A proposal for dependent optimization in scalabale region-based coding systems

We address in this paper the problem of optimal coding in the framework of region-based video coding systems, with a special stress on content-based functionalities. We present a coding system that can provide scaled layers (using PSNR or temporal content-based scalability) such that each one has an optimal partition with optimal bit allocation among the resulting regions. This coding system is based on a dependent optimization algorithm that can provide joint optimality for a group of layers or a group of frames.Peer ReviewedPostprint (published version

A morphological approach for segmentation and tracking of human faces

A new technique for segmenting and tracking human faces in video sequences is presented. The technique relies on morphological tools such as using connected operators to extract the connected component that more likely belongs to a face, and partition projection to track this component through the sequence. A binary partition tree (BPT) is used to implement the connected operator. The BPT is constructed based on the chrominance criteria and its nodes are analyzed so that the selected node maximizes an estimation of the likelihood of being part of a face. The tracking is performed using a partition projection approach. Images are divided into face and non-face parts, which are tracked through the sequence. The technique has been successfully assessed using several test sequences from the MPEG-4 (raw format) and the MPEG-7 databases (MPEG-1 format).Peer ReviewedPostprint (published version

Recursive image sequence segmentation by hierarchical models

This paper addresses the problem of image sequence segmentation. A technique using a sequence model based on compound random fields is presented. This technique is recursive in the sense that frames are processed in the same cadency as they are produced. New regions appearing in the sequence are detected by a morphological procedure.Peer ReviewedPostprint (published version

A contour matching approach for accurate NOAA-AVHRR image navigation

Although different methods for NOAA AVHRR image navigation have already been established, the multitemporal and multi-satellite character of most studies requires automatic and accurate methods for navigation of satellite images. In the proposed method, a simple Kepplerian orbital model for the NOAA satellites is considered as reference model, and mean orbital elements are given as input to the model from ephemeris data. In order to correct the errors caused by these simplifications, errors resulting from inaccuracies in the positioning of the satellite and failures in the satellite internal clock, an automatic global contour matching approach has been adopted. First, the sensed image is preprocessed to obtain a gradient energy map of the reliable areas (sea-land contours) using a cloud detection algorithm and a morphological gradient operator. An initial estimation of the reliable contour positions is automatically obtained. The final positions of the contours are obtained by means of an iterative local minimization procedure that allows a contour to converge on an area of high image energy (edge). Global transformation parameters are estimated based on the initial and final positions of all reliable contour points. Finally, the performance of this approach is assessed using NOAA 14 AVHRR images from different geographic areas.Postprint (published version

Coagulation time detection by means of a real-time image processing

Several techniques for semi-automatic or automatic detection of coagulation time in blood or in plasma analysis are available in the literature. However, these techniques are either complex and demand for specialized equipment, or allow the analysis of very few samples in parallel. In this paper a new system based on computer vision is presented. An easy image processing algorithm has been developed, which leads to an accurate estimation of the coagulation time of several samples in parallel. The estimation can be performed in real time using transputer architecture supported by a PC.Peer ReviewedPostprint (published version

Segmentation-based video coding:temporals links

This paper analyzes the main elements that a segmentation-based video coding approach should be based on so that it can address coding efficiency and content-based functionalities. Such elements can be defined as temporal linking and rate control. The basic features of such elements are discussed and, in both cases, a specific implementation is proposed.Peer ReviewedPostprint (published version

Supervised evaluation of image segmentation and object proposal techniques

This paper tackles the supervised evaluation of image segmentation and object proposal algorithms. It surveys, structures, and deduplicates the measures used to compare both segmentation results and object proposals with a ground truth database; and proposes a new measure: the precision-recall for objects and parts. To compare the quality of these measures, eight state-of-the-art object proposal techniques are analyzed and two quantitative meta-measures involving nine state of the art segmentation methods are presented. The meta-measures consist in assuming some plausible hypotheses about the results and assessing how well each measure reflects these hypotheses. As a conclusion of the performed experiments, this paper proposes the tandem of precision-recall curves for boundaries and for objects-and-parts as the tool of choice for the supervised evaluation of image segmentation. We make the datasets and code of all the measures publicly available.Peer ReviewedPostprint (author's final draft

System architecture for indexing regions in keyframes

This paper describes the design of an indexing system for a video database. The system uses region-based manual an- notations of keyframes to create models to automatically annotate new keyframes also at the region level. The pre- sented architecture includes user interfaces for training and querying the system, internal databases to manage ingested content and modelled semantic classes, as well as communi- cation interfaces to allow the system interconnection. The scheme is designed to work as a plug-in to an external Mul- timedia Asset Management (MAM) system.Postprint (published version

Hierarchical fusion of color and depth information at partition level by cooperative region merging

A high level scheme for information fusion to create hierarchical region-based image representations based on a region merging process is presented. The strategy is based on an iterative evolution where the different merging criteria work independently and cooperate at the partition level to obtain a further consensus that increases the reliability of the resulting partitions. This cooperative scheme is applied to the creation of hierarchical region-based representations of the image based on color and depth information. The proposed technique is compared with approaches using only one source of information or linear combinations of both, in datasets with ground truth as well as estimated disparity information.Postprint (published version

La Millor Metodologia Docent

En aquesta xerrada defensaré la que jo considero que és la millor metodologia docent i com es pot aplicar. Intentaré argumentar els diferents punts amb exemples personals o propers per tal de poder donar referències clares de motivació i aplicabilitat.Peer Reviewe