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Author  |
Jaime Moreno; Xavier Otazu | ||||
| Title | Image compression algorithm based on Hilbert scanning of embedded quadTrees: an introduction of the Hi-SET coder | Type | Conference Article | ||
| Year | 2011 | Publication | IEEE International Conference on Multimedia and Expo | Abbreviated Journal | |
| Volume | Issue | Pages | 1-6 | ||
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| Abstract | In this work we present an effective and computationally simple algorithm for image compression based on Hilbert Scanning of Embedded quadTrees (Hi-SET). It allows to represent an image as an embedded bitstream along a fractal function. Embedding is an important feature of modern image compression algorithms, in this way Salomon in [1, pg. 614] cite that another feature and perhaps a unique one is the fact of achieving the best quality for the number of bits input by the decoder at any point during the decoding. Hi-SET possesses also this latter feature. Furthermore, the coder is based on a quadtree partition strategy, that applied to image transformation structures such as discrete cosine or wavelet transform allows to obtain an energy clustering both in frequency and space. The coding algorithm is composed of three general steps, using just a list of significant pixels. The implementation of the proposed coder is developed for gray-scale and color image compression. Hi-SET compressed images are, on average, 6.20dB better than the ones obtained by other compression techniques based on the Hilbert scanning. Moreover, Hi-SET improves the image quality in 1.39dB and 1.00dB in gray-scale and color compression, respectively, when compared with JPEG2000 coder. | ||||
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| ISSN | 1945-7871 | ISBN | 978-1-61284-348-3 | Medium | |
| Area | Expedition | Conference | ICME | ||
| Notes | CIC | Approved | no | ||
| Call Number | Admin @ si @ MoO2011a | Serial | 2176 | ||
| Permanent link to this record | |||||
| Author |
Jaime Moreno; Xavier Otazu | ||||
| Title | Image coder based on Hilbert scanning of embedded quadTrees | Type | Conference Article | ||
| Year | 2011 | Publication | Data Compression Conference | Abbreviated Journal | |
| Volume | Issue | Pages | 470-470 | ||
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| Abstract | In this work we present an effective and computationally simple algorithm for image compression based on Hilbert Scanning of Embedded quadTrees (Hi-SET). It allows to represent an image as an embedded bitstream along a fractal function. Embedding is an important feature of modern image compression algorithms, in this way Salomon in [1, pg. 614] cite that another feature and perhaps a unique one is the fact of achieving the best quality for the number of bits input by the decoder at any point during the decoding. Hi-SET possesses also this latter feature. Furthermore, the coder is based on a quadtree partition strategy, that applied to image transformation structures such as discrete cosine or wavelet transform allows to obtain an energy clustering both in frequency and space. The coding algorithm is composed of three general steps, using just a list of significant pixels. | ||||
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| Area | Expedition | Conference | DCC | ||
| Notes | CIC | Approved | no | ||
| Call Number | Admin @ si @ MoO2011b | Serial | 2177 | ||
| Permanent link to this record | |||||
| Author |
Jaime Moreno | ||||
| Title | Perceptual Criteria on Image Compresions | Type | Book Whole | ||
| Year | 2011 | Publication | PhD Thesis, Universitat Autonoma de Barcelona-CVC | Abbreviated Journal | |
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| Abstract | Nowadays, digital images are used in many areas in everyday life, but they tend to be big. This increases amount of information leads us to the problem of image data storage. For example, it is common to have a representation a color pixel as a 24-bit number, where the channels red, green, and blue employ 8 bits each. In consequence, this kind of color pixel can specify one of 224 ¼ 16:78 million colors. Therefore, an image at a resolution of 512 £ 512 that allocates 24 bits per pixel, occupies 786,432 bytes. That is why image compression is important. An important feature of image compression is that it can be lossy or lossless. A compressed image is acceptable provided these losses of image information are not perceived by the eye. It is possible to assume that a portion of this information