OriginLab Corporation - Data Analysis and Graphing Software - 2D graphs, 3D graphs, Contour Plots, Statistical Charts, Data Exploration, Statistics, Curve Fitting, Signal Processing, and Peak Analysis     
 
Skip Navigation Links
All BooksExpand All Books
Origin HelpExpand Origin Help
Peak AnalysisExpand Peak Analysis
Peak AnalyzerExpand Peak Analyzer

19.1.1 Peak Analyzer:Quick Start

The Peak Analyzer is a goal oriented peak analysis wizard. The major goals are as following:

Peak Analyzer Quick Start 01.png

Baseline Detection

Peak Analyzer Quick Start 22a.png

Select Create Baseline as Goal if you simply want to create a baseline. Baseline creation is a necessary step in goals Integrate Peaks, Find Peaks, Fit Peaks(Pro). There are generally two ways to create a baseline:

Click here if what you want is a step by step tutorial about how to create and subtract baseline.

Automatically Find and Treat Baseline

In Origin, baseline auto detection usually involves three steps below:

Auto Find Anchor Points for a Baseline

Select User Defined as Baseline Mode and click Find button on the bottom to auto detect anchor points.

Peak Analyzer Quick Start 08.png
  • Select 1st Derivative and 2nd Derivative when baseline is approximately constant.
  • Increase Smoothing Window Size value if further smoothing is needed for the result baseline.
  • Increase Threshold if you want to detect more anchor points.
Modify Detected Anchor Points

1. Uncheck Enable Auto Find checkbox and click Modify/Del button to enter anchor points editing mode.
2. Use mouse cursor to select or Tab, Home, End keys to navigate to desired points.
3. While the point is highlighted, keep mouse click pressed to drag or use four Arrow keys to move it stepwise.

Peak Analyzer Quick Start 09.png
Fit a Baseline

1. Select Fitting(Pro) as anchor points connection method.
2. Select a fitting function from Function drop-down list to fit.

Peak Analyzer Quick Start 10.png

Read this tutorial to learn to fit a baseline step by step.

Create a Baseline

Commonly Used Baseline Types

Origin also provides commonly used baseline types as listed in table below:

Baseline Type Descriptions Examples
Constant Use one of the statistical values or a given value as constant baseline. Peak Analyzer Quick Start 02.png
Straight Line Create a straight line as baseline by setting the Y intercept and slope. The default value of A(Intercept) and B(Slope) is obtained by connecting the two end points of the data. Peak Analyzer Quick Start 04.png
Use Existing Dataset Use existing dataset as baseline. Peak Analyzer Quick Start 05.png
End Points Weighted Create a baseline by weighting certain fraction of the end points.  :Peak Analyzer Quick Start 06.png
Min&Max Positive peaks will use Minimum value as baseline while negative peaks use Maximum. Only available when Goal is Find Peaks. Peak Analyzer Quick Start 03.png


Baseline for X-ray Photoemission Spectroscopy (XPS)

Create baseline for XPS using Shirley or Tougaard method and adjust corresponding parameters to optimize.

Peak Analyzer Quick Start 07.png

Read the algorithms of Shirley and Tougaard to know each baseline mode.

Baseline Detected by Asymmetric Least Squares Smoothing Method

Create baseline using Asymmetric Least Squares (ALS) Smoothing method and adjust corresponding parameters to optimize. The asymmetric factor should be chosen close to 0 for positive peaks, eg., 0.001, and close to 1 for negative peaks, eg.,0.99.

Peak Analyzer Quick Start ALS.png


Peak Finding

Peak Analyzer Quick Start 23a.png

In Origin, peak finding generally involves three steps possibly one more below:


Click here if you want to know a step by step example about finding and marking peaks right away.

Find Ordinary Peaks

Select one of the three peak finding methods listed below and click Find button to auto detect ordinary peaks.

Peak Finding Method Descriptions Example
Local Maximum Compare nearest N neighbors and find the maximum. Peak Analyzer Quick Start 11.png
Window Search Find the maximum value in given search window. Window can be defined in absolute values or percentage value with respect to total width and maximum height. Peak Analyzer Quick Start 12.png
First Derivative Find where first derivative is equal to 0. Offer options to smooth original data before calculating 1st derivative so as to accurately find peak position(s). Peak Analyzer Quick Start 13.png

Find Hidden Peaks

Select one from two methods listed below and click Find button to auto detect hidden peaks.

Peak Finding Method Descriptions Example
Second Derivative Find hidden peaks by detecting local extrema in second derivative of raw/smoothed data. Peak Analyzer Quick Start 14.png
Residual after 1st Derivative Calculate the residuals between spectrum data and cumulated fitting data and find hidden peaks by detecting residuals greater than certain threshold. Peak Analyzer Quick Start 15.png

Filter Unwanted Peaks

You can filter the found peaks by number of peaks or by height of the peaks.

