axiom-vision

SKILL.md

Computer Vision

You MUST use this skill for ANY computer vision work using the Vision framework.

Quick Reference

Symptom / Task
Reference

Subject segmentation, lifting
See skills/vision-framework.md

Hand/body pose detection
See skills/vision-framework.md

Text recognition (OCR)
See skills/vision-framework.md

Barcode/QR code detection
See skills/vision-framework.md

Document scanning
See skills/vision-framework.md

DataScannerViewController
See skills/vision-framework.md

Structured document extraction (iOS 26+)
See skills/vision-framework.md

Isolate object excluding hand
See skills/vision-framework.md

Vision framework API reference
See skills/vision-ref.md

Visual Intelligence integration (iOS 26+)
See skills/vision-ref.md

Subject not detected
See skills/vision-diag.md

Hand/body pose missing landmarks
See skills/vision-diag.md

Low confidence observations
See skills/vision-diag.md

UI freezing during processing
See skills/vision-diag.md

Coordinate conversion bugs
See skills/vision-diag.md

Text not recognized / wrong chars
See skills/vision-diag.md

Barcode not detected
See skills/vision-diag.md

DataScanner blank / no items
See skills/vision-diag.md

Document edges not detected
See skills/vision-diag.md

Decision Tree

digraph vision {
    start [label="Computer vision task" shape=ellipse];
    what [label="What do you need?" shape=diamond];

    start -> what;
    what -> "skills/vision-framework.md" [label="implement feature"];
    what -> "skills/vision-ref.md" [label="API reference"];
    what -> "skills/vision-ref.md" [label="Visual Intelligence"];
    what -> "skills/vision-diag.md" [label="something broken"];
}

Implementing (pose, segmentation, OCR, barcodes, documents, live scanning)? → skills/vision-framework.md

Visual Intelligence system integration (camera feature, iOS 26+)? → skills/vision-ref.md (Visual Intelligence section)

Need API reference / code examples? → skills/vision-ref.md

Debugging issues (detection failures, confidence, coordinates)? → skills/vision-diag.md

Critical Patterns

Implementation (skills/vision-framework.md):

Decision tree for choosing the right Vision API

Subject segmentation with VisionKit

Isolating objects while excluding hands (combining APIs)

Hand/body pose detection (21/18 landmarks)

Text recognition (fast vs accurate modes)

Barcode detection with symbology selection

Document scanning and structured extraction (iOS 26+)

Live scanning with DataScannerViewController

CoreImage HDR compositing

Diagnostics (skills/vision-diag.md):

Subject detection failures (edge of frame, lighting)

Landmark tracking issues (confidence thresholds)

Performance optimization (frame skipping, downscaling)

Coordinate conversion (lower-left vs top-left origin)

Text recognition failures (language, contrast)

Barcode detection issues (symbology, size, glare)

DataScanner troubleshooting (availability, data types)

Anti-Rationalization

Thought
Reality

"Vision framework is just a request/handler pattern"
Vision has coordinate conversion, confidence thresholds, and performance gotchas. vision-framework.md covers them.

"I'll handle text recognition without the skill"
VNRecognizeTextRequest has fast/accurate modes and language-specific settings. vision-framework.md has the patterns.

"Subject segmentation is straightforward"
Instance masks have HDR compositing and hand-exclusion patterns. vision-framework.md covers complex scenarios.

"Visual Intelligence is just the camera API"
Visual Intelligence is a system-level feature requiring IntentValueQuery and SemanticContentDescriptor. vision-ref.md has the integration section.

"I'll just process on the main thread"
Vision blocks UI on older devices. Users on iPhone 12 will experience frozen app. 15 min to add background queue.

Example Invocations

User: "How do I detect hand pose in an image?"
→ See skills/vision-framework.md

User: "Isolate a subject but exclude the user's hands"
→ See skills/vision-framework.md

User: "How do I read text from an image?"
→ See skills/vision-framework.md

User: "Scan QR codes with the camera"
→ See skills/vision-framework.md

User: "Subject detection isn't working"
→ See skills/vision-diag.md

User: "Text recognition returns wrong characters"
→ See skills/vision-diag.md

User: "Show me VNDetectHumanBodyPoseRequest examples"
→ See skills/vision-ref.md

User: "How do I make my app work with Visual Intelligence?"
→ See skills/vision-ref.md

User: "RecognizeDocumentsRequest API reference"
→ See skills/vision-ref.md