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Acoustics, Speech, and Signal Processing (ICASSP), 2002 IEEE International Conference on

Date 13-17 May 2002

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  • [Title page]

    Publication Year: 2002 , Page(s): i - civ
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  • Dynamic tomography with curve evolution methods

    Publication Year: 2002 , Page(s): IV-3229 - IV-3232
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (537 KB) |  | HTML iconHTML  

    In this paper, we propose a curve evolution method for dynamic tomography. We jointly estimate both object boundaries and intensity dynamics using all the data. The image intensity is assumed piecewise constant and the activity in each region is modeled as a parameterized dynamic process. The boundaries of objects are modeled as a series of curves. The boundaries and dynamics are estimated jointly through a curve evolution process. This curve evolution process is implemented with level set methods, which can handle topology changes easily. View full abstract»

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  • Method of color interpolation in a single sensor color camera using green channel separation

    Publication Year: 2002 , Page(s): IV-3233 - IV-3236
    Cited by:  Papers (5)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (618 KB) |  | HTML iconHTML  

    This paper presents a color interpolation algorithm for a single sensor color camera. The proposed algorithm is especially designed to solve the problem of pixel crosstalk among the pixels of different color channels. Interchannel cross-talk gives rise to blocking effects on the interpolated green plane, and also spreading of false colors into detailed structures. The proposed algorithm separates the green channel into two planes, one highly correlated with the red channel and the other with the blue channel. These separate planes are used for red and blue channel interpolation. Experiments conducted on McBeth color chart and natural images have shown that the proposed algorithm can eliminate or suppress blocking and color artifacts to produce better quality images. View full abstract»

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  • A least squares approach for the joint domain and range registration of images

    Publication Year: 2002 , Page(s): IV-3237 - IV-3240
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (591 KB) |  | HTML iconHTML  

    An approach for jointly registering images in domain and range using a least squares formalism is presented. This joint approach is in contrast to almost all current registration methods that only register images with respect to their domains and neglect accounting for exposure differences between images. The inclusion of range into the registration process is accomplished by approximating the camera's nonlinear comparametric function with a piecewise linear one. This results in a computationally attractive least squares approach to an otherwise inherently nonlinear optimization problem. The effectiveness of this approach is illustrated. View full abstract»

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  • An efficient algorithm for the extraction of a Euclidean skeleton

    Publication Year: 2002 , Page(s): IV-3241 - IV-3244
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (767 KB) |  | HTML iconHTML  

    The skeleton is essential for general shape representation but the discrete representation of an image presents a lot of problems that may influence the process of skeleton extraction. Some of the methods are memory-intensive and computationally intensive, and require a complex data structure. In this paper, we propose a fast, efficient and accurate skeletonization method for the extraction of a well-connected Euclidean skeleton based on a signed sequential Euclidean distance map. A connectivity criterion that can be used to determine whether a given pixel inside an object is a skeleton point is proposed. The criterion is based on a set of points along the object boundary, which are the nearest contour points to the pixel under consideration and its 8 neighbors. The extracted skeleton is of single-pixel width without requiring a linking algorithm or iteration process. Experiments show that the runtime of our algorithm is faster than. those of using the distance transformation and is linearly proportional to the number of pixels of an image. View full abstract»

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  • A sensitivity measure for image reconstruction from irregular 2-D DTFT samples

    Publication Year: 2002 , Page(s): IV-3245 - IV-3248
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (557 KB) |  | HTML iconHTML  

    The problem of reconstructing an image from irregular samples of its 2-D DTFT arises in synthetic aperture radar (SAR), magnetic resonance imaging (MRI), limited angle tomography, and 2-D filter design. Since there is no 2-D Lagrange interpolation, sufficient conditions for the uniqueness and conditioning of the reconstruction problem are both not apparent. The Good-Thomas FFT is used to unwrap the 2-D problem into a 1-D problem, from which uniqueness results and, more importantly, insights into the problem conditioning are available. We propose the variance of distances between adjacent frequency locations as a sensitivity measure, which aids in determining a well-conditioned configuration of frequency values. The sensitivity measure is analyzed on its accuracy of estimating the conditioning and on its computational speed. The image is then reconstructed by solving the problem using the conjugate gradient method. View full abstract»

