ROI:Graph Panel
The Graph menu item under the View menu button calls up the ROI:Graph window. The ROI:Graph window is used to display various measures of curves and polygons and has the ability to create temporary point objects along curves for additional measurements in the statistics window. The functions in ROI:Graph are discussed below.
Graph
The black screen at the top of the ROI:Graph panel is the Graph. This is where various plots are displayed. Occasionally, some extraneous data is displayed on the graph. The user is advised to refresh the screen to eliminate this problem.
Height Slider
The height slider allows the user to zoom the graph in and out on the vertical axis. There is a bug associated with this function. When a graph is zoomed in and then back out, the graph screen sometimes turns white. To correct this the user should zoom back in (i.e., make height larger) until the graph turns black again. If not enough of the graph is visible on the screen at one time because of this, the user can increase the size of the entire ROI:Graph window to fit all of the data on the graph screen.
Width Slider
The width slider allow the user to zoom the graph in and out on the horizontal axis. This item has the same bug with zooming as the height slider described above.
Go Button
The go button causes ROI:Graph to execute the functions described in Subsections Graph Types and Measure on various regions. Once selected regions are changed, go must be hit to act on the new regions.
Measure Button
The measure button causes measurement data to appear on the ROI:Stats text editor. This data is generated based on what is selected in the graph types list item described in Subsection Graph Types and the measure list item described in Subsection Measure.
Slices Buttons
The slices: buttons allow the user to choose whether selected regions are examined from the current image or from all images.
- All Button
- The All button allows you to examine selected regions from all images.
- Current Button
- The Current button allows you to examine only the selected regions currently displayed in the ROI canvas
Graph Types Menu
The graph types menu has two options available with it. They are:
- Intensity
Choosing intensity from the graph types menu allows the user to view the average intensity inside a group of selected polygons on the graph. This option does not produce any measures available on the measure list item. Part of the graph may go off screen inadvertently. This is a bug.
- Intensity Cross Section
Choosing intensity cross from the graph types menu allows the user to view the intensity at every point along selected curves. This option causes several options to become available on the measure list item described below.
Measure Menu
The measure menu has three options -- measure point, measure line, generate point -- associated with it when intensity cross is chosen in the graph types menu. There are no options available in the measure menu when intensity is chosen in the graph types menu.
- Measure Point
Selecting measure point from the measure menu allows the user to display the intensity values at given points on the selected curves in the current image on the ROI:Stats text editor. This option generates a temporary point for this purpose. Executing measure point is done by pressing the left mouse button on the graph. This causes a vertical white line to appear on the graph. The user can then move the line to the desired location by dragging the mouse. When the mouse button is released, the selected statistics (title, slice number, etc.) are displayed in the ROI:Stats text editor for that location on the intensity curves. When the white line is being moved, white cross hatches move along the selected curves on the ROI main panel to indicate the location on the curve corresponding to the vertical line.
- Measure Line
Selecting measure line from the measure menu allows the user to display the length between two points on the selected curves in the current image on the ROI:Stats text editor. When measure line is selected, two vertical lines appear at either end of the graph. The user can then move these lines to the desired locations on the curves. When the lines are in place, left-clicking on the measure button causes the selected statistics (title, slice number, etc.) to be displayed in the ROI:Stats text editor. The linear distance statistic must be chosen to display distances in the text editor. Distances are not automatically displayed. As with measure point, white cross hatches appear along the selected curves to indicate where the vertical lines correspond to on the curves.
- Generate Point
Selecting generate point from the measure menu causes points to be generated at the desired locations on the selected curves in the current image. These points appear as (obj n) pk in the region list on the ROI:List window, where n is the object number (i.e., curve name) associated with the point and k is the kth point generated for that curve. For example, (obj 8) p3 is the 3rd generated point that is associated with obj 8. Generating points is done in the same way as measuring points is done and is described in Sub-subsection 1.) Measure Point.
Copyright 1994-99 Division of Physiologic Imaging, Dept. of Radiology, Univ. of Iowa
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