Jason Hu
All projects
07 / Purdue XYZT Labs

From pixels to surface profiles.

I developed a 3D sensing pipeline that converted 2D camera measurements into repeatable metric surface profiles, combining optical geometry, calibration, and Python/OpenCV processing.

My role
Research Assistant
Timeline / status
2024
Research contribution completed
Disciplines
Python · OpenCV · Optical triangulation · Experimental design
01 / RAW CAMERA FRAME
Raw camera frameResearch media slot
Explanatory schematic · no experimental data shown

Camera pixels capture the illuminated surface.

02 / DISTORTION CORRECTION
Distortion correctionResearch media slot
Explanatory schematic · no experimental data shown

Correct lens distortion before geometric reconstruction.

03 / LASER STRIPE EXTRACTION
Laser stripe extractionResearch media slot
Explanatory schematic · no experimental data shown

Isolate the stripe for consistent image-space measurement.

04 / SUBPIXEL LOCALIZATION
Subpixel localizationResearch media slot
Explanatory schematic · no experimental data shown

Estimate the stripe center at finer than integer-pixel resolution.

05 / METRIC SURFACE PROFILE
Metric surface profileResearch media slot
SurfaceExplanatory schematic · no experimental data shown

Calibration and triangulation connect pixels to physical geometry.

End-to-end laser-triangulation pipeline converting camera measurements into calibrated metric surface profiles. Schematics reserve space for research imagery; they do not depict recorded measurements.

20+Benchmark trials
2D → 3DCamera measurements to metric profiles
SubpixelLaser-stripe localization
01 / Laser-triangulation research

The Problem

A camera measures pixels; inspection requires physical dimensions. I developed the calibrated relationship between camera measurements, laser geometry, and the physical surface needed to reconstruct repeatable metric profiles.

Laser triangulation geometryResearch media slot
Test surfaceCameraLaserCamera / laser baselineViewing rayLaser planeIntersection pointReconstructed XYZ location
Camera + laser
The baseline defines their relative position.
Viewing ray + laser plane
Their intersection locates the illuminated surface point.
Reconstructed XYZ
Calibration relates this location to physical geometry.
Explanatory schematic · no experimental data shown
Generic triangulation geometry: a camera viewing ray intersects the laser plane at the illuminated surface. This explanatory layout is not the lab’s measured sensor configuration.
02 / Laser-triangulation research

My Contribution

  • Developed a calibrated laser-triangulation 3D sensing pipeline for additive-manufacturing inspection and real-time object tracking.
  • Implemented and benchmarked distortion correction and subpixel laser-stripe extraction in Python/OpenCV.
  • Evaluated sensor geometry and experimental conditions affecting reconstruction quality.
  • Refined alignment and calibration through 20+ benchmark trials to improve measurement consistency.
03 / Laser-triangulation research

Sensing Architecture

Reconstruction depends on the physical relationship between the camera, laser plane, and test surface. I refined sensor geometry and alignment alongside calibration so image-space localization could be related consistently to physical surface location.

Experimental setup photographResearch media slot
CameraLaserCalibration targetTest surface

Experimental photograph slot
Component labels can accompany the final image.

Explanatory schematic · no experimental data shown
Experimental setup photograph slot for calibration, reconstruction, and repeated benchmark trials. Future imagery can identify the camera, laser, calibration target, and test surface.
Physical geometryCamera / laser relationship + alignmentImage-space measurementDistortion correction + stripe localization
04 / Laser-triangulation research

Image Processing Pipeline

I implemented and benchmarked distortion correction and subpixel stripe extraction in Python/OpenCV. Each processing step prepares a more consistent image-space measurement for reconstruction.

01 / RAW IMAGE
Raw camera frameResearch media slot
Explanatory schematic · no experimental data shown

Camera pixels capture the illuminated surface.

02 / DISTORTION CORRECTED
Distortion correctionResearch media slot
Explanatory schematic · no experimental data shown

Correct lens distortion before geometric reconstruction.

03 / LASER ISOLATED
Laser stripe extractionResearch media slot
Explanatory schematic · no experimental data shown

Isolate the stripe for consistent image-space measurement.

