DIVA - USER MANUAL

[ Home | User Manual | Design | IDL | Links ]


Back | Contents | Next

Regions of Interest (ROI) - extraction and analysis

1. ROI Extraction

There are 3 main methods of ROI extraction;

In each case this is achieved by a left-click followed by dragging the cursor over the image to the desired position. A rubber-band box will be displayed.

An ROI extraction mode may be activated by selecting an entry from the ROI menu droplist located on the main menu bar. The currently selected mode is indicated in the information bar as "Function:"

The selected ROI will be displayed in a GUI.

2. Area ROI

There are 3 area ROI modes;

rectangular Using the mouse, left-click on the image at the desired location and drag it to some other position and release. This area ROI is defined by the initial and final coordinates.
irregular Use a series of left-click and release events to define a series of points on the image. To close the ROI use a middle-click. Up to 100 points may be defined.
circular Define a circular ROI with an initial left-click and then drag out the radius.

An AREA ROI GUI will appear after a ROI is defined. It has an information bar at the bottom, displaying cursor position and the value of that pixel. Other functions, accessed by buttons, include zooming, displaying a surface representation, calculating statistics, printing and displaying the line-averaged profiles of either columns or rows.

3. Zoom ROI

Left-click a point on the image to activate a GUI displaying a zoomed image of the selected area (x2 by default - this may be changed in the GUI itself). The (rubberband) zoom-box is moveable (left-click and drag) and the zoomed ROI will update.

A ZOOM ROI GUI will appear after a ROI is defined.

4. Line ROI

There are 4 line ROI (profile) modes;

horizontal/vertical only It is often convenient that a straight line profile, either horizontal or vertical, be investigated, since these represent a row or column of pixels. Hence in this mode, only a straight line is allowed. To use, left-click on the image, drag the rubber-band line to the desired end point and release. This applies to both horizontal and vertical line profiles, and which one is selected depends on which axis length is the greater.
all column Right-click on the image to produce a line profile of all pixel values in that column.
all row Right-click on the image to produce a line profile of all pixel values in that row.
any Right-click, drag and release to extract a line profile between any two points on the image.

A LINE ROI GUI will appear after a ROI is defined.

Back | Contents | Next


[ Home | User Manual | Design | IDL | Links ]

E-mail me at j.a.rainnie@rl.ac.uk

Copyright © 2003 John Rainnie
Last updated January 2003