Control Settings Reference
LuraTech’s flagship product, LuraWave, provides a revolutionary, platform-independent, wavelet-
based compression format (.lwf). LuraWave’s analyzing wavelet filter allows a lossless
compression at low compression ratios and lossy compression at higher ratios. LuraWave’s lossless
image compression significantly outperforms that of comparable techniques, like LZW and TIFF.
Compared to conventional compression methods like JPEG, LuraWave maintains maximum, user-
defined image quality using a lossless-to-lossy compression scheme. LuraWave has 5:1 lossless
(guaranteed pixel identity) compression and 1:100 lossy compression without any apparent
artifacts. But users can select compression ratios up to 1:200.
Images in standard digital formats (for example, TIFF, BMP, PPM, JPEG) can be easily converted
to the LuraWave format through:
• LuraWave plug-ins, available online for applications like Adobe Photoshop, Jasc
Paintshop Pro, Netscape and Microsoft browsers, Cumulus, and Macromedia Director.
• Standalone solutions, like LuraWave SmartCompress, which can compress images to less
than 0.5 percent of their original size, facilitating the sharing of high-quality images
quickly and easily through e-mail or personal Web sites. The desired image size is
specified by the user, making SmartCompress extremely valuable to users with limited
bandwidths or storage.
• Software development kits (C-SDK, OCX-SDK).
LuraWave allows you to use a wide variety of new, wavelet-based, compression techniques.
• Fast compression and decompression. LuraWave compression is an extremely fast
wavelet-based image compression technique. Compression and decompression consume
about the same computation time.
• Excellent image quality at high compression rates.
• A choice of lossless or lossy image compression.
• A user-specified compression rate. Size-dependent compression control is embedded in
LuraWave, while other compression techniques dictate file size by the content of the
image and can vary from that of the user’s desired file size. Of course, LuraWave also
grants you the option to compress an image by setting the desired quality, rather than file
• Elimination of JPEG-like blocking artifacts. JPEG uses the inherently lossy Discrete
Cosine Transform compression algorithm, which compresses an image in partitioned
“tiles.” LuraWave uses a special Discrete Wavelet Transform image analyzing method that
results in improved image quality by performing Discrete Wavelet analysis over the whole
image without tile partitioning, so there are no residual “blocking” artifacts.
• Quicklook generation and scale image reconstruction based on embedded coding
Overview ImageGear PDF • 1
• Scaled image reconstruction means the whole image can be reconstructed by only small
fractions of the compressed data source. That is, by 1 percent, 10 percent, 50 percent and
so on (the quality of the reconstructed image being proportionate to the amount of
The name of the ImageGear LuraWave plug-in is IGLura.dll. For information on using the newly
available ImageGear plug-ins in your application, see the “ImageGear Plug-Ins” section in Chapter
One of the main ImageGear manual.
Supported Save Compressions
The LuraWave codec has two compression modes, progressive and baseline.
In the progressive or embedded mode of the codec, the whole image is compressed at once. Then,
image data is ordered hierarchically, with information describing the most important image features
(sharp edges, large areas) is near the head of the file; less important information is near the end.
This makes it possible to preserve the most important file information, even if the file is arbitrarily
cut off. During transmission over a slow network connection, a rough version of the image can be
reconstructed before the transmission is even completed. As a result, this mode is especially
suitable for pictures in networks (like the Internet). However, only relatively small pictures should
be compressed in this mode (up to 1000 by 1000 pixels, depending on the computer’s memory
configuration) because the full image is held in memory during encoding.
Very large images should be compressed in the baseline mode. In this mode, stripes consisting of
several pixel rows are compressed sequentially. Only one stripe is held in the memory at a time, so
less memory is used. The hierarchical structure of the compressed image file is partially lost. A
section in the compressed file contains the hierarchically ordered information of only one stripe.
To save an image with LuraWave compression, assign a defined Save constant to the lFormatType
parameter of IG_save_file (DLL), or to the SaveFormat property (ActiveX). These constants are
defined in your gear.h (DLL) and gear.bas (ActiveX) files.
To Save As: Use:
8g, 16g, 24 bpp images using the IG_SAVE_LURAWAVE
LuraWave compression method
2 • ImageGear PDF Supported Save Compressions
Image Control Options
Control Option Value Description
IG_CONTROL_LURAWAVE_ Any non-negative value Compression coefficient. If zero,
QUALITY lossless compression method will
IG_CONTROL_LURAWAVE_ IG_LW_SMODE_ Compression mode
Control Settings Reference
Data Type: DOUBLE
This control option sets compression coefficient. If zero, lossless compression method will be used.
For example, if you set 2 for this control option then size of the output file will be less by half then
size of the original uncompressed image
Valid Values: Any non-negative value.
Default Value: 10.0
Gear1.ImageControlSet IG_CONTROL_LURAWAVE_QUALITY, 40.0
Data Type: INT
Image Control Options ImageGear PDF • 3
This control option sets compression mode.
Default Value: IG_LW_SMODE_EMBEDDED
4 • ImageGear PDF Control Settings Reference
Baseline compression 2
Control Options 3
Control Settings 3
Image Control Options 3
Progressive compression 2
quality (setting) 3
Save Compressions 2
Save compressions 2
scan mode 3
Settings Reference 3
Index ImageGear PDF • 5