2003年の今日、米ユニシス社が所有している画像技術のGIF（Graphic Interchange Format）フォーマットに関する米国の特許が失効しました。1983年6月20日に出願されたこの特許は、「高速データ圧縮及び解凍」 に関するもので、1985年にすでに米国で登録になってい ...

LZW compression is the compression of a file into a smaller file using a table-based lookup algorithm invented by Abraham Lempel, Jacob Ziv, and Terry Welch. Two commonly-used file formats in which ...

「LZ77／LZ78」アルゴリズムを改良して生まれたLZWは、1983年6月に出願、1985年に特許として登録されています。 もともとSperryがその権利を保有していたのですが（WelchはSperryの社員でしたので）、SperryがBurroughsと合併して生まれたUnisysがその権利を引き継ぐことになりました。

A patent underlying one of the Web's most popular graphics formats is set to expire later this month, raising the question of whether a rival, open-source format, created as a royalty-free alternative ...

Compression is the science of making data representations smaller, in order to decrease the data's bandwidth and storage requirements. Compression applications are everywhere: in computers (WinZip and ...

The committee that develops the JPEG image compression standard has refuted a claim by a U.S. company to own a patent that gives it exclusive rights to the algorithm underlying JPEG. If it were proven ...

A patent underlying one of the Web's most popular graphics formats is set to expire later this month, raising the question of whether a rival, open format, created as a royalty free alternative, will ...

The GIF format uses the LZW compression algorithm, which was patented by Unisys, and publishers of applications that read and write GIF87a and GIF89a images were ...

In the last two columns (Part 1, Part 2), we contrasted a number of compression tools that you might use to free up disk space on your systems. In comparing compression utilities, the most important ...