Wyniki wyszukiwania - Biblioteka Nauki

1

A new multi-path scheme for adaptive computation-aware motion estimation

100%

Jakubowski M. , Pastuszak G.

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tom Vol. 15, No. 2

118-124

EN

Ability to work in a computation-limited and computation-variant environment described as "computational awareness" is a desirable feature of a real-time motion estimation system. In this paper, a new multi-path computation-aware algorithm is proposed. One-pass scheme, presented in the prior work by Chen et al., considers only one candidate point which is the median of neighbouring motion vectors (MVs). However, when computational resources are abundant, it is possible to investigate more search paths around points from the prediction set and get a significant improvement both in terms of quality and utilization of available search points (SPs). There are also other enhancements introduced regarding the way of selection of the starting SP and the search strategy, and allocation of resources, which leads to higher PSNR and a better utilization of computational resources.

2

GOP Structure Adaptable to the Location of Shot Cuts

75%

Krulikovská L. , Polec J.

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tom Vol. 58, No. 2

129-134

EN

In this paper we present a novel two stage algorithm for improving video coding efficiency. The proposed method combines video cut detection and adaptive GOP structure. At first, we have proposed a new technique of frames' comparison for the shot cut detection. The majority of existing methods compare pairs of successive frames. We compare actual frame with its motion estimated prediction. We also present adaptive threshold. The efficiency of novel technique for video cut detection was confirmed through experiment and compared to the commonly used ones in the terms of recall and precision. The next step is to situate I frames to the positions of detected cuts during the process of video encoding. Finally the proposed method is verified by simulations and the obtained results are compared with fixed GOP structures of sizes 4, 8, 12, 16, 32, 64, 128 and GOP structure with length of entire video. Proposed method achieved the gain in bit rate from 15,33% to 50,59%, while not degrading PSNR in comparison to simulated fixed GOP structures.

3

Robust region merging for motion based segmentation using the Kolmogorov-Smirnov test

75%

Broekhoven M. , Hupkens T. , Hendriks E. , Patras I.

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tom Vol. 6, no 3-4

27-34

EN

This paper addresses the problem of segmenting image sequences into moving objects. The proposed method uses a bottom-up approach and uses an indirect method to estimate the motion parameters of the initial regions. These regions have been created using the watershed algorithm. The motion of the regions have been modelled by a four parameter affine model and have been estimated by using a robust method, which diminishes the influence of wrongly estimated displacement or optical flow vectors (outliers). The similarity measure between two adjacent regions is computed through a non-parametric statistical test (the Kolmogorov-Smirnov test) as proposed by Moscheni [1] with some important modifications. The algorithm iterates between a motion estimation step and a region merging step until some stopping criterion has been reached. The results indicate that the method is well suited to obtain a correct segmentation of real image sequences.

4

A video coding technique with BTC-PF method for fast decoding

75%

Dhara B. C. , Saha S. K. , Chanda B.

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tom Vol. 16, no 1-2

29-42

EN

We have presented a video coding system that enables fast decoding and there by caters the need of the real time applications like video on demand, video play back, video retrieval. Proposed methodology relies on a fast motion estimation scheme, hierarchical BTC-PF based redundancy removal technique and finally it uses entropy decoding. As the encoding method is free from transformation and quantization steps, the decoding becomes faster. It also maintains the quality within the acceptable limit and improves bpp.

5

Model algorytmiczny komputerowego systemu nawigacyjnego do wspomagania zabiegów igłowej biopsji przezoskrzelowej metodą wirtualnej bronchoskopii.

63%

Zieliński T. , Duplaga M. , Bułat J. , Duda K. , Socha M. , Turcza P.

