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Image Processing, IET

Issue 1 • Date Feb. 2008

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Displaying Results 1 - 4 of 4
  • Video texture modelling and synthesis using fractal processes

    Page(s): 1 - 17
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1244 KB)  

    The authors propose a new approach for the synthesis of natural video textures using a fractal- based approach. Specifically, a video texture is modelled according to the three-dimensional (3D) extended self-similar (ESS) model introduced, which generalises the fractional Brownian motion process. The analysis of original video textures is based on the estimation of the autocorrelation functions (ACFs) of the textures' increments. The 3D-ESS model is then used to synthesise a process whose increments have the same ACFs of the given prototype. The synthesis is accomplished by generalising to the 3D case the incremental Fourier synthesis algorithm. Experimental results for the analysis and synthesis of natural video textures are eventually provided. View full abstract»

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  • Fast centre-surround contrast modification

    Page(s): 19 - 34
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1099 KB)  

    A new algorithm for fast contrast modification of standard dynamic range (SDR) images (8 bits/ channel) is presented. Its thrust is to enhance the contrast in the under-/over-exposed regions of SDR images, caused by the low dynamic range of the capturing device. It is motivated by the attributes of the shunting centre-surround cells of the human visual system. The main advantage of the proposed algorithm is its O(N) complexity which results in very fast execution, even when executed on a conventional personal computer (0.2 s/frame for a 640 times 480 pixel resolution on a 3 GHz Pentium 4). Thus, it moderately increases the computational burden if it is used as a pre-processing stage for other image processing algorithms. The proposed method is compared with other established algorithms, which can enhance the contrast in the under-/over-exposed regions of SDR images: the multi-scale Retinex with colour rendition, the McCann Retinex (McCann99), the rational mapping function and the automatic colour equalisation. The results obtained by this comparison indicate that the proposed algorithm exhibits at least comparable results in contrast modification tasks to the other algorithms, in significantly reduced execution times. View full abstract»

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  • Discrete image modelling for piecewise constant segmentation by artificial neural networks

    Page(s): 37 - 47
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (621 KB)  

    The problem of an image best approximation within the class of piecewise constant functions is considered. This allows a simpler data representation with a lower number of grey levels while retaining all information relevant to the particular application considered. The approximant can be found by solving a segmentation problem. The search for a solution is solved efficiently by training an artificial neural network (ANN) on a suitable set of templates by a standard procedure. The samples of the training alphabet fit the signal's local behaviour in the homogeneous image subregions and in the regions crossed by the edges. Therefore the original image domain is partitioned into disjoint 2D intervals (tiling), and for each one of them, the network selects the alphabet element closest to the corresponding image component. The main motivation of this work consists in devising a methodology suitable for real-time applications; indeed, the ANN tool is attractive for a hardware implementation. View full abstract»

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  • Optical coherence tomography used for security and fingerprint-sensing applications

    Page(s): 48 - 58
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1191 KB)  

    Optical coherence tomography (OCT) is an emerging technology for high-resolution cross-sectional imaging of three-dimensional structures. In the past, OCT systems have been used mainly for medical applications, especially ophthalmological diagnostics. As the OCT system is capable of exploring the internal features of an object, the authors apply OCT technology to document security and fingerprint-based biometrics by directly retrieving the two-dimensional information form of a multiple-layer information carrier and internal human body objects. Since a typical depth-resolution of an OCT system is of micrometre scale, an information carrier having a volume of 20 mm times 20 mm times 2 mm could contain 200 mega-pixel images. On other hand, the technologies used in conventional biometrics can be easily fooled and tampered with by using artificial dummies, because these ID features are extracted only from the surface of the skin. Hence the use of OCT to explore the internal biometrics becomes increasingly important. View full abstract»

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Aims & Scope

The range of topics covered by IET Image Processing includes areas related to the generation, processing and communication of visual information.

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