TransformJ: Matrix

General Description

This plugin enables one to create affine transformation matrices and files.

Dialog Description

An affine transformation is determined by a 4 x 4 matrix applied to input positions expressed in homogeneous coordinates [1,2] as follows:

Affine Transformation Equation

The 4 x 4 text field grid in the dialog represents the affine transformation matrix in the above equation. The default transformation matrix is the identity matrix (as depicted above). The last row of the matrix is predefined (the corresponding text fields in the dialog are disabled).

Rotate. Opens a dialog to specify a rotation angle (in degrees) and axis. After confirmation the specified rotation is added to the current matrix.

Scale. Opens a dialog to specify a scaling factor and axis. After confirmation the specified scaling is added to the current matrix.

Shear. Opens a dialog to specify a shearing factor, the shearing axis, and the driving axis. The latter is the axis as a function of which shearing is applied along the shearing axis. After confirmation the specified shearing is added to the current matrix.

Translate. Opens a dialog to specify a translation distance and axis. After confirmation the specified translation is added to the current matrix.

Invert. Replaces the current matrix by its inverse.

Reset. Replaces the current matrix by the identity matrix.

Copy. Places a copy of the current matrix on the system's clipboard.

Print. Outputs the current matrix to ImageJ's log window.

Undo. Replaces the current matrix by the matrix before the last change.

Load. Opens a file dialog and loads the selected matrix file after confirmation.

Save. Opens a file dialog and saves the current matrix to the specified file after confirmation.

Close. Closes the matrix dialog and returns control.

References

[1]	G. Wolberg. Digital Image Warping. IEEE Computer Society Press, Washington, DC, 1990.
[2]	J. Foley, A. van Dam, S. K. Feiner, J. F. Hughes. Computer Graphics: Principles and Practice. 2nd edition, Systems Programming Series, Addison-Wesley, Reading, MA, 1990.