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  • Robustness of 3-D maximum likelihood reconstructions of viruses from cryo electron microscope images

    Publication Year: 2002 , Page(s): IV-3249 - IV-3252
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (787 KB) |  | HTML iconHTML  

    A statistical method for computing 3-D reconstructions of virus particles from cryo electron microscope images and minimal prior information-particle symmetry and radii-is described and demonstrated numerically focusing on the robustness of the approach. View full abstract»

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  • Embedded image compression based on wavelet pixel classification and sorting

    Publication Year: 2002 , Page(s): IV-3253 - IV-3256
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (694 KB) |  | HTML iconHTML  

    A new embedded image compression algorithm is proposed, based on progressive Pixel Classification And Sorting (PCAS) in wavelet domain. To exploit the intraband and interband correlation in wavelet domain, EZW [1] and SPIHT [2] implicitly classify wavelet pixels as zerotree pixels or not, while MRWD[3], SLCCA[4], and EBCOT[5] implicitly classify wavelet pixels as neighbors of significant pixels or not. In this paper, the wavelet pixels to be encoded are explicitly and finely classified based on their predicted probabilities, which is more sophisticated and effective. Furthermore, wavelet pixel sorting is introduced to help improve rate-distortion performance within each bit-plane coding. The technique of pixel classification and sorting is simple, yet effective to produce the image code with excellent compression performance. In addition, our algorithm provides both SNR and resolution scalability. View full abstract»

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  • Robust image transmission using variable QoS joint source-modulation coding

    Publication Year: 2002 , Page(s): IV-3257 - IV-3260
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (810 KB) |  | HTML iconHTML  

    In this paper, we present an optimal, low-complexity method of transmitting digitally compressed imagery through interference-dominated and frequency-selective fading channels. The proposed method combines a wavelet-based image coder that employs phase scrambling and variable quality-of-service (VQoS) trellis-coded quantization (TCQ), and VQoS multi carrier (MC) power allocation across the channel. Optimal image quality is achieved through a joint iterative process between the image coder and MC allocation algorithm. Using our VQoS allocation method, we show that the image quality can be improved significantly, as compared to an approach that uses an arbitrary fixed joint QoS-modulation allocation across the channel. Further, this improvement extends to a variety of channels, including those that exhibit jamming interference and frequency-selective fading. The method is also shown to be computationally efficient. View full abstract»

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  • A distributed source coding technique for highly correlated images using turbo-codes

    Publication Year: 2002 , Page(s): IV-3261 - IV-3264
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (455 KB) |  | HTML iconHTML  

    According to the Slepian-Wolf theorem [1], the output of two correlated sources can be compressed to the same extent without loss, no matter if they communicate with each other or not, provided that the decompression takes place at a common decoder having both compressed outputs available. In this paper, as an application of the Slepian-Wolf theorem, an advanced distributed source coding scheme for correlated images is presented. Assuming that the correlated image is a noisy version of the original, the scheme involves modulo encoding of the pixel values and encoding (compression) of the resulting symbols with binary and nonbinary turbo-codes, so that rate savings are achieved practically without loss. View full abstract»

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  • An encoder-only texture replacement method for effective compression of entertainment movie sequences

    Publication Year: 2002 , Page(s): IV-3265 - IV-3268
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (775 KB) |  | HTML iconHTML  

    In this paper, we propose a method for texture replacement in video sequences at the encoder. Our method consists of removal of texture from selected regions of the original frames, analysis of the removed texture, synthesis of new texture, and mapping of the new texture back onto the segmented regions. Our proposed method yields significantly reduced bit rates of the compressed video sequences with the texture replaced as compared to those of the original sequences. Moreover, the video sequences with texture replacement are visually similar to the original sequences. Even more, our decoder-independent method is cost effective. View full abstract»

