Equalize Image (Area)

About Histogram Equalization

Histogram equalization is a powerful image processing technique that enhances contrast by redistributing pixel intensities across the entire tonal range. This tool allows you to apply equalization to the entire image or select specific areas for targeted enhancement.

How to Use the Equalize Image Tool

1. Upload your image or load from a URL
2. Choose between "Whole Image" or "Select Area" mode
3. For whole image: Click "Equalize Entire Image"
4. For area selection: Click and drag to select specific regions
5. Apply equalization to multiple areas if needed
6. Download your enhanced image in PNG, JPEG, or WebP format

Best Uses for Histogram Equalization

• Enhance underexposed or dark photographs
• Improve visibility of details in shadows
• Process medical imaging (X-rays, MRIs, CT scans)
• Enhance surveillance and security camera footage
• Improve low-contrast scientific images
• Reveal hidden details in scanned documents
• Process night photography or low-light images
• Enhance historical photo restoration

Understanding Histogram Equalization

Histogram equalization works by analyzing the distribution of pixel intensities (the histogram) in an image and redistributing them to achieve a more uniform distribution. This process:

• Analyzes Brightness: Calculates the frequency of each brightness level
• Creates CDF: Builds a cumulative distribution function
• Remaps Values: Redistributes pixel intensities to span the full range
• Preserves Details: Maintains relative brightness relationships