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 Bar.
This Rotate Image command opens from the
Image Window >Process >
Geometry menu and button
on the Main Toolbar. The "immediate"
form, shown first, opens when an image or image set is displayed in
the top-most window. The general form can be used to select source
images from folders, windows, or by matching templates.
Rotate Image Properties
Profile [|>]
Selects the parameter profile for this command and
allows you to save or work with existing presets.
[Select]
Opens the
Select Source Images dialog to choose images from an
image window, folder, files, name template, or a Mira 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
This group specifies how blank pixels are filled
with a value when the rotated image exposes blank pixels.
Target Value fills the
blank area with the specifiedValue.
Image Margin fills the
blank area with a value typical of pixels along the image
margin.
Value is the specific
value to set when the Target Value
option is selected.
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:
Center: Rotates the image about the
center position.
Cursor: Rotates the image using the
center of the
Image Cursor.
There are two ways to do a Cursor
Rotation:
Centroid checked: Rotates about the
centroid coordinate near the center of the
Image Cursor.
Centroid unchecked: Rotates about the
center of the
Image Cursor.
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. See these Examples.
Mira provides you 2 options for assigning a value
to the edge pixels:
Image Margin: Mira computes a value
typical of pixels around the margin of the image.
Value: Mira uses the pixel value you
specify in the Edge Value field. This can be an intensity value or
a color value. For example, 0 and 500.25 are intensity values, and
255,128,0 is a color value.
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.
button
on the 
Angle .. at
Centroid