lotosbin Red Pen Mark Remover
Removes red handwritten marks from scanned documents and images using color detection and inpainting algorithms.
Installation
pip install opencv-python pillow numpy
Usage
Python API
from red_pen_remover import remove_red_marks, batch_remove_red_marks, preview_masks
# Single image
remove_red_marks("document.jpg", "clean_document.jpg")
# Adjust sensitivity (0.0-1.0, lower = more aggressive)
remove_red_marks("document.jpg", "clean.jpg", sensitivity=0.2)
# Batch processing
batch_remove_red_marks("input_folder/", "output_folder/")
# Preview mask detection
preview_masks("document.jpg", "preview.jpg")
Command Line
python red_pen_remover.py input.jpg output.jpg [sensitivity]
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
| input_path | str | - | Path to input image |
| output_path | str | - | Path to save output |
| sensitivity | float | 0.3 | Color detection sensitivity (0.0-1.0) |
| radius | int | 3 | Inpainting radius |
| method | str | "telea" | Inpainting method: "telea" or "ns" |
Tips
- High sensitivity (0.4-0.5): Better for bright, clear scans
- Low sensitivity (0.1-0.2): Better for dark or noisy images
- Use
preview_masks()to tune sensitivity before processing - Works best on documents with clear contrast between text and marks
How It Works
- Color Detection: Converts image to HSV color space and identifies red pixels
- Mask Processing: Applies morphological operations to clean up the mask
- Inpainting: Uses OpenCV's inpainting algorithm to fill in removed regions