Isis3: Qview Statistics Tool Error

[lwellerastro]

ISIS version(s) affected: 4.4.0 (also seen in isis5.0.0-RC1)

Description
While clicking in low dn areas x-number of times, the following error message appears:

It's nearly always the same line of code (212 for isis4.4.0 and 196 for isis5.0.0), but the bin range start value will vary depending where in the image you are clicking (based on dn's).

How to reproduce
See /work/users/lweller/Isis3Tests/Qview/StatisticsTool/TC1W2B0_01_01207S888E3572.lev1.cub

• Open Statistics tool,
• uncheck Hide Display (or not, doesn't matter but nice to see things),
• set Box Samples=Box Lines=9 (or 11, 13 anything really),
• and click in a shadowed area having very low dn's (<1), Error will eventually appear.

There doesn't seem to be any pattern to how many clicks before it pops up - sometimes a couple, other times many more. Does not seem to be a problem in areas where dn's >> 1. Though it seems if I click in high dn areas then go to low dn's, I can't get the message to reappear. But if I close the Statistics display window, reopen and go to a low dn area, it doesn't take too long for it to reappear.

[acpaquette]

@lwellerastro I will have some time this week since I am on a release sprint and the release will likely be out tomorrow to go over this. I have been able to reproduce the error but it seems like it manifests when transitioning from dns > 1 to dns < 1. I would like to narrow this down further to provide context to anyone that decides to tackles this ticket.

[jessemapel]

This is likely caused by the Histogram changes. Previously Histograms with a single value in them would "bound" that value. Now Histograms with a single value error. Changing the StatisticsTool to use an ImageHistogram will likely fix this.

[acpaquette]

Unfortunately this is not the error. ImageHistogram and Histogram differ in how the bins are structured and how the percentiles work.

The error is happening when the Histogram object is being constructed before it is even populated with any data. Here is the line that errors: ImageHistogram hist(p_stats.BestMinimum(), p_stats.BestMaximum());

In looking into this the p_stats.Best[Max/Min]imum() is likely failing to some degree.