Chair of
Multimedia Communications and Signal Processing
Prof. Dr.-Ing. André Kaup

Mobile In-Car TV-Reception

Field of activity: Video Signal Processing and Transmission
Research topic: Video Coding and Transmission
Staff: Dr.-Ing. Tobias Tröger

Currently, modern cars are usually equipped with infotainment systems which enable digital TV reception. However, reception conditions are adverse in cars leading to distortions of the broadcasted television signal. At the receiver, errors can be detected and correct to a certain extent applying forward error correction schemes. Because of remaining errors, artifacts may occur in the decoding step signficantly affecting the visual quality of the decoded video signal.

Figure 1: Automotive Multi-Standard Reception
Figure 1: Automotive multi-standard reception


Up to now, hybrid TV receivers have been integrated into cars switching between analog and digital TV reception in case of errors. Future multi-broadcast receivers (MBR) will not support analog but a plurality of digital terrestrial broadcasting standards such as ATSC, DVB-T, DVB-H, ISDB-T or T-DMB. Assuming simultaneous reception of these broadcasting techniques, coextensive television signals are available at such a multi-broadcast receiver which can be combined in case of errors (inter-sequence error concealment). Figure 1 exemplarily shows the automotive multi-standard tv reception of both DVB-T and T-DMB signals. A possible layout of a future multi-broadcast receiver is depicted in Figure 2.

Figure 2: Possible layout of a future multi-broadcast receiver
Figure 2: Possible layout of a future multi-broadcast receiver


In this research project, the basis for a future multi-broadcast receiver shall be developed. In particular, it shall be examined how far the quality of an erroneously received TV signal can be increased by image combination. The combination of several TV signals is obvious as several representations of a particular TV program is available at a multi-broadcast receiver. This technique represents a novel approach for error concealment of erroneous image and video data. For example, erroneous pixels of a distorted DVB-T signal can be concealed by inserting corresponding error-free pixels of a reference signal (e.g. a DVB-H signal or a T-DMB signal). However, the quality of concealed pixels strongly depends on the temporal alignment and spatial registration of both the distorted signal and the reference signal.

This research project is supported by Audi AG in Ingolstadt and Ingolstadt Institute der Friedrich-Alexander-Universität Erlangen-Nürnberg (INI.FAU).

Current results

Figure 3 shows the visual reconstruction quality of concealed pixels of an erroneous DVB-T signal using a reference signal which is highly compressed. Here, an error-free DVB-H signal is used as a reference which - as already mentioned above - has to be temporally aligned and spatially registered previous to the actual combination step. Because of the high compression of the reference signal, block artifacts arise in the concealed DVB-T signal which clearly come to the fore in the zoomed image on the right.

Figure 3: Inter-sequence error concealment
Figure 3: Inter-sequence error concealment of a distorted DVB-T signal (high compression of the reference signal)


Figure 4 shows he visual reconstruction quality of concealed samples of an erroneous DVB-T signal using a reference signal which is slightly compressed. Again, an error-free is utilized as a reference signal. The block artifacts depicted in Figure 3 have vanished here due to the slight compression of the reference. This, the subjective image quality of concealed image parts increases significantly.

Figure 4: Inter-sequence error concealment
Figure 4: Inter-sequence error concealment of a distorted DVB-T signal (low compression of the reference signal)

The objective reconstruction quality of an erroneous DVB-T signal is depicted in Figure 5 which has been reconstructed by inter-sequence error concealment. The peak-signal-to-noise ratio (PSNR) is plotted against the bitrate of the coded reference signal (here: DVB-H signa=). For simulations, 4 models are considered to generate the reference signal (CIF-resized, CIF-resized&cropped, QVGA-resized, QVGA-resized&cropped). Figure 5 additionally shows the reconstruction quality of conventional temporal error concealment techniques for comparison (here: Boundary Matching Algorithm (BMA) and Decoder Motion Vector Estimation (DMVE)).

Figure 5: rate-distortion curve
Figure 5: Objective reconstruction quality of a DVB-T signal reconstructed by inter-sequence error concealment

Publications

2011-55
CRIS
T. Tröger, A. Kaup
   [link]   [doi]   [bib]

Inter-Sequence Error Concealment Techniques for Multi-Broadcast TV Reception
IEEE Transactions on Broadcasting Vol. 57, Num. 4, Pages: 777-793, Dec. 2011
2011-30
CRIS
T. Tröger, A. Kaup
   [link]   [bib]

Temporal Adaptation Strategies for Spatio-Temporal Image Alignment in Inter-Sequence Error Concealment of Digital TV
IEEE Int. Conf. on Image Processing (ICIP), Brussels, Belgium, Sep. 2011
2011-11
CRIS
T. Tröger, M. Hirschbeck, A. Kaup
   [link]   [bib]

Performance Evaluation of Feature-Based Image Alignment Techniques for Inter-Sequence Error Concealment
14th ITG Conference on Electronic Media Technology, Dortmund, Germany, Mar. 2011
2011-8
CRIS
T. Tröger, A. Kaup
   [link]   [doi]   [bib]

Difference Image Extrapolation for Spectral Completion in Inter-Sequence Error Concealment
IEEE Int. Conf. on Acoustics, Speech and Signal Processing (ICASSP), Prague, Czech Republic, May 2011
2010-42
CRIS
T. Tröger, J. Seiler, A. Kaup
   [link]   [doi]   [bib]

Spatially Refined Inter-Sequence Error Concealment for a Multi-Broadcast Receiver Using Frequency Selective Approximation
18th Annual ACM International Conference on Multimedia, Pages: 1203-1206, Florence, Italy, Oct. 2010
2010-31
CRIS
T. Tröger, A. Kaup
   [link]   [doi]   [bib]

Fast and Robust Spatio-Temporal Image Alignment for Inter-Sequence Error Concealment
IEEE International Conference on Image Processing (ICIP 2010), Pages: 445-448, Hong Kong, Sep. 2010
2010-17 T. Tröger, H. Heiber, A. Schmitt, A. Kaup
   [link]   [bib]

Verfahren zum Gewinnen von Bildern bei Mehrfachempfang
DE 10 2008 039051 A1, Feb. 2010
2010-16 T. Tröger, H. Heiber, A. Schmitt, A. Kaup
   [link]   [bib]

Method for obtaining images during multiple receptions
WO/2010/020336, Feb. 2010
2010-4
CRIS
T. Tröger, H. Heiber, A. Schmitt, A. Kaup
   [link]   [doi]   [bib]

Improved Mode Selection in Hybrid Error Concealment for Multi-Broadcast-Reception
IEEE International Symposium on Circuits and Systems (ISCAS), Pages: 3645-3648, Paris, France, May 2010
2009-37
CRIS
T. Tröger, H. Heiber, A. Schmitt, A. Kaup
   [link]   [bib]

Joint Temporal and Inter-Sequence Error Concealment for Multi-Broadcast-Reception
10th Workshop Digital Broadcasting, Pages: 95-102, Ilmenau, Germany, Sep. 2009
2009-28
CRIS
T. Tröger, H. Heiber, A. Schmitt, A. Kaup
   [link]   [doi]   [bib]

Low-Complexity Inter-Sequence Error Concealment based on Scale-Invariant Feature Transform
IEEE International Workshop on Multimedia Signal Processing (MMSP), Rio de Janeiro, Brazil, Oct. 2009
2009-18
CRIS
T. Tröger, H. Heiber, A. Schmitt, A. Kaup
   [link]   [bib]

Inter-Sequence Error Concealment for Diversity Reception of TV Sequences
European Signal Processing Conference, Pages: 569-573, Aug. 2009
2009-6
CRIS
T. Tröger, H. Heiber, A. Schmitt, A. Kaup
   [bib]

Fehlerverschleierung digitaler Fernsehbildsignale bei mobilem Mehrfachempfang
ITG Fachtagung für Elektronische Medien, Pages: 158-163, Dortmund, Deutschland, Mar. 2009
2008-29
CRIS
T. Tröger, H. Heiber, A. Schmitt, A. Kaup
   [link]   [bib]

Image-Based Synchronization in Mobile TV for a Multi-Broadcast-Receiver
9th Workshop Digital Broadcasting, Pages: 139-144, Tennenlohe, Germany, Sep. 2008
2008-28
CRIS
T. Tröger, J. Garbas, H. Heiber, A. Schmitt, A. Kaup
   [link]   [bib]

Inter-Sequence Error Concealment of High-Resolution Video Sequences in a Multi-Broadcast-Reception Scenario
16th European Signal Processing Conference (EUSIPCO), Lausanne, Switzerland, Aug. 2008