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  • Improving coding efficiency in grid-based hybrid video coding schemes

    Publication Year: 2002 , Page(s): IV-3269 - IV-3272
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (868 KB) |  | HTML iconHTML  

    In the past many grid-based video coding schemes using image warping p17ediction have been proposed. The advantage of grid-based motion compensation is its ability to model non-translational motion. Disadvantages are the interdependency of motion vectors which require more complex motion estimation strategies and its restricted ability to model motion boundaries. In this paper different solutions, to cope with the latter deficiency are presented and compared with respect to coding efficiency. In particular, three adaptive modes for handling motion discontinuities and a block-adaptive loop filtering are presented. It is shown that these are key components for achieving a high coding gain in grid-based hybrid coding. Introducing these features into a wavelet-based video coder leads to a coding gain of up to 2,5 dB compared to ITU H263 + and MPEG-4. View full abstract»

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  • Wavelet-based multiresolution motion estimation through median filtering

    Publication Year: 2002 , Page(s): IV-3273 - IV-3276
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (503 KB) |  | HTML iconHTML  

    In this paper, a non-causal median filtering method is proposed to predict the motion vectors across the wavelet subbands of a video frame for multiresolution motion estimation. This median filtering method effectively overcomes the problem of propagation of false motion vectors that exists in the conventional multiresolution motion estimation schemes. A significant feature of the proposed technique is that it imposes no demand for additional bandwidth. Simulation studies show that this median filtering-based multiresolution motion; estimation technique effectively improves the motion prediction performance. It is further shown that this performance improvement is achieved with little increase in the computational complexity. View full abstract»

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  • A design method of invertible de-interlacer with sampling density preservation

    Publication Year: 2002 , Page(s): IV-3277 - IV-3280
    Cited by:  Papers (1)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB) |  | HTML iconHTML  

    A new class of de-interlacing is developed for intra-frame-based motion picture coding such as Motion-JPEG2000. The proposed technique has two features: the sampling density preservation and the invertibility. Thus, the amount of de-interlaced pictures is not increased and the original pictures can perfectly be reconstructed. This technique is regarded as a generalization of the conventional field interleaving. The significance is, verified by showing some design examples and simulation results, The proposed technique is also shown to cause less comb-shape artifacts than the conventional one. The intra-field-based case is also discussed. View full abstract»

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  • Robust and edge-preserving video error concealment by coarse-to-fine block replenishment

    Publication Year: 2002 , Page(s): IV-3281 - IV-3284
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (846 KB) |  | HTML iconHTML  

    In this paper we propose a novel error concealment algorithm for video transmission over wireless networks potentially subject to packet erasures. In particular, we develop a technique for the replenishment of missing macroblocks, which aims at minimizing the impact of the lost data on the resulting video with respect to the human visual system. The proposed algorithm operates three reconstruction stages at different scales, by first recovering smooth large-scale patterns, then large-scale structures, and finally local edges in the lost macroblock. Experimental results show that the proposed algorithm achieves improved visual quality of the reconstructed frames with respect to other state-of-the-art techniques, as well as better PSNR results. View full abstract»

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  • Deblocking of block-DCT compressed images using deblocking frames of variable size

    Publication Year: 2002 , Page(s): IV-3285 - IV-3288
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (969 KB) |  | HTML iconHTML  

    A new algorithm for the removal of blocking artifacts in block-DCT compressed images and video sequences is proposed in this paper. The algorithm uses deblocking frames of variable size (DFOVS). A deblocking frame is a square of pixels which overlaps image blocks. Deblocking is achieved by applying weighted summation on pixels quartets which reside in deblocking frames. The pixels in a quartet are symmetrically aligned with respect to block boundaries. The weights are determined according to a special 2-D function and a predefined factor, we refer to as a grade. A pixel's grade is determined according to the amount of details in its neighborhood. Deblocking of monotone areas is achieved by iteratively applying deblocking frames of decreasing sizes on such areas. This new algorithm produces very good subjective results and PSNR results which are competitive relative to available state-of-the-art methods. View full abstract»

