Sharpen

Sharpen images to enhance details and edges. Perfect for improving slightly blurry photos or enhancing image clarity.

Installation

Usage

Basic Usage

Options

Sharpening Parameters

Sigma (Strength)

Controls overall sharpening intensity:

0.3-0.7: Subtle enhancement

• Gentle sharpening
• Natural appearance
• Good for already sharp images

1.0-1.5: Normal sharpening (Recommended)

• Standard enhancement
• Balanced results
• Default: 1.0

2.0-3.0: Strong sharpening

• Heavy enhancement
• Noticeable effect
• Risk of halos if overdone

3.0+: Extreme sharpening

• Very strong effect
• High risk of artifacts
• Use with caution

Flat

Sharpening applied to smooth, flat areas:

• Lower values (0.5-1): Less sharpening in flat areas
• Default: 1
• Higher values (1.5-2): More sharpening in flat areas

Jagged

Sharpening applied to edges and jagged areas:

• Lower values (1-1.5): Gentler edge enhancement
• Default: 2
• Higher values (2.5-3): Stronger edge enhancement

Sharpening Guide

Subtle Sharpening

Gentle enhancement:

# Sigma: 0.3-0.7
mediaproc image sharpen photo.jpg -s 0.5

Use for: Already good images, portraits, natural photos.

Normal Sharpening

Standard enhancement:

# Sigma: 1.0-1.5
mediaproc image sharpen image.jpg -s 1.2

Use for: General photography, web images, prints.

Strong Sharpening

Heavy enhancement:

# Sigma: 2.0-3.0
mediaproc image sharpen photo.jpg -s 2.5

Use for: Very soft images, landscapes, architecture.

Custom Sharpening

Fine-tuned control:

# Custom flat and jagged
mediaproc image sharpen image.jpg -s 1.5 --flat 1 --jagged 2.5

Use for: Specific requirements, experimentation.

Examples

1. Default Sharpening

Apply standard sharpening:

mediaproc image sharpen photo.jpg

Result: Sigma 1, balanced enhancement.

2. Strong Sharpening

Heavy enhancement for soft images:

mediaproc image sharpen soft-image.jpg -s 2

Use: Very blurry or soft images.

3. Subtle Enhancement

Gentle sharpening:

mediaproc image sharpen good-photo.jpg -s 0.5

Use: Already sharp images, subtle boost.

4. Portrait Sharpening

Careful portrait enhancement:

mediaproc image sharpen portrait.jpg -s 0.7 --flat 0.5 --jagged 1.5

Portraits: Enhance details without harsh edges.

5. Landscape Sharpening

Strong landscape enhancement:

mediaproc image sharpen landscape.jpg -s 1.8 --jagged 2.5

Landscapes: Enhance details and edges.

6. Architecture Photography

Sharpen building details:

mediaproc image sharpen building.jpg -s 2 --jagged 3

Architecture: Crisp edges and details.

7. Batch Sharpening

Sharpen multiple images:

mediaproc image sharpen "photos/*.jpg" -s 1.2

Batch: Consistent enhancement.

8. High Quality Output

Maximum quality sharpening:

mediaproc image sharpen photo.jpg -s 1.5 -q 100

Print: No quality loss.

9. Comparison Tests

Test different strengths:

# Subtle
mediaproc image sharpen photo.jpg -s 0.5 -o subtle.jpg

# Normal
mediaproc image sharpen photo.jpg -s 1 -o normal.jpg

# Strong
mediaproc image sharpen photo.jpg -s 2 -o strong.jpg

Testing: Find optimal strength.

10. Web Image Sharpening

Enhance for web display:

mediaproc image sharpen web-image.jpg -s 1.2 -q 85

Web: Good sharpness, reasonable file size.

11. Product Photography

Sharpen product details:

mediaproc image sharpen product.jpg -s 1.5 --jagged 2.5 -q 95

E-commerce: Clear product details.

12. Scanned Documents

Enhance scanned text:

mediaproc image sharpen scan.jpg -s 2.5 --jagged 3

Documents: Crisp text and lines.

