|Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact|
|Full name||CPC (Cartesian Perceptual Compression)|
|Description||The CPC specification defines both a datastream and an associated file format for a compressed, raster (bit-mapped) image, designed for scanned bitonal documents. The method is based on matching of symbols. Cartesian Products claims that files are typically 5 to 20 times smaller than bitonal TIFFs. The compression ratio increases for longer documents.|
|Production phase||Potentially an initial-state or middle-state format for scanned documents; more often used as final-state format.|
|LC experience or existing holdings||None|
|LC preference||For instances where bitonal images reflect content adequately, open standards, e.g., TIFF_G4, are preferable.|
|Disclosure||Proprietary compression scheme. Cartesian Products makes available APIs (application programming interfaces) to facilitate development of software using the scheme.|
|Documentation||No specification found. An overview is at http://www.cartesianinc.com/Tech/tech-overview.html|
Requires plug-in or viewer for use. Various online document supply services that serve specialized audiences use CPC files for delivery, expecting recipients to download and install the plug-in or viewer. Cartesian Inc. provides a page of clients at http://www.cartesianinc.com/General/clients.html; however, the date on this page indicates that it has not been updated since 2007.
Cartesian Inc. provides several viewers and compression tools. Viewers and decompression are free. Compression requires a purchased license after an evaluation allowance. Two APIs are available as software development kits at http://www.cartesianinc.com/Tech/API/. As of January 2014, the pages describing compression tools and viewers indicate updating in 2013 and 2014. A CPC viewer has been released for the iPad.
|Licensing and patents||Patent filed in 1991 and issued in 1994 (#5,303,313). Treated in proprietary fashion.|
Depends upon algorithms and tools for decompression to read; requires sophistication and access to documentation to build tools.
Two APIs are available as software development kits at http://www.cartesianinc.com/Tech/API/.
|Technical protection considerations||None|
|Normal rendering||Limited to bitonal images.|
|Clarity (high image resolution)||Limited to bitonal images. Intended primarily for documents.|
|Color maintenance||None. CPC is limited to bitonal images.|
|Support for vector graphics, including graphic effects and typography||None.|
|Functionality beyond normal rendering||None.|