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CLAHE Histogram Equalization

Apply Contrast Limited Adaptive Histogram Equalization for local contrast enhancement

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 apply CLAHE histogram equalization

4 64 256

Size of tiles for local histogram equalization. Smaller tiles provide more local contrast enhancement

1 3 10

Contrast amplification limit. Higher values allow stronger contrast enhancement but may amplify noise

0.001 0.01 0.1

Brightness amplification limit. Lower values prevent over-amplification of bright areas

2 8 16

Number of grid divisions. Higher values create more tiles for finer local enhancement

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, range, select, number
Output Type
file
Sample Coverage
4
API Ready
Yes

Overview

Enhance the visual clarity of your images using Contrast Limited Adaptive Histogram Equalization (CLAHE). This tool improves local contrast by dividing images into tiles, allowing you to reveal hidden details in underexposed or low-contrast areas without over-amplifying noise.

When to Use

  • •Improving visibility in medical or scientific imagery where subtle details are obscured by low contrast.
  • •Restoring clarity to photos taken in challenging lighting conditions, such as deep shadows or hazy environments.
  • •Preparing images for computer vision tasks by normalizing contrast across different regions of a frame.

How It Works

  • •Upload your image file in any standard format like PNG, JPEG, or TIFF.
  • •Adjust the Tile Size and Grid Size to define the local area for contrast calculation.
  • •Fine-tune the Contrast Limit and Brightness Limit to balance enhancement strength against potential noise.
  • •Select your preferred output format and quality settings, then download the processed image.

Use Cases

Enhancing medical X-rays or scans to better visualize tissue structures.
Correcting underexposed landscape photography to bring out shadow detail.
Preprocessing surveillance footage to improve object detection in low-light conditions.

Examples

1. Restoring Shadow Detail in Photography

Photographer
Background
A landscape photo was taken during sunset, resulting in deep, featureless shadows in the foreground.
Problem
The foreground details are lost due to low contrast in the dark areas.
How to Use
Upload the image and set a moderate Tile Size of 64 with a Contrast Limit of 3.0 to gently lift the shadows.
Example Config
tileSize: 64, contrastLimit: 3.0
Outcome
The foreground textures become visible and well-defined without washing out the bright sky.

2. Medical Imaging Clarity

Researcher
Background
A grayscale medical scan contains subtle features that are difficult to distinguish from the background noise.
Problem
Global contrast adjustments make the image too harsh, obscuring the specific features needed for analysis.
How to Use
Use a smaller Tile Size of 32 and a lower Contrast Limit to focus on local feature enhancement.
Example Config
tileSize: 32, contrastLimit: 2.0
Outcome
Local structures are significantly clearer, allowing for more accurate observation of the scan data.

Try with Samples

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FAQ

What is CLAHE?

CLAHE stands for Contrast Limited Adaptive Histogram Equalization. It is an image processing technique that enhances contrast locally rather than globally, preventing the over-amplification of noise.

How does the Tile Size affect my image?

Smaller tile sizes provide more localized contrast enhancement, which is great for fine details, while larger tiles provide a smoother, more global-like adjustment.

Will this tool increase image noise?

High contrast limit settings can amplify noise. If your image appears grainy after processing, try lowering the Contrast Limit value.

Which file formats are supported?

You can upload JPEG, PNG, WebP, GIF, BMP, and TIFF files. You can also choose to convert your output to a different format.

Is there a limit to the file size?

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

API Documentation

Request Endpoint

POST /en/api/tools/image-clahe

Request Parameters

Parameter Name Type Required Description
imageFile file (Upload required) Yes Upload any image file (JPEG, PNG, WebP, GIF, BMP, TIFF) to apply CLAHE histogram equalization
tileSize range No Size of tiles for local histogram equalization. Smaller tiles provide more local contrast enhancement
contrastLimit range No Contrast amplification limit. Higher values allow stronger contrast enhancement but may amplify noise
brightnessLimit range No Brightness amplification limit. Lower values prevent over-amplification of bright areas
gridSize range No Number of grid divisions. Higher values create more tiles for finer local enhancement
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-clahe 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-clahe": {
      "name": "image-clahe",
      "description": "Apply Contrast Limited Adaptive Histogram Equalization for local contrast enhancement",
      "baseUrl": "https://elysiatools.com/mcp/sse?toolId=image-clahe",
      "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]