# Index Pixels

## Summary
Compute per-pixel bin indices (radial or azimuthal) for later 1D averaging.

## Metadata
- **Module ID:** IndexPixels
- **Module path:** /home/runner/work/MoDaCor/MoDaCor/src/modacor/modules/technique_modules/scattering/index_pixels.py
- **Module version:** 20251130.1
- **Keywords:** radial, azimuthal, pixel indexing, binning, scattering

## Required data keys
- signal
- Q
- Psi

## Modifies
- _None_

## Required arguments
- with_processing_keys
- averaging_direction

## Default configuration
```json
{
  "averaging_direction": "radial",
  "bin_type": "log",
  "n_bins": 100,
  "psi_limits_unit": null,
  "psi_max": null,
  "psi_min": null,
  "q_limits_unit": null,
  "q_max": null,
  "q_min": null,
  "with_processing_keys": null
}
```

## Argument specification
| Argument | Type | Required | Default | Description |
|---|---|---|---|---|
| `averaging_direction` | str | Yes | radial | Averaging direction: 'radial' or 'azimuthal'. |
| `bin_type` | str | No | log | Binning type: 'linear' or 'log'. |
| `n_bins` | int | No | 100 | Number of bins. |
| `psi_limits_unit` | str or NoneType | No | - | Units for psi_min/psi_max if provided. |
| `psi_max` | float or int or NoneType | No | - | Maximum Psi value for binning. |
| `psi_min` | float or int or NoneType | No | - | Minimum Psi value for binning. |
| `q_limits_unit` | str or NoneType | No | - | Units for q_min/q_max if provided. |
| `q_max` | float or int or NoneType | No | - | Maximum Q value for binning. |
| `q_min` | float or int or NoneType | No | - | Minimum Q value for binning. |
| `with_processing_keys` | str or list or NoneType | Yes | - | ProcessingData key or list of keys to index. |

## References
DOI 10.1088/0953-8984/25/38/383201

## Notes
IndexPixels computes bin indices purely from geometry (Q, Psi) and user-defined limits; Mask is not used here so it can be applied per frame in downstream steps.