is redundant. Lossless Image Compression is defined as to mathematically decode the same image which was encoded. In Lossy Image Compression needs to identify two features inside the image: the redundancy and the irrelevancy of information. Thus, lossy compression modifies the image data in such a way when they are encoded and decoded, the recovered image is similar enough to the original one. How similar is the recovered image in comparison to the original image is defined prior to the compression process, and it depends on the implementation to be performed. In lossy compression, current image compression schemes remove information considered irrelevant by using mathematical criteria. One of the problems of these schemes is that although the numerical quality of the compressed image is low, it shows a high visual image quality, e.g. it does not show a lot of visible artifacts. It is because these mathematical criteria, used to remove information, do not take into account if the viewed information is perceived by the Human Visual System. Therefore, the aim of an image compression scheme designed to obtain images that do not show artifacts although their numerical quality can be low, is to eliminate the information that is not visible by the Human Visual System. Hence, this Ph.D. thesis proposes to exploit the visual redundancy existing in an image by reducing those features that can be unperceivable for the Human Visual System. First, we define an image quality assessment, which is highly correlated with the psychophysical experiments performed by human observers. The proposed CwPSNR metrics weights the well-known PSNR by using a particular perceptual low level model of the Human Visual System, e.g. the Chromatic Induction Wavelet Model (CIWaM). Second, we propose an image compression algorithm (called Hi-SET), which exploits the high correlation and self-similarity of pixels in a given area or neighborhood by means of a fractal function. Hi-SET possesses the main features that modern image compressors have, that is, it is an embedded coder, which allows a progressive transmission. Third, we propose a perceptual quantizer (½SQ), which is a modification of the uniform scalar quantizer. The ½SQ is applied to a pixel set in a certain Wavelet sub-band, that is, a global quantization. Unlike this, the proposed modification allows to perform a local pixel-by-pixel forward and inverse quantization, introducing into this process a perceptual distortion which depends on the surround spatial information of the pixel. Combining ½SQ method with the Hi-SET image compressor, we define a perceptual image compressor, called ©SET. Finally, a coding method for Region of Interest areas is presented, ½GBbBShift, which perceptually weights pixels into these areas and maintains only the more important perceivable features in the rest of the image. Results presented in this report show that CwPSNR is the best-ranked image quality method when it is applied to the most common image compression distortions such as JPEG and JPEG2000. CwPSNR shows the best correlation with the judgement of human observers, which is based on the results of psychophysical experiments obtained for relevant image quality databases such as TID2008, LIVE, CSIQ and IVC. Furthermore, Hi-SET coder obtains better results both for compression ratios and perceptual image quality than the JPEG2000 coder and other coders that use a Hilbert Fractal for image compression. Hence, when the proposed perceptual quantization is introduced to Hi-SET coder, our compressor improves its numerical and perceptual e±ciency. When ½GBbBShift method applied to Hi-SET is compared against MaxShift method applied to the JPEG2000 standard and Hi-SET, the images coded by our ROI method get the best results when the overall image quality is estimated. Both the proposed perceptual quantization and the ½GBbBShift method are generalized algorithms that can be applied to other Wavelet based image compression algorithms such as JPEG2000, SPIHT or SPECK. | ||||
| Address | |||||
| Corporate Author | Thesis | Ph.D. thesis | |||
| Publisher | Ediciones Graficas Rey | Place of Publication | Editor | Xavier Otazu | |
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| ISSN | ISBN | 978-84-938351-3-2 | Medium | ||
| Area | Expedition | Conference | |||
| Notes | CIC | Approved | no | ||
| Call Number | Admin @ si @ Mor2011 | Serial | 1786 | ||
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| Author |
Jaime Lopez-Krahe; Josep Llados; Enric Marti | ||||
