Mrc High Compression Scanning - Xerox 4112 User Manual

• JPEG: Joint Photographic Experts Group - A compression method that is commonly used for
images. For Grayscale and Color images, JPEG is used to compress the image. JPEG
resolution depends on system settings. See the System Administrator Guide or contact your
system administrator for additional details.
Note
Lossless data compression allows the same original data to be reconstructed from the
compressed data. Lossless compression is used for data and text files. Lossy data compression
does not produce exact reconstructions. Audio and video files often use lossy compression.

MRC High Compression Scanning

MRC, or Mixed Raster Content, is a compression model that separates an image into three
different layers: foreground, background, and mask. Each layer is compressed separately using
the most appropriate type of compression for that data type and is later uncompressed and
recombined based on the mask layer to restore the original image.This compression model is
available only when using the PDF Scan Kit.
As an example, consider a document with text, photographs and graphical elements. Using the
MRC High Compression model we might place photographic elements in the Background layer,
colored graphical elements (including text color) in the Foreground layer, and text shapes (or
other similar high frequency, high contrast elements) in the Mask layers. Since text carries visual
information at high contrast and spatial frequency, it can be encoded as 1 bit per pixel at 600
spi. The values of 0 and 1 for the Mask layer indicate which of the two other layers should be
used for reconstruction of the composite image.
In contrast to text, the accurate communication of photographic and colored graphical visual
information requires fewer pixels per inch (lower spatial frequency), but requires more bits per
pixel. To compress the image, we would use a binary and typically lossless algorithm, e.g., MMR,
while the Background and Foreground layers would be compressed using a continuous tone,
and typically, lossy algorithm, e.g., JPEG.
Using MRC High Compression will generally produce a smaller file size than using one of the
other compression models. You can use MRC Compression on its own or with the other
compression models for additional compression scenarios.
Note
The following conditions should be considered when using the MRC High Compression feature:
• MRC High Compression is not available for Color Scanner Kit Black & White jobs.
• MRC High Compression is supported for 200 or 300 dpi scans, only.
• When MRC High Compression is designated, document type options are not available. The
device automatically scans the document in the Text/Photo mode.
• Photographic paper scanning is not supported with the MRC High-Compression feature.
• PDF v1.3 is output in the MRC High Compression feature, and documents can be opened by
Acrobat 4.x, or later. When JBIG2 is used for the compression method of the mask image,
PDF v1.4 is output.
Xerox 4112/4127 Copier/Printer
User Guide
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