Video/Image Processing


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Video/Image Processing

  1. 1. <ul><li>Video-Based </li></ul><ul><li>Sensor Networks </li></ul><ul><li>H. GHARAVI </li></ul><ul><li>K. Ban </li></ul><ul><li>NIST </li></ul>
  2. 2. Video- Based Sensor Networks <ul><li>Video streaming </li></ul><ul><ul><li>RTP </li></ul></ul><ul><li>Networking </li></ul><ul><ul><li>Multi-hop/Ad-hoc </li></ul></ul><ul><li>Transport Systems </li></ul><ul><ul><li>IEEE 802.11b </li></ul></ul><ul><ul><ul><li>DSSS </li></ul></ul></ul><ul><ul><ul><li>FHSS </li></ul></ul></ul><ul><li>Implementations </li></ul><ul><ul><li>SPW software implementation to evaluate the network deign </li></ul></ul><ul><ul><li>iPAQ based experimental setup for real-time demo </li></ul></ul>
  3. 3. Multi-hop Sensor Networks <ul><li>Requirements; </li></ul><ul><ul><li>Energy efficient </li></ul></ul><ul><ul><li>Scalable </li></ul></ul><ul><li>For an efficient and robust system IEEE 802.11 FHSS is considered. </li></ul>
  4. 4. Implementations & Demos <ul><li>SPW implementation of 801.11b FHSS </li></ul><ul><ul><ul><li>for evaluating the performance of the physical layer under various mobility conditions. </li></ul></ul></ul><ul><ul><ul><li>receiver design with Viterbi equalizer for 2GFSK, 4GFSK, and 8GFSK signals </li></ul></ul></ul><ul><ul><ul><li>Antenna Diversity </li></ul></ul></ul><ul><ul><ul><li>Transmission of video bitstreams </li></ul></ul></ul><ul><ul><ul><li>Effect of packet loss on the recovered video </li></ul></ul></ul>
  5. 5. Multi-hop ad-hoc Networks <ul><li>AODV (Ad-hoc on-demand Distance Vector ) routing. </li></ul><ul><li>DSR (Dynamic Source Routing) </li></ul><ul><li>Sensoria Multi-hop Network (WIN NG 2.0) </li></ul><ul><li>NIST Approach </li></ul>
  6. 6. AODV <ul><li>It provides loop free routes using sequence numbers associated to each route. </li></ul><ul><li>AODV MODULES consists of: </li></ul><ul><li>Rout request, rout reply, routing table, packet resend, packet capture </li></ul>S A B C D RREQ D X To B To C To D RREP S X REER
  7. 7. Sensor Ad-hoc Networking (NIST Demo) AP AP AP AP Sensor Networks iPAQ iPAQ iPAQ 802.11b FHSS IP UDP RTP H.263 802.11b FHSS IP UDP RTP H.263
  8. 8. Video Streaming <ul><ul><li>VIC/RTP package </li></ul></ul><ul><ul><li>VIC on iPAQ (Linux) </li></ul></ul><ul><ul><li>Applied H.263+ compression for low bitrate video conferencing </li></ul></ul><ul><ul><li>Developed H.263 + -based Error resilient video decoding </li></ul></ul><ul><ul><ul><li>Partitioned </li></ul></ul></ul><ul><ul><ul><li>Non-partitioned </li></ul></ul></ul><ul><ul><li>RTP/UDP for low delay video conferencing </li></ul></ul>
  9. 9. PLCP Hdr. 802.11 MAC FCS PLCP Preamble MPDU 802.2 LLC 802.2 SNAP UDP Hdr. RTP Hdr. IP Hdr. H.263 video stream Payload Hdr. Physical Layer Logical Link Layer Network Layer Transport Layer Frame Format for video stream transmitted by RTP/UDP/IP with IEEE 802.11
  10. 10. Solutions <ul><li>Delivering corrupted packets to the higher layer. </li></ul><ul><ul><li>Perform packet-loss corrections: </li></ul></ul><ul><ul><ul><li>Suitable for multicast </li></ul></ul></ul><ul><ul><ul><li>Unsuitable for conferencing </li></ul></ul></ul><ul><ul><li>Perform error resilient video decoding by taking advantage of the RTP packet sequencing to detect lost packets </li></ul></ul>Parity check packet Data packet-k Data packet-1
  11. 11. Video Partitioning Data Splitter IEEE 802.11b FHSS Data Assem. H.263 Video Encoder R R = Bitrate (fixed) S = Splitting Percentage Rate CODEC INDEPENDENT H.263 Video Decoder Packet-H + FEC1 Packet-L +FEC2 Delay MUX DE MUX FEC-2 Decoded FEC-1 Decoded Delay R.S R.(100-S)
  12. 12. Error Resilient H.263 video streaming (SPW Demo) H.263 + encoder Video Input H.263 + decoder IEEE 802.11b FHSS Bitstream re-sync. Video streaming H.263 encoder Video Input H.263 decoder IEEE-802.11b FHSS Splitting & streaming Bitstream combine & re-sync.
  13. 13. Pre-Decoder Design (non-partitioned) video bitstream Bitstream reconstruction Error Concealment Buffer Header Extractor Legal H.263 bitstream Error classifications Self Error Detection Standard Video Decoder Video Display
  14. 14. FY’02 tasks <ul><li>Complete the 802.11b FHSS implementation for field tests </li></ul><ul><li>Performance evaluations in terms of : </li></ul><ul><ul><ul><ul><li>Coverage (indoor/outdoor) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Mobility </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Bandwidth </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Number of nodes </li></ul></ul></ul></ul><ul><li>Further extensions to improve the error resilient decoding of the corrupted bitstream </li></ul>