| Title | Architectural Floor Plan Analysis | Type | Report | ||
| Year | 2000 | Publication | CVonline | Abbreviated Journal | |
| Volume | Issue | Pages | |||
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| Address | Edimburg, UK | ||||
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| Publisher | University of Edinburgh | Place of Publication | Editor | Robert B. Fisher | |
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| ISSN | ISBN | Medium | online pdf | ||
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| Notes | DAG;IAM | Approved | no | ||
| Call Number | IAM @ iam @ LLM2000 | Serial | 1561 | ||
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| Author |
J.S. Cope; P.Remagnino; S.Mannan; Katerine Diaz; Francesc J. Ferri; P.Wilkin | ||||
| Title | Reverse Engineering Expert Visual Observations: From Fixations To The Learning Of Spatial Filters With A Neural-Gas Algorithm | Type | Journal Article | ||
| Year | 2013 | Publication | Expert Systems with Applications | Abbreviated Journal | EXWA |
| Volume | 40 | Issue | 17 | Pages | 6707-6712 |
| Keywords | Neural gas; Expert vision; Eye-tracking; Fixations | ||||
| Abstract | Human beings can become experts in performing specific vision tasks, for example, doctors analysing medical images, or botanists studying leaves. With sufficient knowledge and experience, people can become very efficient at such tasks. When attempting to perform these tasks with a machine vision system, it would be highly beneficial to be able to replicate the process which the expert undergoes. Advances in eye-tracking technology can provide data to allow us to discover the manner in which an expert studies an image. This paper presents a first step towards utilizing these data for computer vision purposes. A growing-neural-gas algorithm is used to learn a set of Gabor filters which give high responses to image regions which a human expert fixated on. These filters can then be used to identify regions in other images which are likely to be useful for a given vision task. The algorithm is evaluated by learning filters for locating specific areas of plant leaves. | ||||
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| ISSN | 0957-4174 | ISBN | Medium | ||
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| Notes | ADAS | Approved | no | ||
| Call Number | Admin @ si @ CRM2013 | Serial | 2438 | ||
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| Author |
J.R. Serra; S. Casadei; J.B. Subirana | ||||
| Title | Non-Cartesian Networks for Middle Level Vision. | Type | Miscellaneous | ||
| Year | 1995 | Publication | VI National Simposium on Pattern Recognition and image Analysis | Abbreviated Journal | |
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| Address | Cordoba | ||||
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| Notes | Approved | no | |||
| Call Number | Admin @ si @ SCS1995 | Serial | 232 | ||
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| Author |
J.R. Serra; J.B. Subirana | ||||
| Title | Adaptive non-cartesian networks for vision. | Type | Miscellaneous | ||
| Year | 1997 | Publication | IX International Conference on Image Analysis and Processing. | Abbreviated Journal | |
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| Address | Florence | ||||
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| Notes | Approved | no | |||
| Call Number | Admin @ si @ SeS1997 | Serial | 212 | ||
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| Author |
J.R. Serra; J.B. Subirana | ||||
| Title | Extraccion de estructuras interesantes en imagenes | Type | Report | ||
| Year | 1996 | Publication | CVC Tecnical Report #14 | Abbreviated Journal | |
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| Address | CVC (UAB) | ||||
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| Notes | Approved | no | |||
| Call Number | Admin @ si @ SeS1996c | Serial | 216 | ||
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| Author |
J.R. Serra; J.B. Subirana | ||||
| Title | Perceptual Grouping on Texture Images Using Non-Cartesian Networks | Type | Journal | ||
| Year | 1996 | Publication | IEEE International Conference on Pattern Recognition. Vol B, pp. 462–466 | Abbreviated Journal | |
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| Notes | Approved | no | |||
| Call Number | Admin @ si @ SeS1996a | Serial | 217 | ||
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| Author |
J.R. Serra; J.B. Subirana | ||||
| Title | Perceptual grouping on texture images using non-cartesian networks | Type | Report | ||