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  • Connected operators based on reconstruction process for size and motion simplification

    Publication Year: 2002 , Page(s): IV-3289 - IV-3292
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (789 KB) |  | HTML iconHTML  

    This paper deals with connected operators based on reconstruction process. Connected operators are filtering tools that act on the connected components of the space where the image is constant, the so-called “flat zones”. Intuitively, connected operators can remove boundaries between flat zones but cannot add new boundaries nor shift existing contours. After reviewing the filtering strategy, new operators are proposed to perform size and motion simplification. In the case of size simplification, the proposed approach allows a better preservation the contrast of maxima or minima that have not been totally simplified by the filtering process. In the case of motion simplification, two applications are presented: motion detection for maxima/minima and sequence simplification to improve the coding efficiency of standard encoders. View full abstract»

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  • Signal-dependent noise removal in the undecimated wavelet domain

    Publication Year: 2002 , Page(s): IV-3293 - IV-3296
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (952 KB) |  | HTML iconHTML  

    In this paper, methods to denoise images corrupted by a signal-dependent additive distortion are proposed. The noise model is parametric to take into account different noise generation processes. Noise reduction is approached as a Wiener-like filtering performed in a shift-invariant wavelet domain by means of an adaptive rescaling of the coefficients of an undecimated decomposition. The scaling factor is computed by using the statistics estimated from the degraded image and the parameters of the noise model. The absence of decimation in the wavelet decomposition avoids the ringing impairments produced by critically-subsampled wavelet-based denoising. Experimental results demonstrate that excellent background smoothing as well as preservation of edge sharpness and texture can be obtained. View full abstract»

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  • Adaptive pre- and post-filtering for block based systems

    Publication Year: 2002 , Page(s): IV-3297 - IV-3300
    Cited by:  Papers (1)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (755 KB) |  | HTML iconHTML  

    This paper introduces an adaptive time-varying signal decomposition framework with perfect reconstruction via a combination of adaptive time-domain pre/post-processing and size-adaptive block DCTs. We explore different methods to produce time-varying basis functions and study various properties of the transition filter banks involved. Several criteria that could be used to select a certain set of basis functions are investigated. Promising coding gains over those of non-adaptive decompositions in an image coding setting are also presented. View full abstract»

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  • An improved spread spectrum technique for robust watermarking

    Publication Year: 2002 , Page(s): IV-3301 - IV-3304
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (691 KB) |  | HTML iconHTML  

    This paper introduces a new watermarking modulation technique, which we call improved spread spectrum (ISS). Unlike in traditional spread spectrum (SS), in ISS the carrier signal does not act as a noise source; leading significant performance gains. In typical examples, the gain of ISS over SS is 20 dB or more in signal-to-noise ratio or 20 orders of magnitude or more in error probability. The proposed method achieves roughly the same noise robustness gain as quantization index modulation (QIM). Nevertheless, while QIM is quite sensitive to amplitude variations, ISS is as robust in practice as traditional SS. View full abstract»

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  • Fragile speech watermarking based on exponential scale quantization for tamper detection

    Publication Year: 2002 , Page(s): IV-3305 - IV-3308
    Cited by:  Papers (4)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (707 KB) |  | HTML iconHTML  

    A fragile speech watermarking scheme of low complexity is proposed in this research as an effective way to detect malicious content alterations while tolerating content preserving operations. Since no auxiliary data are required, the authentication process is transparent to agents that perform content preserving operations such as transcoding during the transmission process. The proposed scheme is based on the modified odd/even modulation scheme with exponential scale quantization and a localized frequency masking model while assuring no mismatch between quantization steps used in watermark embedding and detection. The noise introduced by watermarking is shown to be smaller than that of speech coders. It is shown by experimental results that the proposed system is able to distinguish malicious alterations from resampling, white noise pollution, G.711 speech coding and G.721 speech coding with very low error probabilities. View full abstract»

