Post on 12-Sep-2021
Image and Video Filtering on Internet Networks
Airlangga Cahya Utama7406.040.006
Background
! Internet as a big source of information
! Not all information is safe to consume
" Example: war, sex, and drugs
! Porn is one of internet problem
! Filter using text based or domain based is difficult to maintain
! SOLUTION: Image or video based filtering
References! Matthew Turk, Alex Pentland, Eigenfaces for
Recognition, 1991
! Muhammad Fatoni Ashariyanto, Rudy Cahyadi Hario Pribadi, Dadet Pramadihanto, Sistem Seleksi Gambar Khusus Dewasa Melalui Web Proxy Menggunakan Image Processing, 2007
Capture Packet
! We can capture packed on computer used to access internet (gateway / hop).
" Transport layer
! nCap, pktd, libpcap
" Application layer
! Proxy (icap protocol)
Transport Layer
! Pro
" Fast
" Didn't need another daemon running
! Cons
" Complicated
" Parsing tcp/ip packet manually
" Combine tcp/ip packet manually, and maintain connection state
Application Layer - ICAP
! Pro
" Simple (based on HTTP)
" Only need to implement ICAP parser
" Can leverage proxy cache capabilities
! Cons
" A bit slow (request is redirected to proxy, more hops)
" Requirement to run proxy daemon
ICAP
! Internet Content Adaptation Protocol (RFC 3507).
! Protocol build to support content adaptation on web-proxy.
! Based and using HTTP format.
! Usage: Virus detection, HTML to WML converter, Content optimizer (image size/text compression), Porn Detection
Squid - ICAP Support
! Squid 3 have built-in ICAP support.
! Squid 3 is already reach mature/stable release
! Squid 2 must be hacked to support ICAP
ICAP Data Example! RESPMOD icap://127.0.0.1:10000/ ICAP/1.0
! Host: 127.0.0.1:10000
! Encapsulated: req-hdr=0, res-hdr=386, res-body=633
! Allow: 204
! GET http://127.0.0.1/logoITS.jpg HTTP/1.1
! Host: 127.0.0.1
! User-Agent: Mozilla/5.0 Gecko/20100611 Firefox/3.6.4
! HTTP/1.1 200 OK
! ???JFIFHHC??(1#%(:3=<9387@H\N@DWE78PmQ
System Overview
ICAP data from Proxy
Image Detection
Image Format Detection
! Parse header data (xx first byte data) from ‘intercepted’ content.
! Why?
" Some server provide dynamic content and tell browser via MIME HTTP Header.
! Example: file image but extension type php
" MIME content can’t be trusted either
! Example: downloadable content
Image Header Example
! PNG File
" 89 50 4E 47 0D 0A 1A 0A – PNG Header
! JPEG File
" FFD8 – Start of image marker
" And followed by another marker such as FFE0, FFDB, FFC4, etc…
Skin Filtering - Peer Model
Requirement:
R>95 && G>40 && B>20 && (max(R,G,B)-min(R,G,B))>15 && abs(R-G)>15
R>G && R>B && G>BR<(G+150) && R<(B+150) && G<(B+150)
Result Example of Skin Filtering
Method Used to Detect Object
! Haar Wavelet
" Rainer Lienhart, Alexander Kuranov, Vadim Pisarevsky
! Eigenfaces
" Matthew Turk, Alex Pentland
Object Detection Haar Wavelet
Haar Wavelet
Eigenfaces – Training Algorithm! Concate Images
! Find mean
! Find image mean
! Build A from image mean
! Find matrix covariant C
! Find eigenvector from C
! Keep some eigenvector with the highest eigenvalue
Eigenfaces – Training Data
Eigenfaces – Compare Algorithm! Find weight, from
calculation with eigenvector.
! Projection image to facespaces.
! Measure distance between image and facespaces.
! Compare distance and threshold
Scanning Method
! Take a 64x64 slice from image
! Compare it
! Move to the next slice
! If all slice checked, resize image to smaller one with nearest neighborhood method
! Move distance is 24 pixel, scale down is 15% ratio.
Responding to Proxy
Networking Result
Networking Result
Result (Detected - Change Image)
Result (Not Detected)
Result (Detected and Not-Detected)
Object Detection
Testing
! 200 positive image
" Variation of size
" Variation or colour skin
" All frontal and contain breast object
! 410 negative image
" Variation of size
" Variation of image object
! page banner, thumbnail, and people
Detection Rate
Detection Rate
Performance
Conclusion
! ICAP filtering method is proved working corectly.
! Eigenfaces speed is comparable to Haar Wavelet.
! Eigenfaces detection is worse than Haar.
! Buffering technique is working only for non-streaming website.
Image and Video Filtering on Internet Networks
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