Document Processing Guide — EG-Docs Editor

Importing Document Scans

When you import images, the categorization dialog lets you tag each file as a Photo or Document. Tagged documents open in the Document tab, which auto-processes them on a worker thread:

Noise reduction
White-balance correction
Contrast S-curve enhancement
Sharpening
Auto edge detection

This gives you a clean starting point for every document.

Auto Edge Detection & Crop

The document tab automatically detects document edges using a ranked quad scoring system that evaluates:

Coverage — How well the quad covers the image area
90° Corners — How close to right angles the corners are
Symmetry — Overall quad symmetry
Convexity — Shape convexity score

Open a document scan

Import a scanned document. The app auto-detects edges and seeds them into the perspective crop tool (visible as 4 draggable corner handles).

Adjust detection sensitivity

Use the Sensitivity slider (1–100) if the auto-detection missed the edges. Higher values detect smaller/fainter documents; lower values focus on dominant rectangles.

Click-to-Detect

If auto-detection doesn’t find the right edges, click anywhere on the document in the preview. The app uses flood-fill + Otsu/adaptive contour search around your click point.

Apply perspective correction

Drag the 4 corner handles to align with the document corners. Click Apply to straighten the document to a perfect rectangle.

Manual Crop Tool

For documents where edge detection isn’t needed, use the Manual Crop tool (press C). It supports optional aspect ratio lock and a rotation handle for skewed scans.

Auto-Enhance (Scan Look)

The Auto-Enhance feature applies a professional-grade scan enhancement pipeline:

Flat-field division — Removes uneven lighting and shadows from the background
Paper becomes white — Background is normalized to pure white
Text becomes dark — Foreground content is darkened for maximum contrast
Sharpening — Final sharpening pass for crisp text

Click the Auto-Enhance button in the toolbar to apply it.

Effect Presets

Six presets for different document types:

Crisp Color — Vibrant, high-contrast color documents
Soft / Photocopy — Classic photocopier look
Vivid ID / Card — Optimized for identity cards and plastic cards
Lighten Faded — Restores faded thermal paper or old documents
Grayscale — Pure grayscale for black-and-white output
High-Contrast B&W — Maximum contrast binary output

Adjustments

Fine-tune with individual sliders: Brightness, Contrast, Sharpness, and a Black & White blend slider. Unlike the Photo tab, document adjustments are non-destructive per-document.

Two-Sided Pages

For scanning booklets or double-sided documents:

Load the back-side image

Click Load Back and select the scan of the reverse side.

Enable Two-Sided

Check the Two-Sided checkbox. The front and back are paired on one page for printing.

Size Templates for Documents

Nine size templates cover common document formats:

Fit to Page, PAN / Other IDs (85.6×54mm), Vertical ID (54×85.6mm)
Long Aadhaar (90×222mm), Passbook (210×190mm / 210×95mm)
Admit / Registration Card (210×148mm), Old Birth Certificate (180×215mm)
A4, A5, A6, Letter, plus Custom sizes with mm/cm/in/px units

Multi-Document Manager (Documents Section)

The Documents section (separate from the single-document editor) handles batch workflows:

Thumbnail list — Vertical list of documents with quick-action buttons (Auto Crop, Detect, Crop tool, Auto-Enhance, B&W, Rotate, Reset).
Auto-Process All — Run enhance + edge detect + perspective correct on every document in one click (threaded).
Document position — 9 placement options on the page (Center, Top, Bottom, Left, Right, corners).
Two-on-one-page — Pairs consecutive documents (1+2, 3+4, etc.) to save paper.
Make PDF (All) — Combine all documents into a single multi-page PDF with one click.

Exporting Documents

Use the Export dialog (Ctrl+S) to:

Save individual documents as images (PNG, JPEG)
Generate multi-page PDFs via ReportLab
Choose resolution (25%/50%/75%/100%) and JPEG quality
Set a target file size for online uploads

The PDF size estimator shows live KB/MB values as you adjust settings.

Size Reducer

Need to fit a document under a strict file size limit (e.g., 100 KB for a government form)? The Size Reducer tool (Ctrl+Shift+C) uses a smart binary-search strategy:

First reduces JPEG quality
Then progressively downscales if needed (preserving aspect ratio)
Built-in templates for PAN, Passport, Aadhaar, Admission Forms, Job Applications & more