Localmax: Difference between revisions

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===Purpose===
===Purpose===
Automated identification of local maxima
Automated identification of local maxima
===Synopsis===
===Synopsis===
:i0 = localmax(x,w)
:i0 = localmax(x,w)
===Description===
===Description===
Finds maxima in windows of width (w). Wider windowing is used to avoid local maxima that might be due to noise. The default window width is w=3. This function is called by PEAKFIND.
Finds maxima in windows of width (w). Wider windowing is used to avoid local maxima that might be due to noise. The default window width is w=3. This function is called by PEAKFIND.
====INPUTS====
====INPUTS====
* '''x''' =  matrix of measured traces containing peaks each  row of (x) is an individual trace.
* '''x''' =  matrix of measured traces containing peaks each  row of (x) is an individual trace.
====OPTIONAL INPUTS====
====OPTIONAL INPUTS====
* '''w''' = odd scalar window width for determining local maxima {default: w = 3}.
* '''w''' = odd scalar window width for determining local maxima {default: w = 3}.
====OUTPUTS====
====OUTPUTS====
* '''i0''' =  cell w/ indices of the location of the major peaks for each of the  traces in each cell.
* '''i0''' =  cell w/ indices of the location of the major peaks for each of the  traces in each cell.
===Examples===
===Examples===
:load nir_data
:load nir_data
:plot(spec1.axisscale{2},spec1.data(1,:))
:plot(spec1.axisscale{2},spec1.data(1,:))
:i0 = localmax(spec1.data(1,:));
:i0 = localmax(spec1.data(1,:));
:vline(spec1.axisscale{2}(i0{1}))
:vline(spec1.axisscale{2}(i0{1}))
:i0 = localmax(spec1.data(1,:),5);
:i0 = localmax(spec1.data(1,:),5);
:vline(spec1.axisscale{2}(i0{1}),'r')
:vline(spec1.axisscale{2}(i0{1}),'r')
===See Also===
===See Also===
[[fitpeaks]], [[peakfind]]
[[fitpeaks]], [[peakfind]]

Revision as of 15:25, 3 September 2008

Purpose

Automated identification of local maxima

Synopsis

i0 = localmax(x,w)

Description

Finds maxima in windows of width (w). Wider windowing is used to avoid local maxima that might be due to noise. The default window width is w=3. This function is called by PEAKFIND.

INPUTS

  • x = matrix of measured traces containing peaks each row of (x) is an individual trace.

OPTIONAL INPUTS

  • w = odd scalar window width for determining local maxima {default: w = 3}.

OUTPUTS

  • i0 = cell w/ indices of the location of the major peaks for each of the traces in each cell.

Examples

load nir_data
plot(spec1.axisscale{2},spec1.data(1,:))
i0 = localmax(spec1.data(1,:));
vline(spec1.axisscale{2}(i0{1}))
i0 = localmax(spec1.data(1,:),5);
vline(spec1.axisscale{2}(i0{1}),'r')

See Also

fitpeaks, peakfind