Peak Detection

NMRTools provides automated peak detection for 1D NMR spectra, allowing you to identify and analyze resonances in your data. The peak detection algorithm uses signal-to-noise ratio (SNR) filtering to distinguish true peaks from background noise.

Quick Example

spec = exampledata("1D_19F")
pks = detectpeaks(spec)

Vector of 1 SimplePeak{1} objects
	Index	δ	Intensity	δfwhm
	1	-123.69808278240923	23737.674377441406	0.0626986378531874

The detectpeaks function returns a vector of SimplePeak objects with information about each detected peak:

To visualize the detected peaks, simply plot them alongside the spectrum:

plot(spec)
plot!(pks)

Detected peaks are shown as a red vertical line overlaid on the spectrum.

Basic Usage

The detectpeaks function analyzes a 1D NMR spectrum and returns a vector of SimplePeak objects:

peaks = detectpeaks(spec)

Each SimplePeak object contains three key properties:

intensity: The peak height (amplitude) in the spectrum
δ: The chemical shift position in ppm
δfwhm: The full width at half maximum (FWHM) in ppm

Adjusting Peak Detection Sensitivity

The snr_threshold parameter controls the sensitivity of peak detection by setting the minimum signal-to-noise ratio required for a peak to be detected:

# Detect only very strong peaks (SNR > 20)
peaks_strong = detectpeaks(spec; snr_threshold=20)

# More sensitive detection (SNR > 5)
peaks_sensitive = detectpeaks(spec; snr_threshold=5)

Accessing Individual Peak Properties

You can access properties of individual peaks:

julia> peak = peaks[1]
SimplePeak{1} with intensity=23737.674377441406, δ=-123.69808278240923, δfwhm=0.0626986378531874

julia> peak.δ
-123.69808278240923

julia> peak.intensity
23737.674377441406

julia> peak.δfwhm
0.0626986378531874

Sorting Peaks

You can sort peaks by various properties:

# Sort by intensity (strongest first)
sorted_by_intensity = sort(peaks; by=p -> p.intensity, rev=true)

# Sort by chemical shift (left to right)
sorted_by_shift = sort(peaks; by=p -> p.δ, rev=true)