# Median Pass Filter

Apply median pass filter to remove noise while preserving edges with multiple algorithms

> Canonical page: https://elysiatools.com/en/tools/image-median-pass

- **Category:** Design

- **Keywords:** image, median, filter, noise, denoise, salt-pepper, speckle, preserve

## Overview

The Median Pass Filter is a powerful image processing tool designed to effectively remove noise, such as salt-and-pepper or speckle artifacts, while maintaining sharp edges and critical image details.

## Inputs

- **Image File** (file): Upload any image file (JPEG, PNG, WebP, GIF, BMP, TIFF) to remove noise while preserving edges
- **Median Algorithm** (select): Choose median filter algorithm. Standard works well for most noise types
- **Kernel Size** (range): Size of the median filter kernel (must be odd). Larger kernels remove more noise but may blur details
- **Filter Iterations** (number): Number of median filter passes. More iterations = stronger noise reduction
- **Noise Threshold** (range): Sensitivity for noise detection. Higher values filter less aggressively
- **Preserve Edges** (checkbox): Maintain edge detail while removing noise
- **Channel Processing** (select): Choose which color channels to process
- **Output Format** (select): Choose output format or keep original. PNG recommended for maximum quality
- **Quality (1-100)** (number): Output quality for lossy formats (JPEG, WebP). Higher = better quality but larger file size

## When to use

- Removing digital noise from low-light or high-ISO photographs.
- Cleaning up scanned documents that contain speckle or grain artifacts.
- Smoothing textures in images while preserving structural boundaries.

## How it works

- Upload your image file and select the preferred median algorithm, such as Standard or Bilateral.
- Adjust the kernel size and iteration count to control the intensity of the noise reduction.
- Enable edge preservation settings to ensure that fine details remain sharp during the filtering process.
- Download your processed image in your chosen format, such as PNG or WebP, with optimized quality settings.

## Use cases

- Restoring old, grainy scanned photos by removing digital artifacts.
- Cleaning up medical or scientific imaging data where noise interferes with analysis.
- Pre-processing images for computer vision tasks to improve feature detection accuracy.

## Frequently asked questions

### What is the difference between Standard and Bilateral median filters?

Standard median filters are excellent for general noise reduction, while Bilateral filters are specifically designed to preserve edges by considering pixel intensity differences.

### Why must the kernel size be an odd number?

The median filter calculates the middle value of a pixel neighborhood; an odd-sized kernel ensures there is a single central pixel to represent the median value.

### Will this tool reduce the resolution of my image?

No, the tool processes pixel values to remove noise but does not change the dimensions or resolution of your original image file.

### Can I process specific color channels?

Yes, you can choose to apply the filter to all channels, or isolate processing to luminance, chrominance, or the alpha channel only.

### What is the maximum file size I can upload?

You can upload image files up to 20MB in size, including formats like JPEG, PNG, WebP, GIF, BMP, and TIFF.

## Related tools

- [Image Morphological Opening](https://elysiatools.com/en/tools/image-open): Apply morphological opening operation (erosion followed by dilation) to remove small noise and separate connected objects
- [Image Motion Blur Kernel](https://elysiatools.com/en/tools/image-motion-blur-kernel): Apply motion blur kernel to simulate camera movement or object motion in specified direction
- [Image Noise Reduction](https://elysiatools.com/en/tools/image-noise-reduction): Reduce image noise using multiple algorithms including median, gaussian, and bilateral filtering
- [Image Trim Whitespace](https://elysiatools.com/en/tools/image-trim-whitespace): Remove whitespace and empty margins from images by detecting and trimming blank areas
- [Image Translation](https://elysiatools.com/en/tools/image-translation): Apply translation transformation to move images horizontally and vertically. Visualize the translation matrix and see how pixel coordinates shift.
- [Parallax Animation Generator](https://elysiatools.com/en/tools/image-parallax): Generate parallax animations from images. Creates depth-based animation where different layers move at different speeds, creating a 3D effect.
- [Remove Image Background](https://elysiatools.com/en/tools/image-background-remover): Remove image backgrounds and export a transparent PNG
- [Image Gradient Overlay](https://elysiatools.com/en/tools/image-add-gradient): Add gradient overlay effects to images with customizable colors, directions, and blend modes

## Samples

- [Web Image Processing Python Samples](https://elysiatools.com/en/samples/web-image-processing-python): Web Python image processing examples using PIL/Pillow including reading, saving, resizing, and format conversion
- [Web Image Processing TypeScript Samples](https://elysiatools.com/en/samples/web-image-processing-typescript): Web TypeScript image processing examples including image read/save, scaling, and format conversion
- [Android Image Processing Java Samples](https://elysiatools.com/en/samples/android-image-processing-java): Android Java image processing examples including reading/saving images, scaling, and format conversion
- [Android Image Processing Kotlin Samples](https://elysiatools.com/en/samples/android-image-processing-kotlin): Android Kotlin image processing examples including reading/saving images, scaling, and format conversion

## Related content

- [Image Cleanup, Resizing, and Detail Enhancement](https://elysiatools.com/en/hubs/image-cleanup-resize-and-detail-enhancement): Prepare reviewed images for delivery by fixing orientation, trimming edges, reducing noise, resizing precisely, and restoring crisp detail.