Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342426
J. Z. Chang, J. Allebach
Balasubramanian et al. (1993) proposed an efficient vector quantization method called sequential scalar quantization (SSQ). In this method, the scalar components of the vector are individually quantized in a sequence, with the quantization of each component utilizing conditional information from the quantization of previous components. It has been shown that SSQ performs far better than conventional independent scalar quantization, while offering significant computational advantage over conventional VQ techniques. However, the design technique was a greedy method. The present authors use asymptotic quantization theory to derive a globally optimal design procedure for SSQ. With this method, the quantization of a scalar depends not only on its marginal density conditioned on the previously quantized scalars, but also on the distribution of the unquantized scalars. They also present simulation results to illustrate the relative performance of these two design methods with a moderate number of quantization levels.<>
{"title":"Optimal sequential scalar quantization of vectors","authors":"J. Z. Chang, J. Allebach","doi":"10.1109/ACSSC.1993.342426","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342426","url":null,"abstract":"Balasubramanian et al. (1993) proposed an efficient vector quantization method called sequential scalar quantization (SSQ). In this method, the scalar components of the vector are individually quantized in a sequence, with the quantization of each component utilizing conditional information from the quantization of previous components. It has been shown that SSQ performs far better than conventional independent scalar quantization, while offering significant computational advantage over conventional VQ techniques. However, the design technique was a greedy method. The present authors use asymptotic quantization theory to derive a globally optimal design procedure for SSQ. With this method, the quantization of a scalar depends not only on its marginal density conditioned on the previously quantized scalars, but also on the distribution of the unquantized scalars. They also present simulation results to illustrate the relative performance of these two design methods with a moderate number of quantization levels.<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"139 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131404391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342472
M. Khansari, Tsuhan Chen
The commutativity of multidimensional downsamplers and upsamplers have been discussed very intensively for the past few years. This is due to its important applications in sampling structure conversion, e.g., the conversion between conventional television signals and high definition television (HDTV) signals. Among many other results, one useful test for such commutativity was found to be that the two matrices which define the multidimensional downsampling and upsampling should be commutative and coprime. However, the problem of finding multidimensional downsamplers and upsamplers that satisfy these conditions has remained open. In this paper, we develop a systematic procedure to solve this open problem.<>
{"title":"On commutativity of multidimensional downsamplers and upsamplers","authors":"M. Khansari, Tsuhan Chen","doi":"10.1109/ACSSC.1993.342472","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342472","url":null,"abstract":"The commutativity of multidimensional downsamplers and upsamplers have been discussed very intensively for the past few years. This is due to its important applications in sampling structure conversion, e.g., the conversion between conventional television signals and high definition television (HDTV) signals. Among many other results, one useful test for such commutativity was found to be that the two matrices which define the multidimensional downsampling and upsampling should be commutative and coprime. However, the problem of finding multidimensional downsamplers and upsamplers that satisfy these conditions has remained open. In this paper, we develop a systematic procedure to solve this open problem.<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134478188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342446
Jianping Wang, I. Greenshields
The explosive growth in the availability of three-dimensional imaging technologies (such as magnetic resonance imagery (MRI) and computer-assisted tomography (CAT)) has transformed the issue of three-dimensional shape description from a purely abstract exercise in differential geometry to one with practical implications. The paper explores the problem of constructing a rotationally-invariant "sampling lattice" for objects which are diffeomorphic to the unit sphere whose shape functions are L/sup 2/ and bounded in norm with respect to their Laplacian by using local R/sup 2/ approximations to the S/sup 2/ shape functions. The approach used follows a line of argument presented by Daubechies (1990).<>
{"title":"Local approximation of curvature-bounded shape functions on S/sup 2/-diffeomorphic manifolds","authors":"Jianping Wang, I. Greenshields","doi":"10.1109/ACSSC.1993.342446","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342446","url":null,"abstract":"The explosive growth in the availability of three-dimensional imaging technologies (such as magnetic resonance imagery (MRI) and computer-assisted tomography (CAT)) has transformed the issue of three-dimensional shape description from a purely abstract exercise in differential geometry to one with practical implications. The paper explores the problem of constructing a rotationally-invariant \"sampling lattice\" for objects which are diffeomorphic to the unit sphere whose shape functions are L/sup 2/ and bounded in norm with respect to their Laplacian by using local R/sup 2/ approximations to the S/sup 2/ shape functions. The approach used follows a line of argument presented by Daubechies (1990).<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124335362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342548
Nathan Yee, Jean-Paul Linnartz
