## Contents

See more related video:Origin VT-0010 Interpolation

## Overview

The Interpolate Gadget performs quick interpolation on a ROI (Region of Interest) range.

• Easily interpolate data points on a rectangular region with the linear, cubic spline or cubic B-spline method.
• Quickly find out an interpolated Y value from any given X value.
• Output the interpolated values to Script Window, Result Log or a specified worksheet.

To use this tool, select Gadgets: Interpolate from the Origin menu, when a graph is active.

## Dialog Settings

This dialog can be opened from Gadgets: Interpolate in the Origin menu, or by selecting Preferences from the ROI fly-out menu.

 ROI Box X Scale Specify the X data range for the ROI. From The beginning X scale value. To The ending X scale value. Fixed (Prevent moving by ROI) Fix the X scale to prevent rescaling when moving the ROI box. Show Tool Name Specify whether to show the tool's name near the top of the ROI. Fill Color Specify the ROI fill color. Interpolation Line Color Specify the color of the interpolation line. Interpolation Line Width Specify the width of the interpolation line. Choose the quantities to be displayed at the top of the ROI box. Y at Left The Y value that corresponds to the left edge of the ROI. Y at Right The Y value that corresponds to the right edge of the ROI. Y at Specified X The Y value that corresponds to an X value which you specify in the X edit box. X This edit box is available only when the Y at Specified X check box is checked. Method Specifies the interpolation/extrapolation method. Options include: Linear Linear interpolation is a fast method of estimating a data point by constructing a line between two neighboring data points. Cubic Spline This method splits the input data into a given number of pieces, and fits each segment with a cubic polynomial. The second derivative of each cubic function is set equal to zero. With these boundary conditions met, an entire function can be constructed in a piece-wise manner. Cubic B-Spline This method also splits the input data into pieces. Each segment is fitted with discrete Bezier splines. Akima Spline This method is based on a piecewise function composed of a set of polynomials. The akima interpolation is stable to outliers. Please see the algorithm here. Number of Points Specify the number of interpolation/extrapolation points. Boundary Boundary condition is available when Method is Cubic Spline. Options include: Natural The 2nd derivatives are 0 on both ends. Not-A-Knot The 3rd derivatives are continuous on the second and last-second point. Smoothing Factor Available when Method is Cubic B-Spline. A non-negative parameter that specifies the smoothness of the interpolated curve in Cubic B-Spline interpolation. The factor helps user control the balance between smoothing and fidelity to the actual data. Larger values will result in smoother curves. Fit Limits To Specify the interpolation curve boundary. Interpolate to Rectangle Edge Interpolate to the ROI edges. If the ROI range is larger than the source data range, the interpolation will stop at the edge of the source data. Interpolate/Extrapolate to Rectangle Edge Interpolate/Extrapolate to the ROI edges, regardless of the source data range. Data Points Interpolate between the specified data points, which are enclosed by the ROI rectangle. Interpolate/Extrapolate to Full Axis Edge Interpolate/Extrapolate to the full X axis scale range in the input graph, regardless of the source data range. Custom Interpolate/Extrapolate to a customized data range, specified by the Left and Right value. Specify the output result worksheet.