PNG to HSI Colors Converter

Uploads a PNG, tallies every distinct RGBA color it contains, converts each to HSI (hue, saturation, intensity) using the standard image-processing formula, and produces a plain-text report sorted by frequency, entirely client-side. A free online tool from Staaarter, right in your browser.

Runs locallyUpdated 2026-07-26

Overview

Introduction

This tool scans every pixel of an uploaded PNG and reports its colors converted to HSI, a color model common in image processing and computer vision work.

Its intensity channel is a simple average of the RGB channels, making it useful when you specifically want brightness that isn't biased toward any one channel.

What Is PNG to HSI Colors Converter?

A client-side color analysis tool that decodes a PNG, tallies its distinct RGBA colors, and converts each one to HSI using the standard image-processing formula.

The output is a readable plain-text report rather than raw pixel data, capped at the 256 most frequent colors for readability.

How PNG to HSI Colors Converter Works

Every pixel's exact RGBA value is counted in a frequency map; the resulting unique colors are sorted from most to least common.

Each color's intensity is the plain average of its R, G, and B channels; saturation compares the minimum channel to that average; hue is computed using the standard arccos-based angle formula distinct from HSL/HSV's max-channel approach.

When To Use PNG to HSI Colors Converter

Use it when working with image-processing or computer-vision pipelines that expect HSI input.

It's also useful for understanding an image's brightness distribution using a channel-neutral average rather than HSV's max-channel bias.

Features

Advantages

  • Runs entirely client-side; your image is never uploaded to a server.
  • Groups identical colors together with counts, rather than dumping every pixel individually.
  • Uses the true HSI arccos hue formula rather than approximating it with the HSL/HSV formula.

Limitations

  • The report caps out at the 256 most frequent unique colors; images with huge color diversity (like photos) will have many rarer colors omitted.
  • HSI is less common in everyday design tools than HSL or HSV, so cross-referencing values in a typical color picker may not be straightforward.

Examples

Analyze a flat-color icon

Input

A 64x64 PNG icon using 3 solid colors

Output

A report listing exactly 3 rgba/hsi rows with pixel counts

Simple graphics with flat colors produce a short, exact report.

Analyze a grayscale image

Input

A PNG with only gray pixels

Output

Rows showing 0% saturation at varying intensity levels

Colors with equal R, G, B channels have zero HSI saturation by definition.

Best Practices & Notes

Best Practices

  • Use this when your downstream processing pipeline specifically expects HSI rather than HSL/HSV.
  • Remember intensity is a plain average, so it can differ noticeably from HSV's value for saturated colors.

Developer Notes

The hue/saturation/intensity math is a pure, individually-exported function (rgbToHsi) implementing the true arccos-based HSI hue formula (not a reuse of the HSL/HSV max-channel formula), so it's directly unit-testable against known reference colors.

PNG to HSI Colors Converter Use Cases

  • Feeding pixel color data into an image-processing pipeline that expects HSI
  • Comparing HSI intensity against HSV value for the same image to see how they diverge
  • Studying color distribution in scientific or remote-sensing imagery

Common Mistakes

  • Assuming HSI's intensity is the same as HSL's lightness or HSV's value — all three compute brightness differently and will show different numbers for the same color.
  • Expecting an exhaustive per-pixel list on a large photographic image — the report is intentionally capped and frequency-sorted instead.

Tips

  • If you need a specific image-processing library's exact HSI convention, double check its formula matches this arccos-based one before comparing values directly.
  • Pair this with the transparency checker if you also need to know which colors are semi-transparent.

References

Frequently Asked Questions