I perused the Meta and the site's help center and didn't see this topic addressed, so I hope it is not a duplicate.
This site occasionally sees questions of the form "Where can I find a data set for XYZ?" A recent example asks for face recognition databases. I have seen this same type of question posed on StackOverflow, and they generally get closed as off-topic because they are not really about programming. Is there any policy for or against this type of question on DSP.SE? Is it okay to request links to data sets to be used as training data, test data, etc.?
On the one hand, this seems like a great place to find answers to such a question, but on the other hand it doesn't seem to be in line with (my understanding of) the purpose of this site.
Signal Processing Stack Exchange is for practitioners of the art and science of signal, image and video processing.
Since there seems to be no clear definition of what is and is not considered on-topic, it is hard to justify either answer, especially since "practitioners of signal processing" can certainly benefit from having data sets available to them.