Working with MRC Bitmap
The LEADTOOLS MRC (Mixed Raster Content) Control enhances LEADTOOLS input/output functionality by adding support for color documents containing mixed image and text components.
The advantage of the MRC model is that optimal compression methods can be selected for the various image and text components of documents, resulting in both high compression factors and high detail retention. Image and text components may be mixed on the same page.
The MRC compression breaks an image into three kinds of layers: foreground, background, and mask layers, each of which is compressed separately. These layers can be uncompressed and combined to restore the original image.
A foreground layer contains color data for the text and line art, and may also contain photographic or continuous tone color data. The background layer generally contains low-resolution color image data, such as a background image, a wash or other pattern that would have text overlaid on it. The mask layer or the selector layer that controls the process of image regeneration contains binary image data that is high spatial resolution, such as text and line art. This layer is used for drawing the corresponding foreground layer where the selector value is 1 and drawing the corresponding background layer where the selector value is 0. (For example: a high-resolution color font can be represented using significantly less space, since the color information is stored at a lower resolution.)
The segmentation can be performed automatically with the option to optimize it manually or it can be done only manually. The applicable segment types are text and image. The user can set up which compression will be applied for each area type. The compression for 1-bit schemes can be Fax G3 1D, Fax G3 2D, Fax G4 or JBIG, the compression for images can be JPEG for T44 standard format, and can be JPEG, LEAD CMP for LEAD proprietary T44 format. The user can also set up the quality parameters of some of these compressions.
|
Note: |
The characteristics of individual images differ greatly and not every image compresses well as mixed raster content. |
For more information refer to: