Borko Basarić - Praktična uputstva za zaštitu od jonizujućeg ...
Multimedia Projects Our Experience Research Projects NSF Multimedia Laboratory at Florida Atlantic...
-
Upload
tyrone-turner -
Category
Documents
-
view
217 -
download
0
Transcript of Multimedia Projects Our Experience Research Projects NSF Multimedia Laboratory at Florida Atlantic...
Multimedia ProjectsOur Experience
Research Projects
NSF Multimedia Laboratory at Florida Atlantic University
(1995-2001)
Director Dr. Borko Furht
ProjectsContent-Based Image Retrieval Using Relevance
Feedback (Oge Marques) IP Simulcast - An Innovative Video and Audio
Broadcasting Technique Over the Internet (Ray Westwater and Jeff Ice)
XYZ Video Encoding Technique (Ray Westwater & Joshua Greenberg)
An Innovative Motion Estimation Algorithm for MPEG Codec (Joshua Greenberg)
A Fast Content-Based Multimedia Retrieval Technique (P. Saksobhavivat)
Interactive Progressive Encoding System (Joe Celi)
Internet Broadcasting or WebcastingBroadcasting multimedia data (audio
and video) over the Internet - from a server (sender) to a large number of clients (receivers)
Applications include: radio and television broadcasting
real-time broadcasting of critical data distance learning videoconferencing database replication electronic software distribution
Broadcast Pyramid Applied in IP Simulcast
SERVER
Client 1
Client 2
Client 3
Client 2
2
Client 4
Client 5
Client 6
Client 9
Client 10
Client 11
Client 12
Client 13
Client 8
Client 14
Client 7
IP Simulcast - An Innovative Technique for Internet Broadcasting
IP Simulcast reduces the server (or sender) overhead by distributing the load to each client (or receiver)
Each receiver becomes a repeater, which rebroadcasts its received content to two child receivers
The needed network bandwidth for the server is significantly reduced
Characteristics of IP Simulcast
It is a radically different model of digital broadcast, referred to as repeater-server model
The server manages and controls the interconnection of repeaters
Each repeater not only plays back the data stream, but also transmits the data to two other repeaters
IP Simulcast provides guaranteed delivery of packets, which is not the case with IP Multicast
Product: AllCastwww.allcast.com
Broadcasting Tree
Once the AllCast Broadcaster is configured, many users can connect to hear/view content. The bandwidth usage is distributed across the participants, as illustrated by the dynamic, self-healing dissemination tree shown in the AllCast main window.
Microsoft Media Player with AllCast Plug-in
•Users can connect to a broadcast using the Microsoft Windows Media Player together with a small, seamlessly integrated AllCast Plug-in. •The plug-in enables the Windows Media Player to participate in peer-to-peer broadcasts.
XYZ - New Video Compression Technique
The XYZ video compression algorithm is based on 3D Discrete Cosine Transform (DCT)
It provides very high compression ratios and excellent video quality
It is very suitable for real-time video compression
Forming Video Cube for XYZ Compression
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
Frames 0 1 2 3 4 5 6 7
8X8X8videocube
Block Diagram of the XYZ Compression
Forward3-DDCT
Quantizer EntropyCoder
QuantizingTables
HuffmanTable
VideoCube
Compressedvideosequence
Key Encoding Equations Both encoder and decoder are symmetrical, which makes
the algorithm suitable for VLSI implementation
Fuv w CuCvCw f x y z
x u y v z w
zyx
( , , ) , ,
cos cos cos
0
7
0
7
0
7
2 1
16
2 1
16
2 1
16
(4.1)
FuvwFuvw
Quvwq ,,,,
,,
(4.3)
XYZ Versus MPEGVideo
CompressionTechnique
CompressionRatio
NormalizedRMSError
ExecutionTime [min]
(8 frames, 320x240)
XYZ(QT1)
34.5 0.079 6.45
XYZ(QT2)
57.7 0.097 6.45
XYZ(QT3)
70.8 0.105 6.45
XYZ(QT4)
101.7 0.120 6.45
XYZ(QT5)
128.1 0.130 6.45
MPEGLogarithmic Search andError Correction
11.0 0.080 21.35
MPEGExhaustive Search andError Correction
15.6 0.080 163.0
MPEGLogarithmic Search andNo Error Correction
27.0 0.140 21.35
MPEGExhaustive Search andNo Error Correction
32.9 0.125 163.0
Complexity of Video Compression Techniques
CompressionAlgorithm
EncoderComplexity
DecoderComplexity
TotalComplexity
H.261/H.263 970 200 1,170MPEGNo B Frames
750 100 850
MPEG70% B Frames
1,120 120 1,240
XYZ 240 240 480
XYZ Versus MPEG
Original
MPEGCr=11,NRMSE=0.08
MPEG, Motion Est. onlyCr=27, NRMSE=0.14
XYZCr=45, NRMSE=0.079
Examples of XYZ Compression
Original
XYZ-compressedCr=51
Examples of XYZ Compression
OriginalXYZ-compressedCr=110
Sensitivity of the XYZ Algorithm to Various Video Effects
Movie ClipVideo Effect
CompressionRatio
Normalized RMSEError
Dick TracyTypical Motion
34.5 0.079
Interview with theVampireCamera Break
32.5 0.087
Interview with theVampireCamera Panning
26.1 0.085
Total RecallCamera Panning
17.5 0.049
Total RecallCamera Zoom
23.9 0.042
InterceptorFast Motion
26.0 0.025
Characteristics of XYZ Video CompressionXYZ gives significantly better
compression ratios than MPEG for the same quality of video
For similar compression ratios, XYZ gives much better quality than MPEG
XYZ is faster than MPEG (lower complexity)
XYZ is simple for implementation
Applications of the XYZ
Interactive TV and TV set-top boxesTV phoneVideo broadcasting on the InternetVideo-on-demand applicationsVideoconferencingWireless video
TV Phone Videophone is a box on the top of TV with a small Videophone is a box on the top of TV with a small
camera, modem, and video/audio codec.camera, modem, and video/audio codec.
