CCITT G3/G4 Compression in an SDK bitonal format support in LEADTOOLS

LEADTOOLS supports the CCITT Group3 and Group 4 industry standards for compressing bitonal (1-bit) image data. Both Group 3 and Group 4 encode the source image line by line. The difference between the two schemes is in the way the two standards handle successive scanlines.

In Group 3 1-D, each scanline is encoded independently, whereas in Group 4, scanlines are encoded with reference to the previous one, resulting in improved compression ratios. In Group 3 1-D, a scanline is encoded as a set of runs, each representing a number of white or black pixels, with white runs alternating with black runs. Every run is encoded using a variable number of bits, which can be uniquely identified upon decoding. This means that frequently occurring lengths of run may be encoded very efficiently, while infrequent ones cause the data to grow. For example, a white run of 2 or 3 pixels can be encoded using just 2 bits, while a run of 1000 pixels can be encoded in 25.

Group 4 encoding is more complex as compared to Group 3 encoding. Each scanline is compared with the previous one. Because of this, vertical features in the source image are used to achieve high compression ratios.

There is also a G3 2-D. G3 2-D is a combination of G3 1-D and G4 compression schemes. LEADTOOLS Document and Medical toolkits can keep 1 bit images G4 compressed in memory.

Supported compression formats click below for information on compression formats available in the LEADTOOLS SDKs

LEADTOOLS offers more compression options than any other toolkit on the market. LEADTOOLS supports industry standard and proprietary alternative compression algorithms including:

• ∗JPEG2000
• JPEG
• LEAD CMP
• LZW
• RLE / PackBits
• ZIPLIB
• CCITT G3/G4
• Huffman
• Arithmetic
• ∗JBIG
• ∗LEAD CMW
• ‡LEADTOOLS ABC
• ∗JBIG2
• ∗ABIC

This feature is available in the following products See the list above for more information on which formats are supported in each toolkit.

Pricing Structure

Product	Price	Purchase	Try
LEADTOOLS Multimedia SDK	$595		Free Trial
LEADTOOLS Raster Imaging SDK	$495		Free Trial
LEADTOOLS Raster Imaging Pro SDK	$995		Free Trial
LEADTOOLS Vector Imaging Pro	$1995		Free Trial
LEADTOOLS Document Imaging SDK	†$2495		Free Trial
LEADTOOLS Document Imaging Suite	†$3995		Free Trial
LEADTOOLS Medical Imaging SDK	†$4495		Free Trial
LEADTOOLS Medical Imaging Suite	†$7995		Free Trial

†Marked toolkits require runtime licensing based on the deployment of the application you develop. Several purchase options are available. For more information, please contact oemsales@leadtools.com or call a LEAD sales representative.