Electronic Filters
Real-world signals contain wanted and unwanted information. Therefore, some kind of electronic filtering technique must separate the two before processing and analysis can begin.
http://www.freqdev.com/filters.html

Singlefin
iPrism - Monitor and Report on Internet use. iPrism is the #1 Web filtering appliance. iPrism utilizes iGuard the top url filtering database for internet content filtering.
http://www.singlefin.net

CyberGuard
ICSA and NSA certified Unixware and NT-based filtering firewall. Offers static packet filtering, dynamic packet filtering (stateful inspection) and proxy gateway (smart proxies).
http://www.cyberguard.com/

Photographic Imaging Technique
PIT utilizes readily available computer software and hardware to visually document underwater cultural and biological resources. Examples of this technique.
http://www.indiana.edu/~scuba/pit.html

Lung Nodule Detection Using Template-Matching Technique - unpublished manuscript
Description of a simple technique for computer-aided diagnosis of lung nodules in chest radiographic images.
http://paginas.fe.up.pt/~ee98171/apsi/

Visual Dorp Filter
DORP - Home of Object Oriented Filtering for Visual FoxPro and SQL developers.DORP-VDF objects are set of date-centric filtering objects and provided to help speed the process of filtering application development.VCX library for VFP8,VFP9 development views and reports.Advice, tips, sample code, downloads.
http://www.dorp-vdf.com

Safer Path Internet
Dialup access with web filtering or add filtering to your existing connection.
http://www.saferpath.com/

SpamEater Pro
Email filtering system that can automatically receive periodic updates to its filtering rules.
http://www.hms.com/spameater.asp

NetMail
Email client. Full-featured e-mail client designed for e-business
http://www.softwarea.com/netmail.htm

HWG Filtering FAQ (Windows, Mac, Unix)
The HTML Writers' Guild's FAQ sheet about mail filtering systems (multiple platforms)
http://www.hwg.org/resources/faqs/filterFAQ.html