04 / SUBPIXEL CENTERLINE
Subpixel localizationResearch media slot
Explanatory schematic · no experimental data shown

Estimate the stripe center at finer than integer-pixel resolution.

Subpixel Stripe Localization

Choosing the brightest integer pixel limits localization to the pixel grid. Estimating the stripe center from its intensity distribution provides finer image-space resolution and supports measurement consistency.

Neighboring camera pixels
Stripe intensity is distributed across several pixels.
Pixel positionIntensity (schematic)
The intensity distribution informs center estimation.
Estimated stripe center
Localize between integer pixel positions.

Explanatory diagram only · curves and pixel intensities are illustrative, not trial data or a specified extraction algorithm.

05 / Laser-triangulation research

Calibration & Reconstruction

Calibration and optical geometry establish the transformation from image-space measurements to physical surface location. Distortion correction precedes triangulation so systematic image distortion does not propagate directly into the metric reconstruction.

Calibration / distortion correctionResearch media slot
Explanatory schematic · no experimental data shown
Calibration imagery slot: connect the camera model and distortion correction to reconstruction.
Metric surface profileResearch media slot
SurfaceExplanatory schematic · no experimental data shown
Research output slot: the calibrated pipeline produces metric surface profiles from camera measurements.
Image-space stripe centerCalibrated camera / laser geometryPhysical surface location
06 / Laser-triangulation research

Engineering Decisions

Decision 01

Subpixel localization instead of pixel-level detection

I worked on stripe-center estimation to obtain finer image-space localization than selecting an integer pixel, supporting consistent measurements across frames.

Decision 02

Correct distortion before metric reconstruction

I benchmarked distortion correction before reconstruction because lens distortion can introduce systematic spatial error into the camera-to-surface relationship.

Decision 03

Refine geometry and calibration experimentally

I refined camera/laser geometry, physical alignment, calibration, and extraction through repeated testing. Reconstruction depends on the sensing arrangement as well as the software pipeline.

07 / Laser-triangulation research

Experimental Development

01 / Research progression

Early trials

Early trial image / observationResearch media slot
Explanatory schematic · no experimental data shown
Observation
Reconstruction and alignment inconsistencies.
Engineering change
Identify geometry, calibration, and extraction factors affecting consistency.
Learning / evaluation
Establish what needs refinement before repeated benchmarking.
02 / Research progression

Geometry / calibration refinement

Geometry / calibration refinementResearch media slot
SurfaceExplanatory schematic · no experimental data shown
Observation
Reconstruction links physical alignment with image processing.
Engineering change
Adjust sensor geometry, alignment, calibration, and stripe extraction.
Learning / evaluation
Evaluate the sensing arrangement and processing as one system.
03 / Research progression

20+ benchmark trials

Benchmark trial outputResearch media slot
SurfaceExplanatory schematic · no experimental data shown
Observation
Repeated reconstruction and tracking behavior.
Engineering change
Benchmark the refined pipeline under repeated experimental conditions.
Learning / evaluation
Evaluate reconstruction error, repeatability, tracking stability, and consistency.
08 / Laser-triangulation research

Validation

20+ trials to evaluate reconstruction error, repeatability, tracking stability, and measurement consistency.

Validation data / error plotResearch media slot
Reconstruction errorRepeatabilityTracking stabilityMeasurement consistency

Validation data / error plot
Experimental dataset not supplied · no values plotted

Explanatory schematic · no experimental data shown
Validation data / error plot slot. Quantitative trial results are not supplied, so no numerical accuracy, repeatability, or error reduction is reported here.
09 / Laser-triangulation research

From image data to metric geometry

Reconstructed surface / metric profileResearch media slot
SurfaceExplanatory schematic · no experimental data shown
Reconstructed surface/profile output slot for the strongest research visualization. The schematic illustrates the output type rather than an experimental result.
2D camera dataCalibrated geometryMetric surface profile

I developed a calibrated pipeline converting 2D camera measurements into repeatable metric surface profiles. The work combined optical geometry, Python/OpenCV processing, and repeated experimental refinement to support additive-manufacturing inspection and real-time object tracking.

NEXT CASE STUDY / 08

Payloads, ready for flight.

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