Preprocess figures for digitization
Import a figure, crop the ROI, correct rotation/perspective, optionally calibrate axes, and export a rectified PNG + JSON mapping.
Input Data Source: —
Original size
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Working stage
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Zoom
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Cursor
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Workspace Mode
Pan: drag background • Zoom: mouse wheel • Precision: arrow keys (Shift = 10px). In Warp mode, drag
corners labeled TL/TR/BR/BL. In Calibrate mode, click points on the rectified image.
Crop (ROI)
ROI (orig px)
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Deskew (Rotate)
Rotation is applied after crop and before perspective warp.
Perspective Warp
Pre-warp size
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Rectified size
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Drag TL/TR/BR/BL points. Use arrow keys to nudge the active point (Shift = 10px). Hover shows pixel and
(if calibrated) data coords.
Axis Calibration (Optional)
X points
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Y points
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Calibration is applied on the rectified image. Switch to Warp mode and Apply Warp first.
Then switch to Calibrate and click points.
Export
Exports are designed to feed the downstream digitizer tool, but are useful standalone.
Critical Engineering Disclaimer
This tool performs manual geometric correction and optional axis calibration. Results depend strongly on accurate corner placement and calibration points. Always validate against known reference values. Runs entirely in your browser (no server processing or storage).
Mode: Crop
Stage: —
Working: —
Tip: Hold Shift for 10px nudges
Rectified Preview
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Loupe