These are Black Hmong hill tribe villagers harvesting rice in Sapa. As far as I vaguely understand, from the many times it was explained to me, the steps of rice harvesting are as follows:
1. Cut the rice (what you can see they're doing here in the picture).
2. Let it dry a little.
3. Thresh it (shake the rice from the stalk).
4. Lay the kernels of rice in the sun to dry for a few days.
5. Remove the outer shell from the rice (by tossing it in the air from a large basket repeatedly).
After that I think the rice undergoes further processing, but these are the steps I've witnessed personally. If anyone knows more about rice processing, please leave a comment. I'd be interested to know more, as so much of the planet depends on rice daily to keep hunger at bay.