blur

Apply Gaussian blur effect to images with adjustable intensity.

Usage

Description

The blur command applies a Gaussian blur effect to images using a configurable sigma parameter. Gaussian blur creates a smooth, natural-looking blur by applying a weighted average based on a bell curve distribution. Perfect for background effects, privacy protection, or artistic softening.

Options

Sigma Parameter

The sigma value controls blur intensity:

Examples

Basic Blur

Custom Output

# Save with custom name
mediaproc image blur photo.jpg -o blurred-photo.jpg

# Specify quality
mediaproc image blur image.png -s 20 -q 95 -o result.png

# Different directory
mediaproc image blur pic.jpg -s 10 -o ./blurred/pic.jpg

Batch Processing

# Blur multiple images
mediaproc image blur "photos/*.jpg" -s 15

# With verbose output
mediaproc image blur "backgrounds/*.png" -s 25 -v

# Preview first
mediaproc image blur "images/*.jpg" -s 30 --dry-run

Portrait Background Blur

# Subtle background blur (bokeh effect)
mediaproc image blur portrait-bg.jpg -s 5 -o bokeh.jpg

# Medium depth of field simulation
mediaproc image blur photo-bg.jpg -s 10 -o dof.jpg

# Strong background blur
mediaproc image blur subject.jpg -s 20 -o focused.jpg

Privacy Protection

# Obscure faces in photo
mediaproc image blur faces.jpg -s 40 -o anonymous.jpg

# Blur license plates
mediaproc image blur car-photo.jpg -s 35 -o censored.jpg

# Hide sensitive information
mediaproc image blur document.png -s 50 -o redacted.png

Artistic Effects

# Dreamy soft focus
mediaproc image blur landscape.jpg -s 8 -o dreamy.jpg

# Abstract blur art
mediaproc image blur colorful.png -s 60 -o abstract.png

# Vintage soft look
mediaproc image blur portrait.jpg -s 4 -q 85 -o vintage.jpg

Background Preparation

# Blur background for text overlay
mediaproc image blur hero-bg.jpg -s 20 -o ready-for-text.jpg

# Soften background for UI
mediaproc image blur app-bg.png -s 15 -o soft-bg.png

Blur Strength Guide

Light Blur (1-5)

Use for:

• Portrait skin smoothing
• Subtle depth of field
• Minor background separation
• Soft focus effects

Example:

mediaproc image blur portrait.jpg -s 3

Medium Blur (5-15)

Use for:

• General background blur
• Product photo backgrounds
• Bokeh simulation
• Website hero images

Example:

mediaproc image blur background.jpg -s 10

Strong Blur (15-30)

Use for:

• Clear subject/background separation
• Emphasizing focus areas
• Creating depth
• Dramatic bokeh

Example:

mediaproc image blur scene.jpg -s 25

Heavy Blur (30+)

Use for:

• Privacy protection
• Anonymization
• Censoring information
• Abstract artistic effects

Example:

mediaproc image blur sensitive.jpg -s 40

Common Use Cases

Portrait Photography:

# Blur background to emphasize subject
mediaproc image blur portrait-background.jpg -s 12 -o bokeh.jpg

Privacy Protection:

# Obscure identifiable features
mediaproc image blur crowd-photo.jpg -s 35 -o anonymous.jpg

Web Design:

# Create soft background for hero section
mediaproc image blur hero-bg.jpg -s 18 -o web-bg.jpg

Product Photography:

# Blur background to highlight product
mediaproc image blur product-scene.jpg -s 8 -o clean-bg.jpg

Document Redaction:

# Hide sensitive information
mediaproc image blur confidential.png -s 45 -o redacted.png

Performance Tips

• Lower sigma values (1-10) are faster to process
• Higher sigma values (50+) take more time
• Blur is relatively fast compared to other operations
• Processing time increases with both image size and sigma value

Best Practices

1. Start Small: Test with low sigma and increase gradually
2. Preview First: Use --dry-run for batch operations
3. Quality Matters: Use -q 95+ for final outputs
4. Consider Purpose: Match sigma to use case (privacy vs aesthetics)
5. Batch Consistently: Use same sigma for related images

Technical Details

Gaussian Blur Algorithm

The blur uses a Gaussian function for weight distribution:

• Creates smooth, natural-looking blur
• Weights decrease with distance from center
• No harsh edges or artifacts
• Industry-standard algorithm

Edge Handling

Edges are handled by:

• Extending edge pixels outward
• Prevents dark borders
• Maintains image dimensions

Limitations

• Cannot unblur an already blurred image
• Very high sigma (greater than 100) may cause artifacts
• Extreme blur may reduce file size (less detail)
• Blur cannot be undone after saving

Comparison with Other Effects

Future Enhancements

These features are planned but not yet implemented:

• Motion blur: Directional blur simulation (FUTURE)
• Radial blur: Center-focused blur effect (FUTURE)
• Smart blur: Edge-preserving blur (FUTURE)
• Variable blur: Different strength across image (FUTURE)
• Mask support: Blur only specific regions (FUTURE)

Troubleshooting

Blur not strong enough:

• Increase sigma value (try 20-30)
• Ensure command completed successfully
• Check output file was created

Blur too strong:

• Decrease sigma value (try 3-8)
• Cannot undo blur after saving

Processing very slow:

• Expected with high sigma (50+)
• Reduce sigma for faster processing
• Consider image size reduction first

Quality loss:

• Increase quality setting: -q 95
• Use PNG for lossless (but larger files)
• Blur itself doesn't degrade quality (just softens)

Unexpected results:

• Verify sigma is in valid range (0.3-1000)
• Check input file isn't already heavily processed
• Try with verbose mode: -v

See Also

• median - Edge-preserving blur for noise reduction
• sharpen - Opposite effect (enhance details)
• pixelate - Alternative privacy protection
• gaussian-blur - Alias for blur (same command)