| Year | 1996 | Publication | CVC Technical Report #11 | Abbreviated Journal | |
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| Address | CVC (UAB) | ||||
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| Notes | Approved | no | |||
| Call Number | Admin @ si @ SeS1996b | Serial | 218 | ||
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| Author |
J.R. Serra; A. Martinez; Jordi Vitria; J.B. Subirana | ||||
| Title | Iconic Representation to Image Retrieval. | Type | Miscellaneous | ||
| Year | 1997 | Publication | Jornades d'Intel.ligència Artificial: Noves Tendències (JIA'97) | Abbreviated Journal | |
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| Address | Lleida | ||||
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| Notes | DOC;OR;MV | Approved | no | ||
| Call Number | BCNPCL @ bcnpcl @ SMV1997 | Serial | 55 | ||
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| Author |
J.Poujol; Cristhian A. Aguilera-Carrasco; E.Danos; Boris X. Vintimilla; Ricardo Toledo; Angel Sappa | ||||
| Title | Visible-Thermal Fusion based Monocular Visual Odometry | Type | Conference Article | ||
| Year | 2015 | Publication | 2nd Iberian Robotics Conference ROBOT2015 | Abbreviated Journal | |
| Volume | 417 | Issue | Pages | 517-528 | |
| Keywords | Monocular Visual Odometry; LWIR-RGB cross-spectral Imaging; Image Fusion. | ||||
| Abstract | The manuscript evaluates the performance of a monocular visual odometry approach when images from different spectra are considered, both independently and fused. The objective behind this evaluation is to analyze if classical approaches can be improved when the given images, which are from different spectra, are fused and represented in new domains. The images in these new domains should have some of the following properties: i) more robust to noisy data; ii) less sensitive to changes (e.g., lighting); iii) more rich in descriptive information, among other. In particular in the current work two different image fusion strategies are considered. Firstly, images from the visible and thermal spectrum are fused using a Discrete Wavelet Transform (DWT) approach. Secondly, a monochrome threshold strategy is considered. The obtained
representations are evaluated under a visual odometry framework, highlighting their advantages and disadvantages, using different urban and semi-urban scenarios. Comparisons with both monocular-visible spectrum and monocular-infrared spectrum, are also provided showing the validity of the proposed approach. |
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| Address | Lisboa; Portugal; November 2015 | ||||
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| Publisher | Springer International Publishing | Place of Publication | Editor | ||
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| ISSN | 2194-5357 | ISBN | 978-3-319-27145-3 | Medium | |
| Area | Expedition | Conference | ROBOT | ||
| Notes | ADAS; 600.076; 600.086 | Approved | no | ||
| Call Number | Admin @ si @ PAD2015 | Serial | 2663 | ||
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| Author |
J.M. Sanchez; X. Binefa; Jordi Vitria; Petia Radeva | ||||
| Title | Local Analysis for Scene Break Detection Applied to TV Commercials Recognition. | Type | Miscellaneous | ||
| Year | 1999 | Publication | Visual information and information systems, 237–244, Springer– Verlag. | Abbreviated Journal | |
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| Notes | OR;MILAB;MV | Approved | no | ||
| Call Number | BCNPCL @ bcnpcl @ SBV1999 | Serial | 27 | ||
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| Author |
J.M. Sanchez; X. Binefa; Jordi Vitria | ||||
| Title | Shot Partitioning Based Recognition of Tv Commercials | Type | Journal | ||
| Year | 2002 | Publication | Multimedia Tools and Applications, 18: 233–247, Kluwer Academic Publishers (IF: 0.421) | Abbreviated Journal | |
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| Notes | OR;MV | Approved | no | ||
| Call Number | BCNPCL @ bcnpcl @ SBV2002 | Serial | 274 | ||
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| Author |
J.M. Sanchez; X. Binefa; J.R. Kender | ||||
| Title | Coupled Markox Chains for Video Contents Characterization. | Type | Miscellaneous | ||
| Year | 2002 | Publication | Proceeding of the International Conference on Pattern Recognition ICPR 2002 | Abbreviated Journal | |
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| Notes | Approved | no | |||
| Call Number | Admin @ si @ SBK2002a | Serial | 298 | ||
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