Choose the extraction path for tables, figures and scans¶
Draft outline: not validated
Drafted with AI from official sources on 16 Oct 2026. Do not use on a live system until it is written, dry-run by someone other than the author and signed off (planned 2026-12-04). Author: Kandiah Chockalingam · dry-run: Ranjith · sign-off: Yogeshwaran. Work items: RAG-10-T01, RAG-10-T02, RAG-10-T03, RAG-10-T04.
Catalog point to cover
The catalog stack names GPT-4o vision: name the vision-capable Azure OpenAI model used to describe figures and check its retirement date in the docs.
1. Summary¶
At the start of a document-heavy engagement, or when tables and figures are lost in an existing pipeline.
Risk: Medium (the wrong path drives cost and rework across the whole corpus). Typical duration: 1-2 days including a sample run.
2. When to use and when not to¶
Use it when: At the start of a document-heavy engagement, or when tables and figures are lost in an existing pipeline.
Do not use it when: to be written by the author.
3. What you must know first¶
- The Content Understanding skill is generally available in the 2026-04-01 API, and Microsoft points new skillsets to it
- Content Understanding image descriptions and semantic chunking are preview (2026-05-01-preview)
- The Document Layout skill outputs Markdown and remains supported for existing pipelines
- Document Intelligence Markdown renders tables as HTML and wraps figures in figure tags
- Image verbalisation gives citable text; multimodal embeddings only give visual similarity
- Documents needing more than five minutes of processing time out but are still billed
4. Options¶
Outline of the decision process; the author describes each option.
- Classify the documents: digital text, scanned, table-heavy, diagram-heavy or photos.
- Run the sample through the Content Understanding skill and the Document Layout skill in a sandbox.
- Score table fidelity (cells, merged headers), figure capture and reading order by hand on 20 pages.
- Decide how to handle figures: verbalise with an LLM, embed images, or both.
- Estimate cost per 1,000 pages for each path, including LLM calls for verbalisation.
- Pick the path in the decision table and record the evidence.
- Re-check when a preview feature becomes generally available or pricing changes.
Draft snippet: Content Understanding skill with fixed-size chunking, images and location metadata
{
"skills": [
{
"description": "Analyse a document",
"@odata.type": "#Microsoft.Skills.Util.ContentUnderstandingSkill",
"context": "/document",
"extractionOptions": ["images", "locationMetadata"],
"chunkingProperties": {
"unit": "characters",
"maximumLength": 1325,
"overlapLength": 0
},
"inputs": [ { "name": "file_data", "source": "/document/file_data" } ],
"outputs": [
{ "name": "text_sections", "targetName": "text_sections" },
{ "name": "normalized_images", "targetName": "normalized_images" }
]
}
]
}
Snippets to add:
snippets/skillsets/content-understanding.json: Content Understanding skill with images and location metadata (json)snippets/decisions/extraction-path.md: Extraction path decision table (markdown)snippets/eval/extraction_cost.py: Cost per 1,000 pages estimator (python)
5. Decision table¶
| Situation | Choose | Why |
|---|---|---|
| to be written |
6. Recommended default and when to deviate¶
To be written by the author from the outline above.
7. Known issues and fixes¶
| Symptom | Likely cause | Fix |
|---|---|---|
| Tables split across chunks lose their headers | Fixed-size chunking cuts through tables | Use layout-aware chunking, keep tables whole where possible and repeat headers. |
| Figures produce no useful text | The path extracts images but does not describe them | Add image verbalisation for explanation-rich figures. |
| Unexpected extraction bill | Content Understanding has no free allotment, and timed-out documents are still charged | Cap pages in the sample run and set a budget alert before scaling. |
8. Monitoring and alerts¶
| Signal | Alert when | Action |
|---|---|---|
| Daily cost of the Foundry resource attached to the skillset (Cost Management) | 25% above forecast | Disable the indexer schedule and review the extraction path. |
9. AWS and open-source equivalents¶
On AWS, Amazon Textract (AnalyzeDocument with tables and layout) and Amazon Bedrock Data Automation cover similar extraction. Open-source parsers can run locally for sensitive data but need the same quality tests.
10. Validation record¶
Pending. Planned dry-run scenario: A second engineer runs the decision process on a 50-document sample from a real engagement. Pass: the decision table holds table-fidelity scores, figure coverage and cost per 1,000 pages for at least two paths, and the choice follows from them.