Overview
ISO/IEC 16485:2000 - Mixed Raster Content (MRC) defines a standardized, efficient representation for raster-oriented pages that contain a mixture of bi-level (text/line-art) and multi-level (continuous-tone or colour) image data. The standard specifies a layered page model and a data/marker structure for encoding pages so different regions can use the most appropriate compression and spatial/colour resolution without defining new encodings or segmentation methods.
Key topics and technical requirements
- Three-layer page model (base MRC mode): background (contone), mask (bi-level selector), and foreground (multi-level text/graphics). The mask chooses per-pixel whether foreground or background is used.
- Stripe-based page subdivision: pages can be split into horizontal stripes that span the page width. Stripes may be 3-layer (3LS), 2-layer (2LS) or 1-layer (1LS) depending on content, optimizing storage and decode effort.
- Layer-specific coding: any existing ITU-T/ISO encodings may be used for layers (e.g., JPEG (T.81) for multi-level, MMR (T.6) or JBIG (T.82) for bi-level). ISO/IEC 16485 does not introduce new compression algorithms.
- Resolution rules: spatial resolution of foreground/background layers must be integer factors of the mask resolution; mask resolution is defined per page.
- Data format and markers: Start of Page (SOP) and End of Page (EOP) markers, Start of Stripe, and optional marker segments (e.g., layer colour gamut/illuminant) define page and layer parameters and coder choices.
- Transmission order: within each stripe the mask is transmitted first, then background and foreground as applicable.
Applications and who uses it
ISO/IEC 16485 (MRC) is used where mixed-content pages require compact, high-quality exchange and reproduction:
- Document imaging and archiving - long-term storage of scanned multi‑page documents with reduced file size while preserving readable text and photo quality.
- Multifunction printers / scanners - scan-to-email, scan-to-archive workflows that must balance text fidelity and photo compression.
- Facsimile and transmission systems - efficient transmission of mixed documents using established ITU-T codecs.
- OCR and content extraction pipelines - better mask/foreground separation improves OCR accuracy.
- Typical implementers: scanner/MFP manufacturers, imaging software vendors, digital-archive integrators, and standards-compliance engineers.
Related standards
ISO/IEC 16485 references multiple ITU-T/ISO codecs and related recommendations, including:
ISO/IEC 16485 is valuable when you need device-independent, efficient exchange of scanned or rasterized mixed-content pages while leveraging existing image codecs and established facsimile/image standards.