The paper analyzes a novel digital modulation technique called multi-carrier code division multiple access (MC-CDMA) in which data symbols are transmitted at multiple subcarriers where each subcarrier is modulated by a 1 or -1 based on a spreading code. Analytical results are presented on the performance of this modulation scheme in the downlink of an indoor wireless Rician fading channel. In addition, the performance of a controlled equalization technique that attempts to restore the orthogonality between users is evaluated.<>
{"title":"BER of multi-carrier CDMA in an indoor Rician fading channel","authors":"Nathan Yee, Jean-Paul Linnartz","doi":"10.1109/ACSSC.1993.342548","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342548","url":null,"abstract":"The paper analyzes a novel digital modulation technique called multi-carrier code division multiple access (MC-CDMA) in which data symbols are transmitted at multiple subcarriers where each subcarrier is modulated by a 1 or -1 based on a spreading code. Analytical results are presented on the performance of this modulation scheme in the downlink of an indoor wireless Rician fading channel. In addition, the performance of a controlled equalization technique that attempts to restore the orthogonality between users is evaluated.<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124039717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342394
R. Nitzberg
A composite CFAR (constant false alarm rate) technique that uses CACFAR for a homogeneous environment and adaptively switches to an alternate CFAR technique for nonhomogeneity is synthesized. The influence of switching level upon CFAR loss is established. The loss is evaluated and graphed for the OSCFAR alternate technique.<>
{"title":"Composite CFAR techniques [radar]","authors":"R. Nitzberg","doi":"10.1109/ACSSC.1993.342394","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342394","url":null,"abstract":"A composite CFAR (constant false alarm rate) technique that uses CACFAR for a homogeneous environment and adaptively switches to an alternate CFAR technique for nonhomogeneity is synthesized. The influence of switching level upon CFAR loss is established. The loss is evaluated and graphed for the OSCFAR alternate technique.<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121185662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342429
R.A. Vander Kam, P. Chou, R. Gray
Presents a quantitative comparison of the performance and complexity of several block-based algorithms for digital halftoning. The performance measurements are based on a model of the human visual system. The suitability of these halftoning algorithms for use in combined halftoning and compression systems is also evaluated.<>
{"title":"Performance evaluation of greedy search algorithms for image halftoning and compression","authors":"R.A. Vander Kam, P. Chou, R. Gray","doi":"10.1109/ACSSC.1993.342429","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342429","url":null,"abstract":"Presents a quantitative comparison of the performance and complexity of several block-based algorithms for digital halftoning. The performance measurements are based on a model of the human visual system. The suitability of these halftoning algorithms for use in combined halftoning and compression systems is also evaluated.<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121385689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342632
M. Soderstrand, D. Chu, W. Chan, M. Lazkani, H. Loomis
In decoding spread-spectrum BPSK signals in the presence of narrow-band interference, a perfect reconstruction multi-rate bandpass filter bank can be used with a very simple adaptive algorithm to eliminate narrow-band interference broadband signals. Inherent in this structure is the need to do quadrature processing to eliminate images that occur due to the up-sampling required to obtain the narrow-band bandpass filters. We propose to use parallel processors (microprocessors, ASICs, or DSP chips) to implement complex FIR filters needed to eliminate the upsampled images. The processors implement a very simple complex FIR filter in one modulus of a generalized quadratic residue number system (GQRNS). By keeping the moduli small and the filter order low, it is possible to use standard binary within the processor to implement a GQRNS number system. This allows us to obtain the advantages of parallel processing and simplified complex number arithmetic inherent in GQRNS arithmetic while maintaining standard binary arithmetic in the processors.<>
{"title":"Multi-rate bandpass filter bank implemented in QRNS complex arithmetic using parallel multiple DSP chips or ASICs","authors":"M. Soderstrand, D. Chu, W. Chan, M. Lazkani, H. Loomis","doi":"10.1109/ACSSC.1993.342632","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342632","url":null,"abstract":"In decoding spread-spectrum BPSK signals in the presence of narrow-band interference, a perfect reconstruction multi-rate bandpass filter bank can be used with a very simple adaptive algorithm to eliminate narrow-band interference broadband signals. Inherent in this structure is the need to do quadrature processing to eliminate images that occur due to the up-sampling required to obtain the narrow-band bandpass filters. We propose to use parallel processors (microprocessors, ASICs, or DSP chips) to implement complex FIR filters needed to eliminate the upsampled images. The processors implement a very simple complex FIR filter in one modulus of a generalized quadratic residue number system (GQRNS). By keeping the moduli small and the filter order low, it is possible to use standard binary within the processor to implement a GQRNS number system. This allows us to obtain the advantages of parallel processing and simplified complex number arithmetic inherent in GQRNS arithmetic while maintaining standard binary arithmetic in the processors.<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"86 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128835081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342503
R. Iltis, K.L. Anderson
