Unclassified pixels are the result of the pixel not meeting the threshold criteria of the classifier 'rule' that is used. For SAM, the 'rule' is the spectral angle distance of the unknown pixel to the training class, in radians. If you use the SAM tool directly (not from the Classification wizard), you can set the threshold for the 'rule' for each training class to be more stringent, thus forcing more pixels to be 'unclassified'. Is this what you mean?

Hi,

I would like to create a class with unclassified pixels, because of the fact that when I use a specific spectral angle, SAM classifies pixels at a wrong category. So, I would like to know if there is a tool/way, in order to set a threshold and "tell" to the SAM that if the spectral angle is greater or lower than this value, classify it as an unclassified pixel. Thank you very much in advance!