fix(dicomImageLoader): normalize stored pixel bits

[daker]

Context

Mask unsigned pixels to Bits Stored before range calculation. Use High Bit to locate the stored field and preserve signed values. Fix rendering when unused upper bits contain nonzero data.

Fixes #781

Changes & Results

Testing

Checklist

PR

• [] My Pull Request title is descriptive, accurate and follows the
  semantic-release format and guidelines.

Code

• [] My code has been well-documented (function documentation, inline comments,
  etc.)

Public Documentation Updates

• [] The documentation page has been updated as necessary for any public API
  additions or removals.

Tested Environment

• [] "OS:
• [] "Node version:
• [] "Browser:

Summary by CodeRabbit

• Bug Fixes

  • Improved DICOM image pixel decoding for unsigned and signed pixel data.
  • Correctly applies stored-bit ranges and High Bit metadata, improving image values when pixel data uses nonstandard bit layouts.
  • Preserves already-normalized data and safely handles invalid pixel metadata.

• Enhancements

  • Image frame metadata now includes High Bit information for more accurate pixel interpretation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: c146eddb-92a8-4dc8-9dc7-0660b8114cd8

📥 Commits

Reviewing files that changed from the base of the PR and between 7034957 and 90f7fc1.

📒 Files selected for processing (5)

• packages/core/src/types/IImageFrame.ts
• packages/dicomImageLoader/src/__tests__/normalizeStoredPixelData.spec.ts
• packages/dicomImageLoader/src/decodeImageFrameWorker.js
• packages/dicomImageLoader/src/imageLoader/getImageFrame.ts
• packages/dicomImageLoader/src/shared/normalizeStoredPixelData.ts

Included review availability: Your plan includes up to 4 reviews per rolling hour; 2 remain after this review.

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📝 Walkthrough

Walkthrough

The change adds optional HighBit metadata, centralizes stored pixel normalization, applies it during decoded-pixel post-processing, and adds coverage for masking, shifting, sign extension, and unchanged data.

Changes

Decoded pixel normalization

Layer / File(s)	Summary
HighBit metadata contract packages/core/src/types/IImageFrame.ts, packages/dicomImageLoader/src/imageLoader/getImageFrame.ts	The ImageFrame type accepts highBit, and image-frame creation includes the DICOM HighBit value.
Stored pixel normalization packages/dicomImageLoader/src/shared/normalizeStoredPixelData.ts	The shared function validates metadata, masks and shifts stored bits, and sign-extends signed values in place.
Decoder integration and validation packages/dicomImageLoader/src/decodeImageFrameWorker.js, packages/dicomImageLoader/src/__tests__/normalizeStoredPixelData.spec.ts	Decoded-pixel post-processing uses the shared normalizer. Tests cover unsigned masking, signed sign extension, HighBit extraction, and unchanged data.

Estimated code review effort: 3 (Moderate) | ~15 minutes

Merge Risk: ⚪ Minimal · up to 90f7f

No actionable merge-blocking risk remains; the PR is merge-ready after normal checks and review.

Possibly related PRs

• cornerstonejs/cornerstone3D#2611: Both changes modify decoded pixel handling in packages/dicomImageLoader.

Suggested reviewers: sedghi

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description explains the bug and links issue #781, but it omits testing details and leaves all checklist items unchecked.	Add concrete testing steps and tested-environment details, then mark each applicable checklist item as complete.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the stored-pixel normalization fix and follows the repository's semantic-release format.
Linked Issues check	✅ Passed	The changes address issue #781 by normalizing stored bits, using HighBit, preserving signed values, and adding targeted tests.
Out of Scope Changes check	✅ Passed	The code, metadata update, integration change, and tests are directly related to correcting DX pixel rendering described in issue #781.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[daker]

@jbocce can i have a review?