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# ellipfit, circfit

Fitting a circle or an ellipse on 2D given points
Details
Version
2.0
Author
Samuel Gougeon
Maintainer
Samuel Gougeon
Categories
Supported Scilab Version
Creation Date
May 12, 2015
Description
```
Runs on all platforms: Windows, Linux, Mac OS

-->ellipfit

function [Xc, Yc, a, b, g] = ellipfit(Xp, Yp, Po)
ellipfit: Looks for the best circle or ellipse fitting some given 2D data
points

CALLING SEQUENCES:
ellipfit             // Displays this help
ellipfit circle      // Runs a randomized circle-fitting demo.
ellipfit ellipse     // Runs a randomized ellipse-fitting demo.

[xc, yc, r]       = ellipfit(Xp, Yp [,Po]) // fits data with a circle
[xc, yc, a, b]    = ellipfit(Xp, Yp [,Po]) // fits data with a right ellipse
[xc, yc, a, b, g] = ellipfit(Xp, Yp [,Po]) // fits data with a tilted ellipse

PARAMETERS:
Xp: Row or column of abscissae of data points
Yp: Row or column or ordinates of data points (same length than Xp)
xc, yc: Coordinates of the center of the best fitting circle | ellipse
r: Radius of the best fitting circle
a: Horizontal radius of the best fitting ellipse
b: Vertical radius of the best fitting ellipse
g: Tilt angle, on [0, 90]°
Po: Optional explicit vector of initial parameters (best guess).
It may have from 1 to 5 elements, in this order:
[xc0 yc0 r0]  or  [xc0 yc0 a0 b0 g0]
The number of expected output parameters chooses the fitting type.

CHANGES 1.0 => 2.0
------------------
- Tilted ellipses can now be fitted.
- The type of fitting is now set by the number of expected output parameters.
- Initial parameters: Automatic first guess improved a lot.
- Constrains on parameters added (automatic guess).
- Demo improved and updated
```
Files (2)
[8.57 kB]
Miscellaneous file
```ellipfit() macro. Randomized demos are included (see the description hereabove)

* MAKE IT AVAILABLE in EVERY SESSION: Click here to see HOW TO

* Get help: Enter "ellipfit" without parameters

```
[10.44 kB]
Screenshot
```Small screenshot for thumb (from the demo)
```
News (0)