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Optical profiler CSI

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INTERFEROMETRIC MICROSCOPE
Drag to orbit · scroll to zoom the 3D view
10× NA 0.25
Head engagedλ 550 nm / Coherence scanning interferometry
Surface height128 × 128
▱Your surface starts hereAcquire a scan to reconstruct height.
−
−µm
Select a pixel to inspect its signal
Pixel signal Intensity
Inspect the interference packet
behind every measured height.
Raw intensity + reconstructed envelope

Camera full scale: 4095 ADU · dashed envelope is a modulation guide, not a second camera reading.

01
GUIDED PRACTICE
Make your first surface measurement

The reference sample is mounted. Acquire a scan, then inspect a pixel on each terrace.

MVLscope / Optical ProfilometryEducational scalar model · CSI prototype
ABOUT THIS LABORATORY

From interference to surface height.

Move through focus, record the interference signal, and find the centre of its modulation envelope. Each accepted packet gives a height estimate. Passing signal checks does not establish accuracy.

A practical starting point

Use the mounted reference terraces, 10× objective, −3 to +3 µm scan and 2 ms exposure. Acquire, select pixels on both plateaus, then inspect the measured step. Try a narrower scan or higher exposure to see why measurements fail.

What is modeled

Scalar CSI signals, seeded camera noise (Gaussian approximation to shot noise at high counts), clipping, envelope localization, stage position, calibration scale errors, invalid masks, region analysis and a common-tilt step fit. Results come from acquired signals; changing the view does not change a measurement.

Quality and calibration

Valid surface counts pixels that pass the signal checks. The checks reject weak or poorly fitted packets; passing them does not prove accuracy. Their thresholds are empirical safeguards for this Gaussian-envelope teaching model, not universal CSI limits. Calibration requires three comparable reference scans, adequate terrace coverage and low variation. An applied correction remains in effect until you reset it. Removing an injected scale error changes the virtual instrument: reset the Z scale and acquire again. Earlier scans retain their recorded correction.

“Raw heights” means unlevelled reconstructed heights. The export does not retain a complete raw camera-frame stack.

Model limits

This browser prototype uses a 128 × 128 sensor crop, one surface element per pixel and a Gaussian coherence envelope. Diffraction, multiple scattering, material phase changes, films, high-NA effects and edge artifacts are not quantitatively modeled. The 3D instrument is schematic. This is training data, not certified metrology.

PSI, confocal profiling and focus variation remain later milestones. The lab and learning checkpoints save in this browser when storage is available. Export a measurement for a portable copy.

Read the NPL CSI good-practice guide ↗
MEASUREMENT BUNDLE

Your measurement is ready.

Save the height arrays, validity masks, settings, processing history, selected signal and a labeled preview together.

↓ Download ZIP

All results are labeled simulated. The archive is prepared on your device.

Reset the optical profiler?

This clears the current measurement, scan history and setup. Export any measurement you want to keep first. Learning progress is retained.