detections/_docs/02_tasks/AZ-141_test_tiling.md

Image Tiling Tests

Task: AZ-141_test_tiling Name: Image Tiling Tests Description: Implement E2E tests verifying GSD-based tiling for large images and tile boundary deduplication Complexity: 3 points Dependencies: AZ-138_test_infrastructure Component: Integration Tests Jira: AZ-141 Epic: AZ-137

Problem

Images exceeding 1.5x model dimensions (1280x1280) must be tiled based on Ground Sample Distance (GSD) calculations. Tests must verify that tiling produces correct results with coordinates normalized to the original image, and that duplicate detections at tile boundaries are properly merged.

Outcome

• Large image tiling confirmed with GSD-based tile sizing
• Detection coordinates normalized to original image dimensions (not tile-local)
• Tile boundary deduplication verified (no near-identical coordinate duplicates)
• Bounding box coordinates remain in 0.0-1.0 range

Scope

Included

• FT-P-04: Large image triggers GSD-based tiling
• FT-P-16: Tile deduplication removes duplicate detections at tile boundaries

Excluded

• Small image detection (covered in single image tests)
• Tiling performance benchmarks (covered in performance tests)
• Tile overlap configuration beyond default (implementation detail)

Acceptance Criteria

AC-1: GSD-based tiling Given an initialized engine and a large image (4000x3000) When POST /detect is called with altitude, focal_length, sensor_width config Then detections are returned with coordinates in 0.0-1.0 range relative to the full original image

AC-2: Tile boundary deduplication Given an initialized engine and a large image with tile overlap When POST /detect is called with tiling config including big_image_tile_overlap_percent Then no two detections of the same class have coordinates within 0.01 of each other (TILE_DUPLICATE_CONFIDENCE_THRESHOLD)

Non-Functional Requirements

Performance

• Large image processing within 60s (tiling adds overhead)

Integration Tests

AC Ref	Initial Data/Conditions	What to Test	Expected Behavior	NFR References
AC-1	Engine warm, large-image (4000x3000), GSD config	POST /detect with large image	Detections with coords 0.0-1.0 relative to full image	Max 60s
AC-2	Engine warm, large-image, tile overlap config	Check for near-duplicate detections	No same-class duplicates within 0.01 coords	Max 60s

Constraints

• Large image fixture must exceed 1.5x model input (1920x1920) to trigger tiling
• GSD parameters must be physically plausible for the test scenario
• Tile dedup threshold is hardcoded at 0.01 in the system

Risks & Mitigation

Risk 1: No detections at tile boundaries

• Risk: Test image may not have objects near tile boundaries
• Mitigation: Verify tiling occurred by checking processing time is greater than small image; dedup assertion is vacuously true if no boundary objects