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Sharpen image online

Sharpen images online with 3×3 or 5×5 convolution masks. Image sharpening for slightly soft photos—strength 0–100, live preview, free PNG download in your browser.

What is image sharpening?

Image sharpening boosts edge contrast with a convolution mask so boundaries look crisper—useful when you want to unblur pics slightly or make a picture clearer before export. Strength controls how much contrast is added at edges; 3×3 vs 5×5 sets how far the filter looks. It is not AI deblurring: heavy motion blur or pixelation need other tools. Upload, adjust, preview, download PNG—all processing runs in your browser.

Sharpen controls

Mask size and strength for image sharpening and clarity.

  1. 3×3 or 5×5 mask: Pick convolution mask size to match fine or broad sharpening.
  2. Strength 0 to 100: Control how strongly edges are enhanced.
  3. Cross convolution: Enhances edges using normalized cross-shaped kernels.
  4. Live preview: Preview updates as you adjust mask and strength.
  5. Side-by-side comparison: Original and sharpened images shown together.
  6. PNG download: Save the result as sharpen-image.png.

How to make a photo more clear

Steps for online image sharpening and mild unblur.

  1. Upload the image: Drop or click in the input panel (15 MB max).
  2. Choose mask size: Use 3×3 for text and fine detail; 5×5 for broader sharpening.
  3. Set strength: Move the slider until edges look crisp without halos.
  4. Download PNG: Save when the preview looks clear enough.

Tips for sharpening

Avoid halos and noise when making images clearer.

  1. Start moderate: Try strength 40–60 before pushing higher values.
  2. Pick mask by subject: 3×3 for text and fine lines; 5×5 for larger objects.
  3. Watch for halos: If bright outlines appear around edges, lower strength.
  4. Noise gets sharper too: Grainy photos may look noisier—denoise first if needed.
  5. Compare at zero: Set strength to 0 to judge how much clarity you added.
  6. Export PNG for logos: Alpha is preserved when sharpening icons or cutouts.

When to sharpen images

Typical uses for making photos and scans clearer.

  1. Soft phone photos: Add clarity to slightly soft mobile camera shots.
  2. Web product images: Make SKU photos look crisper on catalog pages.
  3. Scanned documents: Improve legibility on mildly fuzzy scans and blurry text.
  4. Social thumbnails: Boost edge pop before posting compressed JPEGs.
  5. Screenshot cleanup: Clarify UI captures that look slightly blurred.
  6. Pre-export prep: Sharpen once before uploading to another platform.

Why use this sharpen tool

Benefits of free browser-based image sharpening.

  1. Mask choice: Match sharpening radius to your subject with 3×3 or 5×5.
  2. Private: Images stay on your device—no server upload.
  3. Instant preview: See sharpening strength before download.
  4. Preserves alpha: Transparency on PNG uploads is kept intact.
  5. No install: Works in any modern browser—make pictures clearer without Photoshop.
  6. Free: Unlimited previews and downloads.

Technical details

How convolution sharpening works here.

  1. 3×3 algorithm: Pixastic-style cross kernel: center weight 15, edge weights scale with strength; normalized sum 1.
  2. 5×5 algorithm: Cross kernel at 2-pixel radius with center weight 35—broader neighbor sampling.
  3. Color channels: Sharpen R, G, B independently; alpha unchanged.
  4. Rendering: Canvas 2D getImageData / putImageData.
  5. Input limits: 15 MB; longest edge 8192 px.
  6. Browser support: Chromium, Firefox, Safari with Canvas 2D.

Frequently Asked Questions

Have questions? We have answers.

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