The problem of multitarget tracking using bearings-only measurements is addressed, when the number of targets is unknown a-priori. The minimum description length (MDL) criterion of Rissanen (1983) is first chosen as a natural way to determine the number of targets when a prior distribution is unavailable. However, it is shown that the MDL criterion lends to overestimate the number of targets, and hence a modified criterion is proposed. The resulting algorithm corresponds to the computation of joint maximum likelihood estimates of target states and associations, with an additional penalty term to prevent overparameterization. The problem of data association is solved using a set of parallel simulated annealing algorithms over the sensors and scans. As the associations are formed by annealing, a conventional nonlinear programming algorithm simultaneously estimates the target states (position and velocity). The consistency of the new estimation criterion is proven analytically in the case of a clean environment. Simulation results are presented which compare the tracking performance of the MDL and modified estimation algorithms, for cases with and without clutter.<>
{"title":"Multisensor bearings-only tracking using the MDL criterion","authors":"R. Iltis, K.L. Anderson","doi":"10.1109/ACSSC.1993.342503","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342503","url":null,"abstract":"The problem of multitarget tracking using bearings-only measurements is addressed, when the number of targets is unknown a-priori. The minimum description length (MDL) criterion of Rissanen (1983) is first chosen as a natural way to determine the number of targets when a prior distribution is unavailable. However, it is shown that the MDL criterion lends to overestimate the number of targets, and hence a modified criterion is proposed. The resulting algorithm corresponds to the computation of joint maximum likelihood estimates of target states and associations, with an additional penalty term to prevent overparameterization. The problem of data association is solved using a set of parallel simulated annealing algorithms over the sensors and scans. As the associations are formed by annealing, a conventional nonlinear programming algorithm simultaneously estimates the target states (position and velocity). The consistency of the new estimation criterion is proven analytically in the case of a clean environment. Simulation results are presented which compare the tracking performance of the MDL and modified estimation algorithms, for cases with and without clutter.<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129042406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342575
Jitendra Malik, R. Rosenholtz
We model the texture distortion at a point in any particular direction on the image plane as an affine transformation and derive the relationship between the parameters of the affine transformation and the surface shape and orientation. We use a technique for estimating affine transforms between nearby image patches which is based on solving a system of linear constraints derived from a differential analysis. It is not necessary to explicitly identify texels or make restrictive assumptions about the nature of the image texture like isotropy. We have developed two different algorithms for recovering surface orientation and shape based on the estimated affine transforms in a number of different directions. The first is a sample linear algorithm based on singular value decomposition. The second is based on nonlinear minimization of a least squares error criterion. Experimental results are presented on images of planar and curved surfaces under perspective projection.<>
{"title":"A differential method for computing local shape-from-texture for planar and curved surfaces","authors":"Jitendra Malik, R. Rosenholtz","doi":"10.1109/ACSSC.1993.342575","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342575","url":null,"abstract":"We model the texture distortion at a point in any particular direction on the image plane as an affine transformation and derive the relationship between the parameters of the affine transformation and the surface shape and orientation. We use a technique for estimating affine transforms between nearby image patches which is based on solving a system of linear constraints derived from a differential analysis. It is not necessary to explicitly identify texels or make restrictive assumptions about the nature of the image texture like isotropy. We have developed two different algorithms for recovering surface orientation and shape based on the estimated affine transforms in a number of different directions. The first is a sample linear algorithm based on singular value decomposition. The second is based on nonlinear minimization of a least squares error criterion. Experimental results are presented on images of planar and curved surfaces under perspective projection.<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116104904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1993-11-01DOI: 10.1109/ACSSC.1993.342637
M. J. Flanagan, G. Zimmerman
A higher-order phase dithering technique that reduces the complexity of digital sinusoid generation is presented and analyzed. M/sup th/ order phase dithering denotes the addition of M independent, uniform variates to the sinusoid phase prior to word-length reduction. Spurious magnitudes due to quantization effects are accelerated from the usual -6 dBc per phase bit to -6(M+1) dBc per phase bit, while the noise power increases linearly in M. For a given spurious specification, higher-order phase dithering permits the use of fewer phase bits than the non-dithered system, resulting in an exponential reduction in look-up table size, dramatically decreasing system complexity.<>
{"title":"Spur-reduced digital sinusoid generation using higher-order phase dithering","authors":"M. J. Flanagan, G. Zimmerman","doi":"10.1109/ACSSC.1993.342637","DOIUrl":"https://doi.org/10.1109/ACSSC.1993.342637","url":null,"abstract":"A higher-order phase dithering technique that reduces the complexity of digital sinusoid generation is presented and analyzed. M/sup th/ order phase dithering denotes the addition of M independent, uniform variates to the sinusoid phase prior to word-length reduction. Spurious magnitudes due to quantization effects are accelerated from the usual -6 dBc per phase bit to -6(M+1) dBc per phase bit, while the noise power increases linearly in M. For a given spurious specification, higher-order phase dithering permits the use of fewer phase bits than the non-dithered system, resulting in an exponential reduction in look-up table size, dramatically decreasing system complexity.<<ETX>>","PeriodicalId":266447,"journal":{"name":"Proceedings of 27th Asilomar Conference on Signals, Systems and Computers","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116910511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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