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Makes the image into a window with the ring diameter and circle averaging tools. Analogous to the -> S Window button.
An image needs to be loaded before this menu can be used. As an example,
load the Au rings.tiff image
in the Demo_images / EDIF folder.
Then, invoke the ->R Window button. The image will be put into a special 'ring' window, and displayed:
The window title has 'Rings-' appended to the end (figure is out of date) to indicate that this is a 'ring' image, that is and image with the ring tools available in it. Later on, spots will be loaded into a 'spot image', which will have the spot tools, but will NOT have the ring tools. Images as displayed normally do not have either tool set.
Draws a new spot pattern in the center of the image. Adjustments are lost if window is already a ring window and you choose 'yes' in the warning dialog.
In this example, the image will look like this:
Due to the nature of this ring tool, it is not 'redrawn' with the window, in other words, if the window is covered and uncovered for any reason (such as temporarily switching to Netscape to read these instructions), the parts of the ring that were convered will not be redrawn. Sometimes the ring tool can disappear altogether. Use the Show tool to make it visible again.
Show | top
Redraws the ring pattern. If the ring image window is covered, and then uncovered, or if the lower right corner (the grow square) is clicked, for instance, the ring pattern will disappear. This menu redraws the pattern. If any part of the ring pattern is lost, it is best to erase the whole pattern by clicking on the Grow Box, and then inviking the Show Ring menu.
Adjusting the Ring pattern.
Adjust the ring pattern by moving the three small circles with the mouse. The central circle moves the whole pattern around the image: this circle should be placed as closely as possible to the beam center in the image. Usually the beam is obscured (as by the beam stop in the image above), but the pattern can be centered nicely by adjusting the ring diameter with either of the other two circles to almost match any of the rings in the image, and then moving the 'Ring Center' circle so that the movable ring lies just inside or just outside of the ring in the image.
The "Gap" circles are for adjusting the gap in the ring to correspond with the beam stop. The "Gap Position" circle will move the gap around the ring - the "Gap Angle" circle will follow along so that the size of the gap is not changed. When the "Gap angle" circle is moved, the "Position" circle stays fixed, so that the size of the gap can be changed. The image below shows the ring adjusted to measure the diameter of one of the outer rings:
It is sometimes difficult to tell if the 'match' is good, when the ring lies on top of the ring in the image. To check the match, just change the radius of the ring slightly so that the ring tool lies just beside (and concentric with) the ring in the image. Readjust the radius before any diameter measurements are made.
Here is a circular average , for this diffraction pattern. that is a plot of averaged intensity going around a circle vs. diameter of that circle. In the electron diffraction ring image, for example, if the ring tool is adjusted to match any of the rings in the pattern, the circle average will plot will have a distinct sharp peak for each ring. At this point in the example, with the ring tool centered on the image pattern, the circle average can be done. Note that the circle average does not use any information about the ring tool other than the center location - the position of the gap, and the radius of the ring are ignored.
The left of this plot is the center of the ring pattern. Clicking on
this plot window causes the radius in pixels, A and average intensity (pixel
values), B to be shown. Only the horizontal position of the mouse is used
for this. The values A and B are for the peak position,C, which was found
by holding the mouse down and sliding it along the plot, watching the values
at B for a maximum. If the center of the ring tool is not exactly on the
center of the diffraction pattern, the peaks in the above plot will broaden.
The radius for peak E, to be measured more accurately with the ring diameter
menu item, is 96 from this plot. The gap in the plot at D is caused by the
printouts for A and B. The plot can be redrawn, filling in this gap, by
clicking on the grow box. This will cause the blue numbers A,B to disappear.
The plot can be resized by moving the grow box. Ring
Diameter | top
For diffraction camera calibration. This tool will measure the radii, then the diameters every degree, plot them, and print the average diameter in pixels.