ImageWand

A powerful command-line tool for image manipulation, including PDF to image conversion, image resizing, auto-fixing scanned images, applying filters, and merging scanned images.

Installation

pip install imagewand

Commands Overview

ImageWand provides several commands for different image manipulation tasks:

• pdf2img: Convert PDF files to images
• resize: Resize images
• align: Automatically align tilted images to be horizontal/vertical
• filter: Apply various filters to images
• merge: Merge multiple scanned images into one
• autocrop: Automatically crop images using frame detection or border removal
• info: Display detailed information about images

Command Usage

PDF to Images

Convert PDF files to images with customizable DPI and format:

# Basic usage
imagewand pdf2img input.pdf

# Specify output directory and format
imagewand pdf2img input.pdf -o output_dir -f png

# Set custom DPI
imagewand pdf2img input.pdf -d 300

Resize Images

Resize images while maintaining aspect ratio:

# Resize by width
imagewand resize input.jpg -w 800

# Resize by height
imagewand resize input.jpg --height 600

# Resize by percentage
imagewand resize input.jpg -p 50

# Specify output path
imagewand resize input.jpg -o resized.jpg -w 800

Align Tilted Images

Automatically detect and correct the rotation of tilted images:

# Basic usage - auto-detects the best method
imagewand align tilted_scan.jpg

# Specify output path
imagewand align tilted_scan.jpg -o aligned.jpg

# Choose specific alignment method
imagewand align tilted_scan.jpg -m hough
imagewand align tilted_scan.jpg -m contour
imagewand align tilted_scan.jpg -m center

# Adjust minimum angle threshold for correction (default: 1.0 degrees)
imagewand align tilted_scan.jpg -a 0.5  # More sensitive
imagewand align tilted_scan.jpg -a 2.0  # Less sensitive

Alignment methods explained:

• auto (default): Tries all methods and uses the one that detects the most significant angle
• hough: Uses Hough Line Transform, best for documents with clear straight lines
• contour: Uses contour analysis, better for images with distinct shapes
• center: Focuses on the central portion of the image, ignoring the background (best for photos with clear subjects)

Output filenames:

• Default: image_aligned.jpg (for default parameters)
• With parameters: image_aligned_hough_a0.5.jpg (for method=hough, angle_threshold=0.5)

Apply Filters

Apply various image filters:

# Apply single filter
imagewand filter input.jpg -f grayscale

# Apply multiple filters
imagewand filter input.jpg -f "grayscale,sharpen"

# Process directory recursively
imagewand filter images/ -f grayscale -r

# List available filters
imagewand list-filters

Filter Parameters

You can customize filter parameters using the format filtername:param=value:

# Adjust contrast level (default is 1.5)
imagewand filter drawing.jpg -f "contrast:factor=1.2"

# Multiple filters with custom parameters
imagewand filter drawing.jpg -f "saturation:factor=1.3,contrast:factor=1.2,sharpen:factor=1.8"

# Mix of default and custom parameters
imagewand filter drawing.jpg -f "saturation:factor=1.3,contrast,sharpen:factor=2.0"

Common filter parameters:

• contrast:factor=1.2 - Lighter contrast (default: 1.5)
• sharpen:factor=1.8 - Stronger sharpening (default: 2.0)
• blur:radius=3 - Adjust blur radius (default: 2)

Merge Images

Merge multiple scanned images into one:

# Merge all images in a directory
imagewand merge images_folder/ -o merged.jpg

# Merge specific images
imagewand merge image1.jpg image2.jpg image3.jpg -o merged.jpg

# Enable debug mode to see the matching process
imagewand merge images_folder/ -o merged.jpg --debug

Autocrop Images

Automatically crop images using frame detection or border removal:

# Auto mode - Tries frame detection first, falls back to border removal
imagewand autocrop photo.jpg

# Frame mode - Extract photo from contrasting frame/background
imagewand autocrop photo.jpg -m frame
imagewand autocrop photo.jpg -m frame --margin -5  # More aggressive crop
imagewand autocrop photo.jpg -m frame --margin 10  # Add margin

# Border mode - Remove white margins only
imagewand autocrop photo.jpg -m border
imagewand autocrop photo.jpg -m border -b -5  # More aggressive crop
imagewand autocrop photo.jpg -m border -b 10  # Keep more border

Cropping modes explained:

• auto (default): Tries frame detection first, falls back to border removal if no frame is detected

• frame: Best for photos on contrasting backgrounds (e.g., artwork on black paper)

  • Use --margin to adjust cropping (negative for tighter crop, positive for more margin)
  • Default margin is -5 for slightly aggressive crop

• border: Best for documents with white margins

  • Use -b to adjust border percentage (negative for tighter crop, positive to keep more border)
  • Default border is 0 for exact content boundaries

Output filenames:

• Auto mode: photo_auto.jpg, photo_auto_frame.jpg, or photo_auto_border.jpg
• Frame mode: photo_frame.jpg or photo_frame_m10.jpg (with margin 10)
• Border mode: photo_border.jpg or photo_border_b10.jpg (with 10% border)

Image Information

Display comprehensive information about images:

# Basic usage
imagewand info photo.jpg

The info command displays:

• Basic file information: filename, path, size, modification date
• Image properties: dimensions, format, color mode, color depth
• DPI information
• Color statistics: brightness, RGB channel values, sharpness
• EXIF data (when --verbose flag is used)