# Normalize feature intensities using internal standards

Normalize feature intensities by dividing them by the intensities of the
corresponding internal standards (ISTDs). Each feature must have a
defined internal standard (ISTD) in the `feature` metadata.

## Usage

``` r
normalize_by_istd(data = NULL, ignore_missing_annotation = FALSE)
```

## Arguments

- data:

  A `MRMhubExperiment` object.

- ignore_missing_annotation:

  If `FALSE`, the function will raise an error when an ISTD is not
  defined for one or more features (excluding the ISTDs themselves). If
  `TRUE`, features with missing ISTD annotations will have NA values in
  the normalized intensities.

## Value

A `MRMhubExperiment` object with normalized feature intensities