🧠 Why pixel types matter

In detector simulations, not all pixels represent photon-generated signal. Some pixels exist to characterize electronic behavior, while others must be excluded from scientific analysis entirely.

Prior to this change, Pyxel supported these concepts implicitly, but they were not clearly documented in a single, conceptual location. This made it harder for contributors and users—especially those new to detector modeling—to understand how such pixels should be treated.

🔍 What changed

This merge request introduces a new documentation page under the detector background section that describes common pixel types used in imaging detectors.

• Reference pixels used for bias and readout characterization
• Masked pixels excluded from scientific analysis
• Overscan pixels specific to CCD readout

The documentation focuses on semantic interpretation rather than implementation details, keeping the explanation independent of specific detector architectures or pipeline models.

📐 Structure and placement

Pixel types are documented as part of the detector background, rather than within individual detector architectures or pipeline stages. This reflects their role as shared detector concepts rather than geometry, data containers, or configuration options.

A short cross-reference was added to the CCD architecture documentation to point readers to the new pixel types page where overscan pixels are relevant.

🌱 Why this matters

Clear documentation of detector concepts helps contributors reason correctly about calibration, analysis, and model behavior—without needing to infer intent from code or scattered references.

This change does not introduce new functionality or alter simulation behavior. It simply makes existing concepts explicit, discoverable, and easier to build upon in future development.