Automatic noise removing

[michaelaupaix]

Hello,
This is not really an issue, but more a wish or a question about a way to proceed.
I have to clean up some raster DTM.
Is there a way to automatically remove the isolated points, that are surrounded by a "no data" value ? See print-screen bellow, areas where the pixels are "alone"
Actually, I use the lasso tools to select the pixels, and assign it a no data value.
But maybe is there a way to automatically detect the isolated pixel (1 or 2 pixels for example), and to automatically assign
it the no data value ?
Thank you in advance for your answer, and thank you for the plugin !
Best regards