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Andersson, Kenneth
Publications (8 of 8) Show all publications
Andersson, K., Westin, C.-F. & Knutsson, H. (2007). Prediction from off-grid samples using continuous normalized convolution. Signal Processing, 87(3), 353-365
Open this publication in new window or tab >>Prediction from off-grid samples using continuous normalized convolution
2007 (English)In: Signal Processing, ISSN 0165-1684, E-ISSN 1872-7557, Vol. 87, no 3, p. 353-365Article in journal (Refereed) Published
Abstract [en]

This paper presents a novel method for performing fast estimation of data samples on a desired output grid from samples on an irregularly sampled grid. The output signal is estimated using integration of signals over a neighbourhood employing a local model of the signal using discrete filters. The strength of the method is demonstrated in motion compensation examples by comparing to traditional techniques.

National Category
Signal Processing
Identifiers
urn:nbn:se:liu:diva-22103 (URN)10.1016/j.sigpro.2006.04.011 (DOI)000242697400001 ()1197 (Local ID)1197 (Archive number)1197 (OAI)
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2017-12-13
Andersson, K., Andersson, M., Johansson, P., Forchheimer, R. & Knutsson, H. (2003). Motion compensation using backward prediction and prediction refinement. Signal Processing: Image Communication, 18(5), 381-400
Open this publication in new window or tab >>Motion compensation using backward prediction and prediction refinement
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2003 (English)In: Signal Processing: Image Communication, ISSN 0923-5965, Vol. 18, no 5, p. 381-400Article in journal (Refereed) Published
Abstract [en]

This paper presents new methods for use of dense motion fields for motion compensation of interlaced video. The motion estimation is based on previously decoded field-images. The motion is then temporally predicted and used for motion compensated prediction of the field-image to be coded. The motion estimation algorithm is phase-based and uses two or three field-images to achieve motion estimates with sub-pixel accuracy. To handle non-constant motion and the specific characteristics of the field-image to be coded, the initially predicted image is refined using forward motion compensation, based on block-matching. Tests show that this approach achieves higher PSNR than forward block-based motion estimation, when coding the residual with the same coder. The subjective performance is also better.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-24495 (URN)10.1016/S0923-5965(03)00012-2 (DOI)6619 (Local ID)6619 (Archive number)6619 (OAI)
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2013-08-28
Andersson, K. (2003). Motion estimation for perceptual image sequence coding. (Doctoral dissertation). Linköping: Linköpings Universitet
Open this publication in new window or tab >>Motion estimation for perceptual image sequence coding
2003 (English)Doctoral thesis, monograph (Other academic)
Abstract [en]

Since the advent of television obtaining high perceived quality using a limited bandwidth has been an important issue. This thesis proposes new methods for exploitation of temporal and perceptual redundancy in image sequences to achieve lower coding rate and/or higher visual quality. The methods presented are inspired and based on human visual system models. Particularly relevant in the present context are the indications that the visual cortex contains cells that are selective in orientation and frequency but invariant to the phase of the stimuli. For this reason a spatial quadrature filter bank, representing images in a similar fashion, is generated. For computational eciency, a filter net technique is employed using combinations of simple sequential 1D filter kernels. The lter bank is designed for interlaced video which is still the most common format for video sequences.

For coding of image sequences temporal redundancy is reduced using motion compensated prediction. In motion compensated prediction the prediction of the next image is given by the present image and a predicted dense local motion field. Motion compensation is performed with a new and computationally ecient method. The method estimates data samples on a desired output grid from input data represented by samples on an irregularly grid. The initially predicted image is refined using forward motion compensation with a sparse motion field. In this case only the sparse motion field needs to be transmitted to the decoder. As a result a prediction without block artifacts, common in standard forward motion compensation schemes, is generated. Experiments show that this method performs better than traditional block-matching approaches.

The motion is estimated using a new approach based on phase differences computed from products of quadrature filter responses. The approach includes learning parameters for motion estimation and introduces multiple hierarchical motion estimation to achieve estimates with high spatial resolution.

