comfyui_ds

ComfyUI Document Scanner

A custom ComfyUI node that implements advanced document scanning with automatic perspective correction and multiple enhancement options.

Features

• Automatic Document Detection: Uses contour detection to identify document boundaries
• Perspective Correction: Corrects skewed documents to flat, rectangular format
• Multiple Enhancement Methods: 6 different enhancement algorithms for optimal results
• Batch Processing: Handles multiple images at once
• Debug Visualization: Optional edge detection visualization
• Fallback Safety: Graceful handling of edge cases and errors

Nodes

Document Scanner

Full-featured node with all configuration options:

Inputs:

• image: Input document image(s)
• enhancement_method: Choose from 6 enhancement methods
  • sharpening: General purpose sharpening with HSV adjustments
  • cartooning: Cartoon-like effect with edge detection
  • clahe: Contrast Limited Adaptive Histogram Equalization
  • threshold: Binary thresholding with Otsu's method
  • adaptive_threshold: Local adaptive thresholding
  • flat_field: Flat field correction for uneven lighting
• edge_threshold_low/high: Canny edge detection thresholds (20, 70 default)
• blur_kernel_size: Bilateral filter kernel size (5 default)
• skip_preprocessing: Skip GrabCut text removal step
• return_debug_edges: Output edge detection visualization

Outputs:

• scanned_image: Final processed document
• debug_edges: Edge detection visualization (if enabled)

Simple Document Scanner

Simplified interface with preset configurations:

Inputs:

• image: Input document image(s)
• enhancement: Choose enhancement preset
  • auto: General purpose (sharpening)
  • text: Optimized for text documents (adaptive threshold)
  • photo: Optimized for photo documents (CLAHE)

Outputs:

• scanned_image: Final processed document

Algorithm Overview

1. Preprocessing: Optional GrabCut segmentation to remove text
2. Grayscale Conversion: Convert to single channel for processing
3. Blur: Bilateral filtering for edge-preserving noise reduction
4. Edge Detection: Canny edge detection to find document boundaries
5. Contour Detection: Find largest quadrilateral contour
6. Perspective Correction: Warp document to rectangular format
7. Enhancement: Apply selected enhancement method

Installation

1. Copy the comfyui_document_scanner folder to your ComfyUI custom_nodes directory
2. Install dependencies: pip install -r requirements.txt
3. Restart ComfyUI
4. The nodes will appear under image/processing category

Requirements

• opencv-python >= 4.5.0
• numpy >= 1.20.0
• torch >= 1.9.0 (provided by ComfyUI)

Error Handling

The node includes robust error handling:

• If document detection fails, returns original image
• If perspective correction fails, skips correction step
• Graceful fallbacks for all processing steps
• Error messages logged to console

Tips for Best Results

• Use well-lit images with clear document boundaries
• Ensure document occupies significant portion of image
• For text documents, try adaptive_threshold enhancement
• For photos/mixed content, try clahe or sharpening
• Adjust edge detection thresholds if having detection issues
• Use debug edges output to troubleshoot detection problems