What counts as a 'stray' pixel?

Any non-transparent pixel that has fewer than the chosen minimum number of non-transparent 8-connected neighbors (the 8 pixels surrounding it). Pixels below that threshold are treated as noise and made transparent.

Will this remove parts of the actual signature?

It shouldn't, as long as the minimum-neighbors setting isn't set too high — a real stroke's pixels almost always have several opaque neighbors along the line, unlike isolated scanner noise.

When should I use this instead of the low-quality improver?

Use this specifically for scattered single-pixel speckle near the edges, often left behind after a background-removal step. The low-quality improver is a broader pipeline that also boosts contrast and sharpness.

Does it change the color of any pixel?

No, it only ever sets a pixel's alpha to 0 (fully transparent); it never changes RGB color values.

Signature Edges Cleaner - Remove Speckle Noise from a Signature

Overview

Introduction

This tool removes stray, isolated speckle pixels from around a signature's edges entirely in your browser.

It's especially useful right after a background-removal step, which can leave behind scattered single-pixel artifacts along the boundary.

What Is Signature Edges Cleaner?

A client-side despeckle tool that examines each non-transparent pixel's 8 surrounding neighbors and clears any pixel that has too few non-transparent neighbors.

It's a simple, local noise filter, not a full denoising algorithm.

How Signature Edges Cleaner Works

For every non-transparent pixel, the tool counts how many of its 8 surrounding pixels are also non-transparent. If that count is below the chosen minimum, the pixel is treated as noise and its alpha is set to 0.

Because the check only looks at immediate neighbors, it catches isolated single pixels and small clumps without affecting the connected body of a real stroke.

When To Use Signature Edges Cleaner

Use it right after removing a signature's background, when a color-key or chroma-key step often leaves a few stray colored pixels behind near the edges.

It's also useful for cleaning up scanner dust artifacts around a signature scan.

Often used alongside Low-quality Signature Improver and Signature Background Remover.

Features

Advantages

Targets exactly the kind of noise a background-removal step tends to leave behind.
Simple, predictable neighbor-count logic that's easy to tune.
Runs entirely client-side.

Limitations

A minimum-neighbors setting that's too aggressive can start eating into thin, sparse parts of a real signature stroke.
It only removes speckle near existing non-transparent pixels; it can't fix a background that wasn't keyed out at all.

Examples

Cleaning post-background-removal speckle

Input

A signature with a few stray colored pixels left after chroma-keying

Output

A cleaner signature with the isolated pixels made transparent

Pixels with fewer than the minimum opaque neighbors get cleared, removing the scattered speckle.

A dense stroke stays intact

Input

A thick signature stroke where every pixel has several opaque neighbors

Output

The stroke unchanged

Pixels within a connected stroke almost always meet the minimum-neighbors threshold and are left alone.

Best Practices & Notes

Best Practices

Run this right after a background-removal step, while speckle is freshest.
Start with the default minimum of 2 neighbors and only raise it if visible speckle remains.

Developer Notes

This tool is a thin wrapper around the shared cleanPngEdges function; the neighbor-counting despeckle math is identical regardless of whether the subject is a signature or any other PNG.

Signature Edges Cleaner Use Cases

Cleaning up leftover speckle after a chroma-key background removal
Removing scanner dust artifacts around a signature's edges
Tidying a signature before compositing it onto a document

Common Mistakes

Setting the minimum-neighbors threshold too high and accidentally erasing thin, sparse stroke tips.
Expecting this to fix a background that was never keyed out — it only removes small isolated speckle, not large solid regions.

Tips

Pair with a background-removal tool as a two-step cleanup pass.
If the signature has very thin strokes, keep the minimum-neighbors setting low (1-2) to avoid eroding them.

Signature Edges Cleaner