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  • Collusion-resistant fingerprinting for multimedia

    Publication Year: 2002 , Page(s): IV-3309 - IV-3312
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (789 KB) |  | HTML iconHTML  

    Digital fingerprinting is an effective method to identify users who might try to redistribute multimedia content, such as images and video. These fingerprints are typically embedded into the content using watermarking techniques that are designed to be robust to a variety of attacks. A cheap and effective attack against such digital fingerprints is collusion, where several differently marked copies of the same content are averaged or combined to disrupt the underlying fingerprint. In this paper, we study the problem of designing fingerprints that can withstand collusion, yet trace colluders. Since, in antipodal CDMA-type watermarking, the correlation contributions only decrease where watermarks differ, by constructing binary code vectors where any subset of k or fewer of these vectors have unique overlap, we may identify groups of k or less colluders. Our construction of such anti-collusion codes (ACC) uses the theory of combinatorial designs, and for n users requires O(√n) bits. Further, we explore a block matrix structure for the ACC that reduces the computational complexity for identifying colluders and improves the detection capability when colluders belong to the same subgroup. View full abstract»

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  • Why is image quality assessment so difficult?

    Publication Year: 2002 , Page(s): IV-3313 - IV-3316
    Cited by:  Papers (63)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (816 KB) |  | HTML iconHTML  

    Image quality assessment plays an important role in various image processing applications. A great deal of effort has been made in recent years to develop objective image quality metrics that correlate with perceived quality measurement. Unfortunately, only limited success has been achieved. In this paper, we provide some insights on why image quality assessment is so difficult by pointing out the weaknesses of the error sensitivity based framework, which has been used by most image quality assessment approaches in the literature. Furthermore, we propose a new philosophy in designing image quality metrics: The main function of the human eyes is to extract structural information from the viewing field, and the human visual system is highly adapted for this purpose. Therefore, a measurement of structural distortion should be a good approximation of perceived image distortion. Based on the new philosophy, we implemented a simple but effective image quality indexing algorithm, which is very promising as shown by our current results. View full abstract»

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  • An overview of similarity measures for images

    Publication Year: 2002 , Page(s): IV-3317 - IV-3320
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (643 KB) |  | HTML iconHTML  

    Fuzzy techniques can be applied in several domains of image processing. In this paper we will show how notions of fuzzy set theory are used in establishing measures for image quality evaluation. Objective quality measures or measures of comparison are of great importance in the field of image processing. Such measures are necessary for the evaluation and the comparison of different algorithms that are designed to solve a similar problem, and consequently they serve as a basis on which algorithm is preferred to the other. In this paper, we will show how similarity measures originally introduced to compare two fuzzy sets can be applied successfully in the domain of image processing. View full abstract»

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  • Towards a criterion for evaluating the quality of 3D reconstructions

    Publication Year: 2002 , Page(s): IV-3321 - IV-3324
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (725 KB) |  | HTML iconHTML  

    Even though numerous algorithms exist for estimating the structure of a scene from its video, the solutions obtained are often of unacceptable quality. To overcome some of the deficiencies, many application systems rely on processing more information than necessary with the hope that the redundancy will help improve the quality. This raises the question about how the accuracy of the solution is related to the amount of information processed by the algorithm. Can we define the accuracy of the solution precisely enough that we automatically recognize situations where the quality of the data is so bad that even a large number of additional observations will not yield the desired solution? This paper proposes an information theoretic criterion for evaluating the quality of a 3D reconstruction in terms of the statistics of the observed parameters (i.e. the image correspondences). The accuracy of the reconstruction is judged by considering the change in mutual information (or equivalently the conditional differential entropy) between a scene and its reconstructions and its effectiveness is shown through simulations. View full abstract»

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