I have pictures of neurons that need further analysis but for that, I need first to remove all the background, leaving only the neuron. The only way that I get this, is manually (drawing the neuron and erasing) with ImageJ ( previously: adjust / threshold). But I have hundreds of pictures each experiment and I would like to find the way to do it automatically.

Please, see in attachment the original picture and the result that I need.

Thank you so much.