How are deep images merged, made tidy and flattened to a flat image according to the OpenEXR deep-pixel document, including how alpha and colour are combined?
The document defines merging two deep images as concatenating sample lists; flattening needs a tidy image (sorted and non-overlapping): split partially overlapping samples, merge coincident ones (alpha = 1-(1-a_i)(1-a_j)), sort, then composite front to back with over. Volume opacity follows 1-(1-alpha)^x so splitting preserves total opacity, and the flattened depth is not uniquely defined. Files need not be tidy.
The document defines merging two deep images as concatenating sample lists; flattening needs a tidy image (sorted and non-overlapping): split partially overlapping samples, merge coincident ones (alpha = 1-(1-a_i)(1-a_j)), sort, then composite front to back with over. Volume opacity follows 1-(1-alpha)^x so splitting preserves total opacity, and the flattened depth is not uniquely defined. Files need not be tidy.
Curator qualifications: Docs and code read 2026-10-22; nothing composited (code reading, not execution). Numeric stability appendix and thick-layer thresholds not re-transcribed.
Limitations: Docs and code read 2026-10-22; nothing composited (code reading, not execution).
Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.
Structured fields
{
"citations": [
{
"url": "https://github.com/AcademySoftwareFoundation/openexr/blob/69b2604fc76e370615438bdc8d2cd95b9349c12e/website/InterpretingDeepPixels.rst",
"note": "InterpretingDeepPixels.rst L238-277, L456-508"
}
]
}Evidence claims
- [sourced_fact] The document defines merging two deep images as concatenating sample lists; flattening needs a tidy image (sorted and non-overlapping): split partially overlapping samples, merge coincident ones (alpha = 1-(1-a_i)(1-a_j)), sort, then composite front to back with over. Volume opacity follows 1-(1-alpha)^x so splitting preserves total opacity, and the flattened depth is not uniquely defined. Files need not be tidy. · locator: InterpretingDeepPixels.rst L238-277, L456-508 source
Rights
| component | license | hosting | redistribution | modification | training | Evidence and notes |
|---|---|---|---|---|---|---|
| documentation | unknown | permitted | permitted | unknown | unknown | Applies to this original summary only, not to the cited sources. |