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tom R. 53, nr 3

87-94

PL

W artykule przedstawiono opracowany model algorytmiczny systemu do wspomagania pozycjonowania końcówki bronchofiberoskopu, względem organów anatomicznych człowieka, podczas zabiegu igłowej, przezoskrzelowej biopsji aspiracyjnej. Jego zadaniem jest ułatwienie lekarzowi pobrania do analizy próbki tkanek konkretnego, zbyt dużego węzła chłonnego (znalezionego metodą tomografii komputerowej), drogą jego nakłucia od strony wnętrza drzewa oskrzelowego. Podstawą działania systemu jest dopasowywanie do siebie dwóch obrazów: rzeczywistego, pochodzącego z kamery endoskopowej bronchofiberoskopu, oraz wirtualnego, syntezowanego na podstawie danych tomograficznych pacjenta. W artykule opisano poszczególne bloki składowe algorytmu nawigacji oraz przeprowadzono dyskusję nad możliwością jego implementacji w czasie rzeczywistym.

EN

In the paper developed algorithmic model of a computer system for bronchofiberoscope positioning (in respect to human body organs) during transbronchial needle-aspiration biopsy is described. Its goal is to help a doctor to take a probe of a pathologically enlarged lesion (found during computed tomography examination) by means of needle aspiration performed from bronchial tree interior. The system exploits an idea of registration of two images: the real one, coming from endoscope camera, and, the virtual one, synthesized on the base of computed tomography data. Main building blocks of the navigation algorithm are presented and possibility of its future real-time implementation is discussed.

6

Implementacja kodeka standardu MPEG-2 w układach FPGA

63%

Dąbrowska-Boruch A. , Wiatr K.

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2008

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tom T. 12, z. 3

615-623

PL

Metoda kompresji zastosowana w standardzie MPEG-2 jest kombinacją innych standardów, a mianowicie: JPEG oraz H.261. Ponieważ sygnał wizyjny jest w tym przypadku sekwencją nieruchomych obrazów, możliwe jest zastosowanie technik kompresji, podobnych jak w przypadku standardu JPEG. W artykule zostały przedstawione wyniki implementacji toru przetwarzania sygnału wizyjnego zgodnego ze specyfikacją standardu ISO/IEC 13818 w układzie XC2VP100(-6)FF1704 firmy Xilinx.

EN

The compression method applied in MPEG-2 standard is a combination of different standards, namely JPEG and H.261. There is possible to use similar compression techniques how in case of the JPEG standard, because the video signal is a sequence of still pictures. Paper presents implementation results of video signal processing path compatible with ISO/IEC 13818 standard specification in XC2VP100(-6)FF1704 Xilinx chip.

7

On the Representation of Human Motions and Distance-based Retargeting

51%

Hengeveld S. , Mucherino A.

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2021

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tom Vol. 25

181--189

EN

Distance-based motion adaptation leads to the formulation of a dynamical Distance Geometry Problem (dynDGP) where the involved distances simultaneously represent the morphology of the animated character, as well as a possible motion. The explicit use of inter-joint distances allows us to easily verify the presence of joint contacts, which one generally wishes to preserve when adapting a given motion to characters having a different morphology. In this work, we focus our attention on suitable representations of human-like animated characters, and study the advantages (and disadvantages) in using some of them. In the initial works on distance-based motion adaptation, a 3ndimensional vector was employed for representing the positions of the n joints of the character at a given frame. Here, we investigate the use of another, very popular in computer graphics, representation that basically replaces every joint position in the three-dimensional space with a set of three sorted Euler angles. We show that the latter can in fact be useful for avoiding some of the artifacts that were observed in previous computational experiments, but we argue that this Euler-angle representation, from a motion adaptation point of view, does not seem to be the optimal one. By paying particular attention to the degrees of freedom of the studied representations, it turns out that a novel character representation, inspired by representations used in structural biology for molecules, may allow us to reduce the character degrees of freedom to their minimal value. As a result, statistical analysis on human motion databases, where the motions are given with this new representation, can potentially provide important insights on human motions. This study is an initial step towards the identification of a full set of constraints capable of ensuring that unnatural postures for humans cannot be created while tackling motion adaptation problems.