Auto Scan Deskew
Detect and auto-correct page rotations and alignments on mobile-photo or scanned PDF sheets instantly.
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Utilizes Hough transform edge fitting to probe grid axis and losslessly deskew pages to perfect horizontal alignment.
Designed for Trust and Speed
PDFRunway handles your documents locally, keeping data secure and processing lightning-fast.
Easy to Use
Simple 3-step processes designed for speed, clarity, and non-technical users.
Fast & Reliable
High-performance local compilation keeps processing fast, secure, and responsive.
100% Secure
Your documents never leave your browser. Zero uploads, 100% client-side privacy.
Works Anywhere
Access the full suite on any browser, system, desktop, or mobile device.
How to Use
Follow these three simple steps to process your file in seconds.
Provide skew PDF
Upload any PDF sheet carrying rotated or poorly aligned scanned documents.
Analyze and tweak
The engine auto-detects skew angle and draws aligning grids. Tweak angle manually if needed.
Straighten & download
Click execute to swing pages through a smooth gyroscope transition and download aligned PDF.
About This Tool
The PDF Scan Aligner is a mandatory utility for sanitizing tilted digital assets and mobile snapshots.
Documents scanned via physical flatbeds or captured quickly with smartphones often carry subtle rotations. Tilted pages look highly unprofessional, hinder text readability, and cause margins to clip during printing.
This tool utilizes robust Radon Transform and Hough Line detection algorithms to scan gradients and text lines under 20ms. It precisely measures skew down to 0.01 degrees and performs pixel-level Canvas rotation, snapping your receipts, contracts, and booklets back into crisp geometric alignment.
Use Cases
Receipt & Contract Archiving
Straighten quick hand-held mobile contract scans before saving them as formal digital PDF archives.
Academic Book Digitizing
Sanitize microfilm book scans where text lines drift out of horizontal margins.
Student Homework Grading
Correct homework snapshots taken by student phones, relaxing the eyes of grading teachers.
Frequently Asked Questions
Have questions? Find quick answers about this tool here.
We run high-speed Hough Line projections on text lines. Since formal prints have clear horizontal spacing patterns, finding the angle with the maximum variance isolates the rotation.
No. The engine calculates the rotated boundary and extends the Canvas using auto-padding, ensuring all margin text remains intact without cropping.
Yes, as long as there is an underlying structure of lines or general paragraphs, our algorithms can accurately lock onto the principal reading angle.