WlzPrinicipalAngle.c File Reference

Calculates the angle which the long principal axis makes with the given object. The functions are based on a combination of methods by Rees and Hibbard. (D.W.A. Rees, Mechanics of Solids and Structures). More...

Functions
double	WlzPrincipalAngle (WlzObject *srcObj, WlzDVertex2 cMass, int binObjFlag, WlzErrorNum *dstErrNum)
	Calculates the angle which the long principal axis makes with the x-axis in the given object. \[ \theta = \frac{1}{2} \arctan{(2 \frac{I_{xy}}{I_{yy}-I_{xx}})} \] where \[ I_{xx} = \sum_y \sum_x ((y - C_y) (y - C_y) G(x, y)) \] \[ I_{yy} = \sum_y \sum_x ((x - C_x) (x - C_x) G(x, y)) \] \[ I_{xy} = - \sum_y \sum_x (((x - C x) (y - C_y) G(x, y)) \] and \((C_x, C_y)\) are the coordinates of the centre of mass. More...

Detailed Description

Calculates the angle which the long principal axis makes with the given object. The functions are based on a combination of methods by Rees and Hibbard. (D.W.A. Rees, Mechanics of Solids and Structures).

Author

Elizabeth Guest, Bill Hill

Date

March 1999

Version

Id

08519d7aa941621dea5bbec5a42d6309d7ed4511

Address: MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, EH4 2XU, UK.

Copyright (C), [2012], The University Court of the University of Edinburgh, Old College, Edinburgh, UK.

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