  • By Height -- Filter out the peaks with peak height smaller than threshold specified in Threshold Height(%) text box.
  • By Number -- Limit number of peaks to be found.
Peak Analyzer Quick Start 16.png

Add or Remove Peaks

After the peaks being filtered, you can further modify, delete, add peaks. To fine tune the positions of manually added peaks, you have fit the peaks.

Peak Analyzer Quick Start 19.png

Peak Integration

Peak Analyzer Quick Start 24a.png

Select Integrate Peaks as Goal to start. Before actually perform peak integration, you have to go through two steps below:

When all the peaks are detected, you only need to set the integration width. Available options are as following:

Click here if you want to jump into a step by step tutorial about peak integration.

Individually Set Width for Each Peak

Check Adjust on Preview Graph radio box to enable direct adjustment on graph.

Peak Analyzer Quick Start 25.png
Manually Adjust Integration Width

1. Click on the yellow rectangle to select desired peak.
2. Place mouse cursor on the edge of rectangle and when it turns drag to adjust width arbitrarily or according to coordinates displayed in Data Display Tool on the bottom.

Peak Analyzer Quick Start 26.png
Set Integration Range by Scale

1. Right click on the yellow rectangle of desire peak to select Scale....
2. Enter value in X1, X2 edit boxes in appeared Scale dialog to specify integration range.

Peak Analyzer Quick Start 27.png

Set Fixed Width for All Peaks

Directly Set a Fixed Width for All Peaks

1. Check Fix Width For All Peaks radio box.
2. Enter left half and right half widths relative to peak center in Left/Right Half Width text box respectively.

Peak Analyzer Quick Start 28.png
Adjust One Peak Width and Apply to Other Peaks

1. Check Adjust on Preview Graph radio box and adjust width of one peak.
2. Right click on the yellow rectangle around that peak and select either Apply Width to All Peaks or Set as Fixed Width to All Peaks.

Peak Analyzer Quick Start 29.png

Set Peak Width by Anchor Points

If you selected User Defined for Baseline Mode on Baseline Mode page to use the anchor points to create baseline, you are allowed to select Width by Anchor Points to use the existing adjacent anchor points to determine the width of the peaks.

Peak Analyzer Quick Start 29a.png

Peak Fitting

Peak Analyzer Quick Start 30a.png

Select Fit Peaks(Pro) as Goal to start. Before actually proceed to fit peaks, you have to go through two steps below:

Fitting Peaks with Built-in or User Defined Functions

Fitting Peaks with Built-in Function

You can navigate and select a built-in function from one of the peak function categories, and directly fit your curve with automatically initialized parameter values.

Peak Analyzer Quick Start 34.png
Fitting Peaks with User Defined Function

You can also defined your own peak fitting function to be used in Peak Analyzer.

Peak Analyzer Quick Start 35.png
Fit Different Datasets with Different Fitting Functions

You can fit all peaks with same fitting function or different fitting functions.

Peak Analyzer Quick Start 36.png

Fitting Peaks with Baseline

Fitting Peaks with Baseline Subtracted
Peak Analyzer Quick Start 37.png
Fitting Baseline with Peaks
Peak Analyzer Quick Start 38.png

Read this tutorial to learn how to perform peak fitting while fitting baseline simultaneously.

Controlling Fitting Parameters

You can choose to fix or share some parameters and set upper and lower bounds or linear constraints.

Fix or Share Parameters
  1. Click Fit Control button to open Peak Fit Parameters dialog.
  2. Select same group number from Share drop-down list to share parameters.
  3. Check the checkbox in Fixed column to fix certain paramters.
Peak Analyzer Quick Start 31.png

Read this tutorial to learn how to fix certain parameters and save settings for re-usage.

Set Upper and Lower Bounds
  1. Click Fit Control button to open Peak Fit Parameters dialog and go to Bounds tab.
  2. Click in desired cell in < or <= column to select operator and enter values in Lower Bounds or Upper Bounds accordingly.
Peak Analyzer Quick Start 32.png

Read this tutorial to learn how to share status of multiple peak parameters simultaneously.

Set Linear Constraints
  1. Click Fit Control button to open Peak Fit Parameters dialog and go to Fit Control tab.
  2. Check Enable Constraints checkbox to enable editing Constraints text box.
  3. Input constraints in Constraints text box.
Peak Analyzer Quick Start 33.png

Go to this table to learn how to write linear constraints.

See Also


Topics covered in this section:

 

© OriginLab Corporation. All rights reserved.