The free-form region of interest tool defines a geometric area that cannot be enclosed using the other ROI tools.
Click on the free-form
ROI button, .
Move the cursor to a starting point on the image and click the left mouse button.
While holding down the left mouse button, drag the mouse to define the region. When you release the mouse button, the viewer automatically closes the region by connecting the end point with the start point. The viewer calculates the area within the defined space and displays it on the image.
To correct the region outline, move the mouse until it crosses over the point to want to move. The cursor changes to either a two-directional or four-directional arrow.
Click the left mouse button and drag the mouse to move the line. If you hold the Shift key while dragging, the line will move in an arc. Without the Shift key, you will just move the point under the cursor.
Release the mouse button. The viewer recalculates the area inside the region.
If the image object does not contain pixel size and spacing information, measurements are displayed in pixels. To convert pixels to real-world dimensions, you must calibrate the image.