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Image Normalise

Normalise image histogram to enhance contrast by stretching the intensity range (British spelling)

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 normalisation

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 Normalise is a professional utility designed to enhance image contrast by stretching the intensity range of your image histogram. By remapping pixel values, this tool helps reveal hidden details in shadows and highlights, ensuring your visuals appear balanced and vibrant.

When to Use

  • •When an image appears washed out or lacks sufficient contrast.
  • •When you need to recover detail from underexposed or overexposed photos.
  • •When preparing images for print or digital display that require standardized intensity levels.

How It Works

  • •Upload your image file (JPEG, PNG, WebP, GIF, BMP, or TIFF).
  • •Enable Auto Contrast for a quick, balanced enhancement, or manually adjust the lower and upper percentiles to target specific shadow and highlight ranges.
  • •Select your preferred output format and quality settings.
  • •Process the file to download your contrast-enhanced image.

Use Cases

Restoring clarity to scanned documents or faded historical photographs.
Improving the visual impact of product photography for e-commerce listings.
Standardizing image intensity across a batch of photos for consistent presentation.

Examples

1. Enhancing Faded Scanned Documents

Archivist
Background
A collection of old, low-contrast scanned documents that are difficult to read due to greyish backgrounds.
Problem
The text lacks definition against the paper background, making it hard to transcribe.
How to Use
Upload the scan, disable Auto Contrast, and set the lower percentile to 5% to darken the text while keeping the background clean.
Example Config
lowerPercentile: 5, upperPercentile: 95, format: 'png'
Outcome
The text becomes significantly darker and sharper, making the document legible for digital archiving.

2. Optimizing Product Photos

E-commerce Manager
Background
Product photos taken in suboptimal lighting appear dull and lack the 'pop' required for a professional storefront.
Problem
The images look flat and fail to highlight the product's texture and color depth.
How to Use
Upload the product image and use the default Auto Contrast settings to instantly stretch the histogram.
Example Config
autoContrast: true, format: 'webp', quality: 90
Outcome
The product image gains depth and vibrant contrast, resulting in a more professional appearance for the website.

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FAQ

What does histogram normalisation do?

It stretches the range of intensity values in an image so that the darkest pixels become black and the brightest pixels become white, effectively increasing the overall contrast.

Should I use Auto Contrast?

Yes, Auto Contrast is recommended for most images as it automatically calculates the optimal 1% and 99% percentiles to improve clarity without clipping important details.

How do the percentile sliders affect my image?

The lower percentile ignores a percentage of the darkest pixels to preserve shadow detail, while the upper percentile ignores a percentage of the brightest pixels to protect highlight detail.

Which output format should I choose?

PNG is recommended for maximum quality, while JPEG or WebP are better if you need to balance file size with visual fidelity.

Is there a file size limit?

Yes, the tool supports files up to 20MB.

API Documentation

Request Endpoint

POST /en/api/tools/image-normalise

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 normalisation
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-normalise 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-normalise": {
      "name": "image-normalise",
      "description": "Normalise image histogram to enhance contrast by stretching the intensity range (British spelling)",
      "baseUrl": "https://elysiatools.com/mcp/sse?toolId=image-normalise",
      "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]