Appion

fixed with r14139. A factor of two error.

Test:
1. Use any image good for ace2 run.
2. View its fft image in the viewer and click on the image to see the pop-up map.
3. Use the ruler to choose the low frequency set point at an obvious point such as at half radius of the ctf first node.
4. Choos the high frequency set point at the first ctf node.
5. Use these values and run an ace2 run.
4. Observe the resulting graph. The normalized power spectrum should be roughly flat below half ctf first node frequency and leave the first node behaving similarly to what is expected without the filter.

Reviewed and tested. Thanks Anchi!