The quadrature lter bank approach used for motion estimation also provides a basis for image quality estimation in accordance with human perception. This allows the video quality estimator to be an integral part of the video coder and opens up the possibility of local space-time optimization of video coding parameters.

Place, publisher, year, edition, pages
Linköping: Linköpings Universitet, 2003. p. 140
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 794
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-24498 (URN)6622 (Local ID)91-7373-482-9 (ISBN)6622 (Archive number)6622 (OAI)
Public defence
2003-01-24, Elsa Brändströmsalen, Universitetssjukhuset, Linköping, 10:15 (Swedish)
Opponent
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2012-12-18
Andersson, K., Johansson, P., Forchheimer, R. & Knutsson, H. (2002). Backward-forward motion compensated prediction. In: Proceedings of ACIVS 2002 (Advanced Concepts for Intelligent Vision Systems), Ghent, Belgium, September 9-11, 2002: . Paper presented at ACIVS 2002, Ghent, Belgium, September 9-11, 2002 (pp. 260-267).
Open this publication in new window or tab >>Backward-forward motion compensated prediction
2002 (English)In: Proceedings of ACIVS 2002 (Advanced Concepts for Intelligent Vision Systems), Ghent, Belgium, September 9-11, 2002, 2002, p. 260-267Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents new methods for use of dense motion fields for motion compensation of interlaced video. The motion is estimated using previously decoded field-images. An initial motion compensated prediction is produced using the assumption that the motion is predictable in time. The motion estimation algorithm is phase-based and uses two or three field-images to achieve motion estimates with sub-pixel accuracy. To handle non-constant motion and the specific characteristics of the field-image to be coded, the initially predicted image is refined using forward motion compensation, based on block-matching. Tests show that this approach achieves higher PSNR than forward block-based motion estimation, when coding the residual with the same coder. The subjective performance is also better.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-24519 (URN)6651 (Local ID)6651 (Archive number)6651 (OAI)
Conference
ACIVS 2002, Ghent, Belgium, September 9-11, 2002
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2013-08-28
Andersson, K. & Knutsson, H. (2002). Continuous normalized convolution. In: Multimedia and Expo, 2002. ICME '02. Proceedings. 2002 IEEE International Conference on  (Volume:1): . Paper presented at IEEE International Conference on Multimedia and Expo, Lausanne, Switzerland, 2002 (pp. 725-728). IEEE
Open this publication in new window or tab >>Continuous normalized convolution
2002 (English)In: Multimedia and Expo, 2002. ICME '02. Proceedings. 2002 IEEE International Conference on  (Volume:1), IEEE , 2002, p. 725-728Conference paper, Published paper (Refereed)
Abstract [en]

The problem of signal estimation for sparsely and irregularly sampled signals is dealt with using continuous normalized convolution. Image values on real-valued positions are estimated using integration of signals and certainties over a neighbourhood employing a local model of both the signal and the used discrete filters. The result of the approach is that an output sample close to signals with high certainty is interpolated using a small neighbourhood. An output sample close to signals with low certainty is spatially predicted from signals in a large neighbourhood.

Place, publisher, year, edition, pages
IEEE, 2002
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-24521 (URN)10.1109/ICME.2002.1035884 (DOI)6653 (Local ID)0-7803-7304-9 (ISBN)6653 (Archive number)6653 (OAI)
Conference
IEEE International Conference on Multimedia and Expo, Lausanne, Switzerland, 2002
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2013-08-28Bibliographically approved
Andersson, K. & Knutsson, H. (2002). Multiple hierarchical motion estimation. In: M.H. Hamza (Ed.), Signal Processing, Pattern Recognition, and Applications - 2002: . Paper presented at Signal Processing, Pattern Recognition, and applications (SPPRA 2002), Crete, Greece, June 25 – 28, 2002 (pp. 80). ACTA Press
Open this publication in new window or tab >>Multiple hierarchical motion estimation
2002 (English)In: Signal Processing, Pattern Recognition, and Applications - 2002 / [ed] M.H. Hamza, ACTA Press, 2002, p. 80-Conference paper, Published paper (Refereed)
Abstract [en]

This paper introduce multiple hierarchical motion estimation to achieve motion estimates with high spatial resolution. The approach is based on phase-based motion estimation. Results show that the algorithm deal with the smooth motion field of hierarchical motion estimation while keeping the advantages of such an approach.

