Image Cursor

Image Cursors

The Image Cursor is a permanent tracking cursor available in every Image Window. The Image Cursor is used for locating centroid positions, measuring region statistics, and defining the limits of column and row profile plots. The Image Cursor is different from the mouse pointer that roams around the screen, as shown below:

The image cursor is dedicated to its image window and it stays fixed on the image unless you intentionally move it. It can be adjusted to any size and positioned anywhere within the image. See Adjusting the Image Cursor.

The Image Cursor can be switched between 3 different shapes or hidden from view. You can select the shape using the Image Cursor Properties dialogs or by using the (Cursor Mode) button on the Image Bar, as shown in the picture at left.

There is only one Image Cursor per Image Window. Therefore, if an image set is opened by the window, the same Image Cursor is used for all members of the set. For example, if you use the Image Cursor to define the region to be cropped, and the Process Image Set flag is enabled, then all members of the image set will be cropped to the same region marked by the Image Cursor.

Numerous keystroke commands make measurements, create plots, and perform other operations in concert with the Image Cursor. See Image Tool Keystroke Commands.

The Image cursor position and edges are defined in terms of image pixel coordinates. Therefore, if you magnify the image, the Image Cursor coordinates remain correct at the level of sub pixel precision, independent of the way the image is displayed.

The values of pixels centered around the image cursor can be viewed using the Pixel Table Pane. The pixel table updates as the image cursor is moved.

The bounds and size of the image cursor are displayed for the current image using Status Bar space along the bottom border of the main Mira window frame, as shown below. These quantities are dynamically updated as you move or resize the cursor. The reason this information is displayed on the main window frame, rather than the Image Window frame itself, is so that it remains visible when the bottom image window frame is hidden or displayed outside the current Mira area.

Mouse Pointer vs. Image Cursor

The table below lists the differences between the capabilities of the Image Cursor and the Mouse Pointer.

Property	Mouse Pointer	Image Cursor
Tracking & Moving	Always moves with the mouse.	Moves only in Cursor Mode and when the mouse button is is down. Otherwise, remains where you drop it.
Size	Cannot be resized.	Resized by dragging the edges or by setting exact dimensions.
Dimensions	Fixed by icon size.	Measured in image pixel units (i.e., columns x rows).
Coordinates	Dynamically displays image x, y, column, row, and pixel value as it roams over the image.	Does not display coordinates. Measurements such as Centroid are listed in a Report Window or Measurement Pane.
Shape	Takes the shape of an icon for each different command or tool mode.	Can be changed to crosshair, rectangle, lines, or hidden. The rectangle also shows a central crosshair.
Position	Moved only by moving the mouse.	Moves using the mouse in Cursor Mode or using the keyboard arrow keys.

Mouse Pointer vs. Image Cursor

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