Northern Eclipse Help Reference

 Circle Tool

This tool is used to outline a circle or ellipse on an image. The drawn ellipse can be used for measuring (see measure) objects within a created region, for selecting color threshold values for the selected region (see threshold), cropping the selected region of an image (see crop),  or cutting an area out of an image (see cut). To measure objects with this tool, threshold an image and then objects within the image can be outlined with this tool for measuring. It is also possible to create many ellipses on an image (and/or combine with other regions selection tools) before measurements are executed. (Regions may be removed by selecting Remove all selections or Remove last selection.)


All objects completely within the outlined ellipse, those touching the lines of the ellipse, or all objects that have a center of gravity within the ellipse can be measured depending on how the data options have been set (See Data Options).

Example: When the Circle Tool has been chosen, move the mouse cursor to the upper left quadrant of an image, hold down the left mouse button and pull an ellipse toward the lower right quadrant, encompassing the object (or objects) of interest. Release the mouse button and an ellipse will be in place on the image.


Threshold the image and then Measure. At this point, all of the selected objects in the field outlined by the ellipse will be measured and a Data Results dialog box will come up. In the Data Results menu, click on LOG to DDE to send the data to Excel or the currently connected program supporting Dynamic Data Exchange (see DDE).

This tool will make measurements (without thresholding) of all the regions placed on an image as long as in the Data Options section, under Object Policies, Objects Partially inside selection are set to Cut by selection.

Hint: If this function is used as a Visual Basic routine, Visual C++ routine or macro, the same size ellipse may be applied to new images repetitively as a mask (or template). Selected regions can be saved as regions (*.msk files) with the use of the Save current selections option.

See Also

Rectangle Tool
Trace Tool
Polygon Tool


Table of Contents
Function Reference
Menu Reference
Toolbar Reference