Rotate Image


The Rotate Image command can rotate an image or image set in 90 degree steps, perform mirror flips, transpose about the main diagonal, and apply free rotation using any precise angle. You also can rotate an image by an angle using the button on the Image Toolbar.

Properties of the Rotate Image Command

Profile

Selects the parameter profile for this command.

[Select]

Selects the source images from an image window, folder, files, pattern, or a file list.

Angle .. at

The rotation angle, measured in degrees.

 

When Angle is selected, this parameter specifies the center of rotation. You can choose either the center of the image or the centroid coordinate near the center of the image cursor (see section below)

 Rotate 90

Check this box to rotate 90 degrees in the positive sense.

 Rotate 180

Check this box to rotate 180 degrees.

 Rotate 270

Check this box to rotate 270 degrees in the positive sense.

 Reverse

Check this box to mirror flip the image in a left/right sense.

 Flip

Check this box to mirror flip the image in an up/down sense.

 Transpose

Check this box to flip the image about its main diagonal, which extends from pixel [1,1] to the opposite corner.

 Centroid

If selecting the Image Cursor option, check this box to have the center of rotation at a centroid position near the center of the cursor. For example, you may want the image rotated about the center of a star.

Edge Replacement

Defines the method used to evaluate "blank" pixels when the rotation brings non-existing data into the output image.

The options Value and Image Margin are described in the section below.

Value

The value to assign values to the edge pixels when Edge Replacement = Value.

 Resize Image

Check this box to allow the image to be enlarged to hold all pixels after rotation. If this box is not checked, the image size remains the same and the corner pixels rotate outside the visible image.

Choosing the Rotation Point

The image is rotated about a point that can be selected from the following options:

There are two ways to do a Cursor Rotation:

If using the image cursor be sure to position it before opening the menu containing this command.

Edge Replacement

The "edge" refers to the blank pixels that rotate into the output image from off the edge of the original image. These pixels have no value but some values must be assigned to them in the rotated image. Examples.

Mira provides you 2 options for assigning a value to the edge pixels:

Using the Transpose Operation

The Transpose operation reflects pixels across the main diagonal of the image matrix. FITS image have their main diagonal running from the lower left toward the upper right. Other graphics formats have their main diagonal running from upper left to lower right.

Related Topics

Geometry Commands, Register Images