13. Macro Photography

Enhance fine details:

mediaproc image sharpen macro.jpg -s 1.8 --flat 1.5 --jagged 2.5

Macro: Intricate detail enhancement.

14. Verbose Output

Show processing info:

mediaproc image sharpen photo.jpg -s 1.5 --verbose

Info: Processing details, dimensions.

15. Preview Before Sharpening

Check settings:

mediaproc image sharpen image.jpg -s 2 --dry-run

Safety: Verify before processing.

Use Cases

1. Correct Slightly Blurry Photos

Fix minor blur issues:

# Camera shake
mediaproc image sharpen blurry.jpg -s 1.5

# Focus issues
mediaproc image sharpen soft-focus.jpg -s 1.8

Photography: Salvage soft photos.

2. Enhance After Resizing

Sharpen after downsizing:

# Resize
mediaproc image resize large.jpg -w 1200 -o resized.jpg

# Sharpen
mediaproc image sharpen resized.jpg -s 1.2

Workflow: Restore sharpness after resize.

3. Web Image Preparation

Prepare sharp web images:

# Optimize and sharpen
mediaproc image sharpen photo.jpg -s 1.2 -q 85 -o web.jpg

Web: Clear, optimized images.

4. Print Preparation

Enhance for print output:

# Print sharpening
mediaproc image sharpen photo.jpg -s 1.5 -q 95

Print: Professional print quality.

5. Product Photography

E-commerce product enhancement:

# Sharpen details
mediaproc image sharpen "products/*.jpg" -s 1.5 --jagged 2.5

E-commerce: Clear product images.

6. Document Scanning

Enhance scanned documents:

# Sharpen text and diagrams
mediaproc image sharpen scan.jpg -s 2.5

Documents: Readable scans.

7. Social Media

Prepare eye-catching posts:

# Social media sharpening
mediaproc image sharpen post.jpg -s 1.3 -q 90

Social: Crisp social media images.

8. Portrait Enhancement

Careful portrait sharpening:

# Enhance eyes and details
mediaproc image sharpen portrait.jpg -s 0.8 --flat 0.5

Portraits: Natural enhancement.

9. Landscape Photography

Dramatic landscape enhancement:

# Strong landscape sharpening
mediaproc image sharpen landscape.jpg -s 1.8 --jagged 2.5

Landscapes: Enhanced details and textures.

10. Macro Photography

Enhance fine details:

# Macro detail enhancement
mediaproc image sharpen macro.jpg -s 1.7 --jagged 2.8

Macro: Intricate detail clarity.

Combining with Other Commands

Resize + Sharpen

Standard workflow:

# Resize
mediaproc image resize large.jpg -w 1920 -o resized.jpg

# Sharpen to recover detail
mediaproc image sharpen resized.jpg -s 1.2

Best Practice: Always sharpen after resizing.

Auto-Enhance + Sharpen

Complete enhancement:

# Auto enhance
mediaproc image auto-enhance photo.jpg -o enhanced.jpg

# Sharpen
mediaproc image sharpen enhanced.jpg -s 1

Workflow: Comprehensive improvement.

Blur + Sharpen

Selective focus simulation:

# Blur background
mediaproc image blur background.jpg -s 5 -o blurred.jpg

# Sharpen subject (requires masking)
# Manual workflow needed

Advanced: Bokeh simulation.

Sharpen + Optimize

Prepare for web:

# Sharpen
mediaproc image sharpen photo.jpg -s 1.2 -o sharp.jpg

# Optimize file size
mediaproc image optimize sharp.jpg -q 85

Web Workflow: Sharp, optimized images.