Videophone Videophone
Conventionaltelephone network
TV set TV set
Design of the TV Phone
VIDEOPHONE
TV
Video/audio capture and compression
Video-in
Video/audio out
Video/audio out
Video/audio in
Modem Telephone lines
User'scontrol panel
Video/audiodecompressionand conversion to TV format
VLSI chipsimplement XYZ algorithm
Camera
A Fast Content-Based Multimedia Retrieval Technique
Two main approaches in indexing and retrieval of images and videos
Keyword-based indexing and retrieval
Content-based indexing and retrieval
Keyword-Based Retrieval and Indexing
Uses keywords or descriptive text, which is stored together with images and videos in the database
Retrieval is performed by matching the query, given in the form of keywords, with the stored keywords
This approach is not satisfactory - the text-based description is incomplete, imprecise, and inconsistent in specifying visual information
New Algorithm for Similarity-Based Retrieval of Images
Images in the database are stored as JPEG-compressed images
The user submits a request for search-by-similarity by presenting the desired image.
The algorithm calculates the DC coefficients of this image and creates the histogram of DC coefficients.
The algorithm compares the DC histogram of the submitted image with the DC histograms of the stored images.
Histogram of DC Coefficients for the Image “Elephant”
Comparison of Histograms of DC Coefficients
Example of Similarity-Based Retrieval Using the DC Histograms
Similarity-Based Retrieval of Compressed Video
Partitioning video into clips - video segmentation
Key frame extractionIndexing and retrieval of key frames
DC Histogram Technique Applied for Video Partitioning
0
5
10
15
20
25
30
35
40
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Frame number
NSD
x 1
00 [%
]
Example of Similarity-Based Retrieval of Key Frames Using DC Histograms
Interactive Progressive Encoding System
Users submit requests for imagery to the image database via a graphical user interface
Upon an initial request, a DCT image (version of the image based on DC coefficients only) is transmitted and reconstructed at the user site.
The user can then isolate specific regions of interests within the image and request additional levels of details.
Band Transmission in Interactive JPEG System Based on Spectral Selection
All blocks of the image
Amplitude of Coefficients Blocks of the selected region of the image
Band-1 Band-2 Band-3 Band-4
DC AC1 AC2 AC3 …… AC6 AC7 ………. AC63
Transmission
Prototype System - IPES and Experimental Results
Original image “Airport”
Interactive Progressive Transmission in Four Scans
Selection of Two Regions
Cumulative Number of Transmitted Bits
0
200
400
600
800
1000
1200
1400
1600
1800
2000
1 2 3 4
Scans
Cum
ulat
ive
tran
smitt
ed b
its [K
bits
]
Whole Image
1 Region
2 Regions
Extracted Images From a Group of Images
Applications
Retrieval and transmission of complex images over low bandwidth communication channels (image transmission over the Internet, real-time transmission of medical images)
Archiving and browsing visually lossless image databases (medical imaginary, space exploration and military applications)
Content-Based Retrieval
Large, complex, and ever growing, distributed, mostly unstructured, multimedia repositories
Three ways of retrieving multimedia information:– Free browsing (inefficient, time-consuming, doesn’t
scale well)– Text-based retrieval (relies on metadata, time-
consuming, subjective)– Content-based retrieval (requires intelligent
interpretation of the contents)
Design of MUSE System
Image Analysis
Image Feature Extraction-Color-Shape-Texture
Image Representation & Feature Organization
ImageArchive
User
GUI-Image selection-Result viewing
Probability recalculation & candidate ranking
Feature ExtractionSimilarity comparison
Interactive learning& Display update
Off-line Online
Query By Example
Example image
Best result
Similarity Score [0,1]
Relevance Feedback
Good
Bad
Neither
Relevance Feedback - Next
Technology Behind the MUSE System Feature extraction
Extraction of relevant image features impacts the overall performance of the system.
MUSE uses:– color-related features (color histograms, color
space partitioning and/or quantization, color moments, color coherence vectors)
– texture-related features (Multiresolution Simultaneous Autoregressive Model - MSAR)
– frequency-related features (DFT, DCT)
Technology Behind the MUSE System Bayesian formulation
MUSE is based on a Bayesian framework for relevance feedback.
During each iteration of a MUSE session, the system displays a subset of images from its database, and the user takes an action in response, which the system observes.
Based on the user’s actions, the probability distribution over possible targets is refined. (Most systems refine the user’s query)
The best candidates are then displayed back.