-dimensional vector describing the visual content of an image segment. Relevant image segments were selected by the biclustering procedure. Images were segmented by graph-based segmentation. We used neither query expansion nor relevance feedback; queries were generated automatically from the title and the description words. The later were weighted by 0.1.

SZTAKI @ ImageCLEF 2008: visual feature analysis in segmented images

We describe our image processing system used in the Image-CLEF 2008 Photo Retrieval and Visual Concept Detection tasks. Our method consists of image segmentation followed by feature generation over the segments based on color, shape and texture. In the paper we elaborate on the importance of choices in the segmentation procedure with emphasis on edge detection. We also measure the relative importance of the visual features as well as the right choice of the distance function. Finally, given a very large number of parameters in our image processing system, we give a method for parameter optimization by measuring how well the similarity measures separate sample images of the same topic from those of different topics.