Categories

← View All Tools

Image Normalize

Normalize image histogram to enhance contrast by stretching the intensity range

Click to upload file or drag and drop file here

Maximum file size: 20MB Supported formats: image/jpeg, image/png, image/webp, image/gif, image/bmp, image/tiff

Upload any image file (JPEG, PNG, WebP, GIF, BMP, TIFF) to enhance contrast through histogram normalization

Automatically enhance contrast using 1% and 99% percentiles (recommended for most images)

0.1 1 10

Percentage of darkest pixels to ignore (0.1% - 10%). Lower values preserve more shadow detail

90 99 99.9

Percentage of brightest pixels to ignore (90% - 99.9%). Higher values preserve more highlight detail

Choose output format or keep original. PNG recommended for maximum quality

Output quality for lossy formats (JPEG, WebP). Higher = better quality but larger file size

Key Facts

Category
Design
Input Types
file, checkbox, range, select, number
Output Type
file
Sample Coverage
4
API Ready
Yes

Overview

Image Normalize is a professional-grade utility designed to enhance image contrast by stretching the pixel intensity range across the full histogram spectrum. By remapping the darkest and brightest values, this tool effectively clarifies washed-out photos and improves visual depth without requiring complex editing software.

When to Use

  • •Correcting images that appear flat, dull, or lack sufficient contrast.
  • •Standardizing visual consistency across a batch of images with varying lighting conditions.
  • •Preparing images for analysis by maximizing the dynamic range of pixel intensities.

How It Works

  • •Upload your image file (JPEG, PNG, WebP, GIF, BMP, or TIFF).
  • •Enable 'Auto Contrast' for a standard enhancement or manually adjust the lower and upper percentiles to define your intensity range.
  • •Select your preferred output format and quality settings.
  • •Process the image to instantly download the contrast-enhanced version.

Use Cases

Restoring old or faded scanned documents to make text more legible.
Enhancing low-contrast photography taken in overcast or hazy conditions.
Optimizing medical or scientific imagery for better feature visibility.

Examples

1. Enhancing Faded Scanned Documents

Archivist
Background
A collection of historical documents was scanned, but the resulting images appear grey and washed out, making the text difficult to read.
Problem
The text lacks sufficient contrast against the background, hindering readability.
How to Use
Upload the scanned image and adjust the lower percentile to 2% to clip the dark background noise, then process the file.
Example Config
Auto Contrast: Off, Lower Percentile: 2, Upper Percentile: 99
Outcome
The text becomes sharp and dark against a clean white background, significantly improving legibility.

2. Optimizing Hazy Landscape Photos

Photographer
Background
A series of landscape photos taken on a foggy day lack depth and appear flat.
Problem
The image histogram is compressed, resulting in a lack of true blacks and whites.
How to Use
Use the Auto Contrast feature to automatically stretch the intensity range to the full spectrum.
Example Config
Auto Contrast: On, Format: PNG
Outcome
The image gains vibrant contrast, with deeper shadows and brighter highlights that restore the intended visual impact.

Try with Samples

image, png, jpg
Web Image Processing Python Samples
Web Python image processing examples using PIL/Pillow including reading, saving, resizing, and format conversion
title token image
image
Windows Image Processing C++ Samples
Windows C++ image processing examples including reading/saving images, resizing, and format conversion using Windows Imaging Component (WIC)
title token image
image
Web Image Processing Rust Samples
Web Rust image processing examples including image read/save, scaling, and format conversion
title token image
image
macOS Image Processing Objective-C Samples
macOS Objective-C image processing examples including image reading/saving, image scaling, and format conversion
title token image
image

Related Hubs

Image Convert Tools
Explore 100 image tools for convert workflows and compare closely related utilities quickly.
Image Tools
Explore 40 image tools for utility workflows and compare closely related utilities quickly.
Json Convert Tools
Explore 100 json tools for convert workflows and compare closely related utilities quickly.
Audio Convert Tools
Explore 100 audio tools for convert workflows and compare closely related utilities quickly.

FAQ

What does histogram normalization do?

It stretches the intensity range of an image so that the darkest pixels become black and the brightest pixels become white, which significantly improves overall contrast.

How do the percentile sliders work?

The lower percentile ignores the darkest pixels, while the upper percentile ignores the brightest. This helps prevent extreme noise or outliers from skewing the contrast adjustment.

Can I change the file format?

Yes, you can convert your image to JPEG, PNG, or WebP, or choose to keep the original file format.

Is there a limit to the file size?

Yes, the tool supports image files up to 20 MB.

Does this tool reduce image quality?

The tool uses high-quality processing. You can adjust the quality setting (1-100) for lossy formats like JPEG and WebP to balance file size and visual fidelity.

API Documentation

Request Endpoint

POST /en/api/tools/image-normalize

Request Parameters

Parameter Name Type Required Description
imageFile file (Upload required) Yes Upload any image file (JPEG, PNG, WebP, GIF, BMP, TIFF) to enhance contrast through histogram normalization
autoContrast checkbox No Automatically enhance contrast using 1% and 99% percentiles (recommended for most images)
lowerPercentile range No Percentage of darkest pixels to ignore (0.1% - 10%). Lower values preserve more shadow detail
upperPercentile range No Percentage of brightest pixels to ignore (90% - 99.9%). Higher values preserve more highlight detail
format select No Choose output format or keep original. PNG recommended for maximum quality
quality number No Output quality for lossy formats (JPEG, WebP). Higher = better quality but larger file size

File type parameters need to be uploaded first via POST /upload/image-normalize to get filePath, then pass filePath to the corresponding file field.

Response Format

{
  "filePath": "/public/processing/randomid.ext",
  "fileName": "output.ext",
  "contentType": "application/octet-stream",
  "size": 1024,
  "metadata": {
    "key": "value"
  },
  "error": "Error message (optional)",
  "message": "Notification message (optional)"
}
File: File

AI MCP Documentation

Add this tool to your MCP server configuration: 

{
  "mcpServers": {
    "elysiatools-image-normalize": {
      "name": "image-normalize",
      "description": "Normalize image histogram to enhance contrast by stretching the intensity range",
      "baseUrl": "https://elysiatools.com/mcp/sse?toolId=image-normalize",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

You can chain multiple tools, e.g.: `https://elysiatools.com/mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp`, max 20 tools.

Supports URL file links or Base64 encoding for file parameters.

If you encounter any issues, please contact us at [email protected]