Transform

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For the MIPAV HTML help, please use [1]

Introduction

The Transform/Resample dialog box is a user interface for transforming and (or) resampling images. It offers multiple options that help a user to, first, define the transformation matrix, and then execute the transformation and (or) resampling. The interpolation method can also be specified in the dialog box. The following interpolation techniques are implemented: Nearest-Neighbor, Bilinear, Trilinear, 3rd order B-spline, 4th order B-spline, Cubic Lagrangian, Quintic Lagrangian, Heptic Lagrangian, or Windowed sinc.

To learn more about interpolation techniques used in the method, refer to Interpolation methods used in MIPAV.

Background

The dialog box has two tabs - Transform and Resample. The Transform tab allows the user to set up the transformation matrix and choose the interpolation method. The Resample tab is designed to set up the resampling interpolation.

Transformation matrix

The Transform tab of the dialog box allows the user to transform an image using the transformation matrix that can be either

• A matrix associated with the image,
• A matrix stored in a separate file,
• The user defined matrix, defined in this dialog box.

The Transform tab options

Transform

No transformation - if selected, this option disables all transformation options, but the interpolation options are still available. Therefore, the user can not perform the transformation, but is still able to run the interpolation for a chosen image.

Use image's associated matrix - if checked, this option allows using a transformation matrix associated with the image. See Figure 1.

Read matrix from file - if checked, reads the transformation matrix from a file. The user should select the file where the transformation matrix is stored.

Use defined transformation matrix - if checked, makes available the transformation text boxes, which are used to design the user defined transformation matrix. In these boxes, the user can enter values for translation, rotation, scale, and skew. Refer to Figure 2.