Error detection and concealment for Multimedia Communications Senior Design Fall 06 and Spring 07.

Error detection and concealment for Multimedia Communications

Senior DesignFall 06 and Spring 07

Outline

• Introduction to multimedia communications

• Overview of JPEG2000

• Error detection and concealment of corrupted regions in the received images due to transmission over a noisy channel.

Multimedia Communication Objectives and Requirements

• Transmitting a large amount of data in real time using the least amount of channel bandwidth

• Transmitted data are robust to channel impairments

Transmission of a 1 second movie clip

Pixel intensity levels 0 to 255 8 Bits512x512 gray level image2.1MB512x512 color image6.3MB1 second movie clip189 MB/secChannel Bandwidth 94.5 MHz

JPEG Compression Based on Discrete Cosine Transform (DCT)

• Data Compression to reduce the transmitted data– Divide Image into Blocks

– Discrete Cosine Transform

– Quantization

– Run length channel coding

77 66 68 67 98 93 79 8179 61 61 71 61 78 88 9479 93 84 64 72 76 95 9497 65 71 75 75 72 95 111120 81 82 76 72 77 78 83150 146 112 83 78 62 91 85156 145 158 125 107 121 95 86158 166 147 146 153 149 129 107

776 46 42 15 -1 5 6 9-165 -90 8 -2 15 0 1 3 82 6 -46 18 -14 -13 2 -6 -37 34 12 5 6 0 4 5 8 -30 -19 21 20 -2 4 2 11 4 -9 -7 -4 -4 9 7 11 12 9 -1 -11 -19 -23 9 0 8 -18 5 -12 -3 13 -1

Quantization

Compression Ratio 10:1

16 11 10 16 24 40 51 6112 12 14 19 26 58 60 5514 13 16 24 40 57 69 5614 17 22 29 51 87 80 6218 22 37 56 68 109 103 7724 35 55 64 81 104 113 9249 64 78 87 103 121 120 10172 92 95 98 112 100 103 99

49 4 4 1 0 0 0 0-14 -7 1 0 1 0 0 0 6 0 -3 1 0 0 0 0 -3 2 1 0 0 0 0 0 0 -1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

5.4816

776 49 * 16 = 784

OriginalImage

CompressedImage

The Drawback of Compression

Images received after transmission over noisy channels

JPEG 2000: Architectural Overview

Level offset

Color TransformRGB->CbCr

Wavelet Transform

Quantization

Region of InterestBlock Coder

Image Sample

Transmission

Channel Coding

Source Coding

Concealment with Edge Information –Transmitted Side Information

Edge image size = 0.32% of original image

Concealment with Edge Information - Received Side Information

Concealment with Edge Information- Edge of Received Image

Concealment with Edge Information- Edge of Received Image

Senior Design Tasks• Learn the JPEG2000 standard.• Search the literature and the internet for the different

methods of error detection and concealment for images transmitted by JPEG2000 standard.

• Design a method to compress the binary image that contain the edge information.

• Design a method to conceal the error by estimating the corrupted pixels using the edge information.

• Evaluate your design by running a simulation of the noisy channel and implementing your design in recovering the corrupted images.

Skills Needed for the Error Detection and Concealment

• Ability to read the literature.• Ability to use Matlab run the simulations of the

proposed algorithms.• Ability to understand the mechanism of wavelet to use

the relationships between coefficients in estimating corrupted pixels.

• Ability to use some probability and statistics to estimate the values of the corrupted pixels.

• Organization, determination, and team work ethic.