Cartesian Perceptual Compression (abbreviated CPC, with
filename extension .cpc) is a proprietary
image file format. It was designed for high compression of black-and-white
raster Document Imaging Document imaging is an information technology category for systems capable of replicating documents commonly used in business. Document imaging systems can take many forms including microfilm, on demand printers, facsimile machines, copiers, multif ...
for archival scans.
CPC is
lossy
In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size ...
, has no
lossless
Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statistic ...
mode, and is restricted to bi-tonal images. The company which controls the patented format claims it is highly effective in the compression of text, black-and-white (halftone)
photographs, and line art. The format is intended for use in the web distribution of legal documents,
design plans, and geographical plot maps.
Viewing and converting documents in the CPC format currently requires the download of proprietary software. Although viewing CPC documents is free, as is converting CPC images to other formats, conversion to CPC format requires a purchase.
JSTOR, a United States-based online system for archiving academic journals, converted its online archives to CPC in 1997. The CPC files are used to reduce storage requirements for its online collection, but are temporarily converted on their servers to GIF for display, and to PDF for printing. JSTOR still scans to TIFF G4 and considers those files its preservation masters.
See also
*
Image file formats
An Image file format is a file format for a digital image. There are many formats that can be used, such as JPEG, PNG, and GIF. Most formats up until 2022 were for storing 2D images, not 3D ones. The data stored in an image file format may be ...
External links
The company's websiteAdditional technical information about the format
Library of CongressAnalysis of format by the LoC.
RLG DigiNews Vol. 7 No. 2Comparison of rivals to TIFF for Document Imaging purposes
Graphics file formats
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