---
title: "Signal vs Noise — The Core Challenge"
canonical: https://stackingstarlight.com/start-here/signal-vs-noise
description: "Every image is signal plus noise. The whole workflow exists to raise signal-to-noise ratio (SNR) so faint detail emerges."
---

# Signal vs Noise — The Core Challenge

> Every image is signal plus noise. The whole workflow exists to raise signal-to-noise ratio (SNR) so faint detail emerges.

Signal is the real light you want; noise is random variation that hides it. The metric that matters is **signal-to-noise ratio (SNR)**. Random noise grows with the square root of the number of frames, while signal grows linearly — so stacking N frames improves SNR by √N. Fixed-pattern noise (the same every frame) is removed by calibration instead. Understanding which noise is random and which is fixed tells you whether to *collect more* (stacking) or *calibrate it out* (bias/dark/flat frames).

---

Source: [https://stackingstarlight.com/start-here/signal-vs-noise](https://stackingstarlight.com/start-here/signal-vs-noise) · Part of [Stacking Starlight](https://stackingstarlight.com) by Michael Kalika.

LLM resources: [LLM index (llms.txt)](https://stackingstarlight.com/llms.txt) · [Complete LLM text (llms-full.txt)](https://stackingstarlight.com/llms-full.txt) · [Markdown homepage (index.md)](https://stackingstarlight.com/index.md)