Technical Details

Sharpening Algorithm

Uses unsharp mask technique:

1. Gaussian blur: Creates blurred version
2. Subtract: Finds difference (edges)
3. Add back: Enhances edges in original

Sigma Parameter

Controls Gaussian blur radius:

• Larger sigma = stronger sharpening
• Too large = halos and artifacts
• Optimal: 0.5-2 for most images

Flat vs Jagged

Flat (m1): Controls sharpening in uniform areas Jagged (m2): Controls sharpening at edges

Formula: output = original + (original - blurred) × threshold

Performance

• Fast: Gaussian blur + addition
• Small images (less than 1MP): ~80-120ms
• Medium images (5MP): ~200-300ms
• Large images (greater than 10MP): ~400-600ms
• Larger sigma = slightly slower

Artifacts to Watch For

Halos: Bright edges around dark objects

• Cause: Too much sharpening
• Solution: Reduce sigma

Noise amplification: Grainy appearance

• Cause: Sharpening noisy images
• Solution: Denoise first

Edge ringing: Oscillations near edges

• Cause: Extreme sharpening
• Solution: Lower sigma, adjust flat/jagged

Best Practices

1. Sharpen Last in Workflow

Always sharpen as final step:

# Wrong order
mediaproc image sharpen photo.jpg -o sharp.jpg
mediaproc image resize sharp.jpg -w 1200

# Correct order
mediaproc image resize photo.jpg -w 1200 -o resized.jpg
mediaproc image sharpen resized.jpg -s 1.2

2. Use Lower Values for Portraits

Avoid harsh skin texture:

# Portraits (0.5-1)
mediaproc image sharpen portrait.jpg -s 0.7

3. Use Higher Values for Landscapes

Enhance texture and detail:

# Landscapes (1.5-2.5)
mediaproc image sharpen landscape.jpg -s 1.8

4. Test Before Batch Processing

Find optimal settings on sample:

# Test on one image
mediaproc image sharpen sample.jpg -s 1.5 -o test.jpg

# If good, process batch
mediaproc image sharpen "photos/*.jpg" -s 1.5

5. Don't Over-Sharpen

Too much sharpening looks artificial:

# Too much (artifacts)
mediaproc image sharpen photo.jpg -s 5

# Appropriate
mediaproc image sharpen photo.jpg -s 1.5

6. Quality Settings Matter

Use appropriate quality:

# Web (80-90)
mediaproc image sharpen photo.jpg -s 1.2 -q 85

# Print (95-100)
mediaproc image sharpen photo.jpg -s 1.5 -q 95

7. Adjust for Image Type

Portraits: Lower sigma, lower flat Landscapes: Higher sigma, higher jagged Products: Medium-high sigma Documents: High sigma, high jagged

Troubleshooting

Issue: Halos Around Objects

Problem: Bright edges around dark objects

Cause: Too much sharpening

Solution: Reduce sigma

# Halos present
mediaproc image sharpen photo.jpg -s 3

# Better
mediaproc image sharpen photo.jpg -s 1.2

Issue: Image Looks Grainy

Problem: Noise amplified

Cause: Sharpening noisy image

Solution: Denoise first or reduce sigma

# Reduce sigma
mediaproc image sharpen noisy.jpg -s 0.7

Issue: No Visible Effect

Problem: Sharpening not noticeable

Cause: Sigma too low or image already sharp

Solution: Increase sigma

# Not visible
mediaproc image sharpen photo.jpg -s 0.1

# More visible
mediaproc image sharpen photo.jpg -s 1.5

Issue: Looks Artificial

Problem: Over-sharpened appearance

Cause: Sigma too high

Solution: Reduce to natural range

# Artificial
mediaproc image sharpen photo.jpg -s 4

# Natural
mediaproc image sharpen photo.jpg -s 1.2

Issue: Edges Look Wrong

Problem: Strange edge artifacts

Cause: Jagged parameter too high

Solution: Reduce jagged value

# Too much edge sharpening
mediaproc image sharpen photo.jpg -s 2 --jagged 5

# Better
mediaproc image sharpen photo.jpg -s 2 --jagged 2

Related Commands

• blur - Opposite effect (soften images)
• auto-enhance - Automatic enhancement including sharpening
• resize - Resize images (sharpen after)
• convolve - Custom sharpening kernels

Further Reading

• Unsharp Masking
• Image Sharpening
• Gaussian Blur