i want neural network give me output as like 'unknown clas' for all untrained images. How can i do this ???

sir, now i attached my code please check it.

[Walter Roberson]

This appears to be the same question as http://www.mathworks.co.uk/matlabcentral/answers/125878-how-to-define-unknown-class-in-neural-network so you should attach your code there and delete this question.