Offline 3D change review
Field evidence, kept accountable.
Capture the same nearby surface at different times, align the observations, inspect geometric change, and preserve a professional decision trail—all on a supported LiDAR-equipped iPhone.
The whole idea
Make change visible without hiding how the result was made.
StrataDelta is built for repeat, near-field observation. A team records a baseline of a surface, returns later to record a repeat, and compares the two in a shared local coordinate frame.
The app then helps a reviewer inspect where measured geometry differs. Raw capture, derived analysis, and professional judgment remain separate, so a new calculation or decision does not rewrite the original field evidence.
How it works
Six steps from site context to reviewable evidence.
Each stage records its inputs and limitations. Automatic outputs remain suggestions until the appropriate reviewer makes a decision.
Define the project
Record the responsible owner, site and asset, coordinate-reference context, control method, units, and the site-approved stand-off instruction.
Capture a baseline
From an authorized position, move the supported LiDAR iPhone slowly across the nearby surface. StrataDelta records depth, imagery, pose, tracking, interruptions, and device context locally.
Review source quality
Inspect depth coverage, confidence, tracking, motion, and interruptions. A qualified reviewer records whether the observation is acceptable, usable with limitations, or rejected.
Capture the repeat
Return to the same area and follow the approved procedure again, keeping useful coverage and viewpoint overlap with the baseline.
Align and calculate change
Register the repeat observation to the baseline, inspect residuals and overlap, choose an explicit cell resolution in metres, then calculate signed geometric change along the selected axis.
Review, document, and export
Inspect point clouds, change grids, cross-sections, bounded areas, and volume summaries. Record findings and export a controlled evidence package only when needed.
What you can inspect
Evidence beside every result.
Capture quality
Depth availability and confidence, tracking state, camera path, interruptions, coverage, motion, thermal state, and storage context.
Registration quality
Alignment recipe, transform, source hashes, residual statistics, overlap, and the reviewer’s registration decision.
Geometric change
Signed change maps, selectable cross-sections, coverage and no-data areas, summary statistics, and bounded positive or negative volume integration.
Audit trail
Immutable observation records, processing recipes, finding revisions, named decisions, timestamps, and provenance-backed exports.
Quality review
A flag asks for judgment. It does not invent accuracy.
“Quality review required” means one or more observations crossed a review threshold in the active processing recipe—for example, missing depth frames, non-normal tracking, or too many low-confidence depth samples.
The reviewer is the qualified survey, geotechnical, engineering, or inspection professional designated by the organization’s approved procedure. It is not Apple, and it is not an automatic StrataDelta approval.
Resolution
Cell size controls detail, not truth.
Comparison resolution is the spatial cell size used to summarize change, entered in metres. Smaller cells may show finer variation, but they do not create missing measurements or make the device more accurate.
Choose resolution from capture density, coverage, alignment residuals, site geometry, and an independently validated procedure. The app intentionally does not prescribe a universal value.
Designed for accountable field work
Useful offline, explicit at every handoff.
- Supported hardware: an iPhone that reports ARKit world tracking and LiDAR scene-depth capability.
- Local operation: projects and processing remain on the device; no account or network connection is required.
- User-controlled export: JSON, PDF, CSV, PLY, and PNG evidence leaves the app only through an explicit iOS share action.
- Reproducible records: inputs, recipes, units, hashes, quality signals, decisions, limitations, and uncertainty context travel with the result.
Privacy by architecture
Processing stays on the iPhone.
The app has no account system, advertising, third-party analytics SDK, or automatic cloud upload. Evidence leaves the device only when a user explicitly exports it through the iOS share sheet.
Professional-use boundary. StrataDelta supports professional review. It is not a slope-failure warning system, a certified survey instrument, or authorization to enter a hazardous area. Accuracy and field uncertainty must be independently validated for the intended use.