autotrace FRET lifetime less than 5 frames

[dsterry]

Problem: autotrace's "FRET Lifetime" criteria is defined as the number of frames with FRET efficiency above a threshold in groups of at least five frames. This approach was taken to avoid the contribution of spurious 1-frame events to the total FRET lifetime. However, this behavior can be confusing to users who notice that 1 frame gives the same result as 5 frames. There is a tooltip on the control describing this, but users are likely to miss it.

Workaround:

1. Use the criteria "maximum FRET value" to define a threshold for detecting single-frame events.
2. In cascadeConstants.m, set rle_min=1, which will disable the feature.

Development ideas:

• In autotrace, don't allow user to set a FRET lifetime criteria value less than rle_min.
• In autotrace, allow user to adjust rle_min or disable the feature.