Place, publisher, year, edition, pages
ACTA Press, 2002
Keywords
motion estimation, phase, learning, motion compensation
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-24520 (URN)6652 (Local ID)6652 (Archive number)6652 (OAI)
Conference
Signal Processing, Pattern Recognition, and applications (SPPRA 2002), Crete, Greece, June 25 – 28, 2002
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2013-08-28Bibliographically approved
Andersson, K. (2002). Quality and motion estimation for image sequence coding. (Licentiate dissertation). Linköping: Linköpings universitet
Open this publication in new window or tab >>Quality and motion estimation for image sequence coding
2002 (English)Licentiate thesis, monograph (Other academic)
Abstract [en]

Since the advent of television obtaining high perceived quality using a limited bandwidth has been an important issue. This thesis proposes methods inspired and based on the human visual system for exploitation of temporal and perceptual redundancy in image sequences to achieve lower coding rate and/ or higher visual quality. Particularly relevant in the present context are the indications that the visual cortex contains cells that are selective in orientation and frequency but invariant to the phase of the stimuli. For this reason and for computational efficiency, a spatial quadrature filter bank is generated initially using combinations of simple sequential 1D filter kernels.

The temporal redtmdancy is reduced using motion compensated prediction. Motion compensation predicts the frame to be transmitted by moving the previous decoded frame according to its motion, so called backward coding. This means that no information about motion needs to be transmitted to the decoder. The irregular sampling of the prediction, due to motion estimates with sub-pixel accuracy, is dealt with using a new method, continuous normalized convolution. Image values on an interlaced sampling grid are estimated from the irregularly sampled predictions using integration of signals and certainties over a neighbourhood employing a local model of both the signal and the integration filter. The motion is estimated from products of quadrature filter bank responses, generating phasebased channels tuned for velocity. This new approach includes learning parameters for motion estimation and introduces multiple hierarchical motion estimation toachieve estimates with high spatial resolution.

Using the quadrature filter bank a new quality estimator, based on a human visual system model, is generated. The quality estimator can be used to reduce the perceptual redundancy of non-visible errors and is intended to improve coding performance in such regions.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2002. p. 78
Series
Linköping Studies in Science and Technology. Thesis, ISSN 0280-7971 ; 928
Series
LiU-TEK-LIC ; 1
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-29554 (URN)14925 (Local ID)91-7373-264-8 (ISBN)14925 (Archive number)14925 (OAI)
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2013-11-13
Andersson, K., Andersson, M. & Knutsson, H. (2001). A perception based velocity estimator and its use for motion compensated prediction. In: SCIA 2001 Scandinavian Conference on Image Analysis,2001: . Paper presented at SCIA 2001 Scandinavian Conference on Image Analysis, 11-14 June 2001, Bergen, Norway (pp. 493-499).
Open this publication in new window or tab >>A perception based velocity estimator and its use for motion compensated prediction
2001 (English)In: SCIA 2001 Scandinavian Conference on Image Analysis,2001, 2001, p. 493-499Conference paper, Published paper (Refereed)
Abstract [en]

The use of temporal redundancy is of vital importance for a successful video coding algorithm. An effective approach is the hybrid video coder where motion estimation is used for prediction of the next image frame and code the prediction error, and the motion field. The standard method for motion estimation is block matching as in MPEG-2, typically resulting in block artifacts. In this paper a perception based velocity estimator and its use for pixel based motion compensated prediction of interlaced video is presented.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:liu:diva-29010 (URN)14244 (Local ID)14244 (Archive number)14244 (OAI)
Conference
SCIA 2001 Scandinavian Conference on Image Analysis, 11-14 June 2001, Bergen, Norway
Available from: 2009-10-09 Created: 2009-10-09 Last updated: 2015-04-16
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