IDP3 Region of Interest

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The ROI window allows a subsection of the work area to be examined in greater detail. The ROI rectangle is fixed to the main screen and the images may move around under it. The data in the ROI is updated whenever the data is redisplayed. The initial zoom factor of the ROI can be set in the user preferences file.


Auto Region and Auto Zoom

If you know that the size of the ROI you want to work with will be the same every time, you can set the size of the box in both the idp3_preferences file and in the File/Edit Preferences from the Main Display Window. If you left click on the image in the Main Display Window, a ROI of the given size will be formed, centered around where you clicked. You can also adjust the size of the ROI using the Adjust Coordinates feature in the Adjust ROI Menu.

When a ROI is created, the default zoom is 1. This can be changed in the idp3_preferences file with the "roi_default_zoom_factor" preference.

Region of Disinterest

When using the ROI window, a ROD mask may be created using the 'annotate' widget. Regions of the ROI that are masked are displayed as blank areas and are referred to as the 'Region of Disinterest'. The ROI window provides tools for saving, reading, and moving these RODs. When the "Define ROD" menu item is pressed, the annotate widget pops up and the user may draw circles, lines, rectangles, and ellipses on the ROI window to define the mask. Remember that each shape must be saved before the next shape can be drawn. Also, remember that each shape must be filled, not just outlined before it is saved. When the mask is finished, the user must save a bitmap in TIFF format using the default name, "annotate.tif", before exiting the annotate widget. This is accomplished by pulling down from the 'file' menu in the annotate widget and selecting 'export bitmap -> TIF'. When the "Please Select a File for Writing" window comes up, just press "OK". Then the user can exit the annotate widget "File -> Exit" and the ROD will be displayed on the ROI window.

NOTE: Polygons and binary masks are preferable to using the ROD.

Masks in the ROI

Binary masks where the value of a good pixel is set by the value of mask_good_value in the preferences file may be read as fits, hdf, or tiff files for use in the roi. Masked pixels are excluded when computing radial profiles, noise profiles, and polygon statistics.

Mouse Buttons

Activities with the mouse buttons are controlled by the mouse mode selection made at the top of the roi widget. There is no distinction between which mouse button was used.

An important note about cursor readback:

Cursor readback is available in the ROI window. Cursor position is shown in main window pixels. It is very important to remember that FRACTIONAL POSITIONS ARE GIVEN TO THE RESOLUTION OF THE ROI ZOOM! That is, if the ROI zoom is 4, the cursor position is reported to the nearest 1/4 pixel. Therefore, positions of image features MAY BE REPORTED SLIGHTLY DIFFERENTLY AT DIFFERENT ROI ZOOM FACTORS! The user should experiment with this to convince himself or herself that he or she understands how this works before attempting to locate object positions to fractional pixels.


File Menu
Adjust ROI Menu
Zoom Menu

See note on Other Info page about Interpolation Methods.


Align Menu
Mask Menu
Plot Menu
Stats Menu
  • Set Color Menu

    Allows user to set the desired color for each of the ROI graphics: radial profile circle, inner and outer noise profile circles, cross section lines, and polygons.


    Select Mouse Mode

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