R: Find peaks in a spectrum

find_peaks {photobiology} | R Documentation

## Find peaks in a spectrum

### Description

This function finds all peaks (local maxima) in a spectrum, using a user selectable size threshold relative to the tallest peak (global maximum). This a wrapper built on top of function peaks from package splus2R.

### Usage

    find_peaks(x, ignore_threshold = 0, span = 3, strict = TRUE,
      na.rm = FALSE)

### Arguments

`x` | numeric vector
`ignore_threshold` | numeric value between 0.0 and 1.0 indicating the size threshold below which peaks will be ignored.
`span` | a peak is defined as an element in a sequence which is greater than all other elements within a window of width span centered at that element. The default value is 3, meaning that a peak is bigger than both of its neighbors. Default: 3.
`strict` | logical flag: if TRUE, an element must be strictly greater than all other values in its window to be considered a peak. Default: TRUE.
`na.rm` | logical indicating whether `NA` values should be stripped before searching for peaks.

### Value

an object like s.irrad of logical values. Values that are TRUE correspond to local peaks in the data.

### Note

This function is a wrapper built on function `peaks` from splus2R and handles non-finite (including NA) values differently than `peaks`, instead of giving an error they are replaced with the smallest finite value in `x`.

### See Also

`peaks`

Other peaks and valleys functions: `get_peaks`, `peaks`, `valleys`

### Examples

    with(sun.data, w.length[find_peaks(s.e.irrad)])

[Package photobiology version 0.9.21 Index]