In the Target Detection Wizard in ENVI, you can choose to output your results to ROIs. You could then convert the ROIs to a classification image, using ENVI's Classification Image from ROIs tool. Then you could calculate ROC using the resulting classification image. Peg Exelis VIS

Thanks Peg. It was very useful information for me. I could successfully make class image from sam results. but when I tried plotting it, it neeed ground truth information in either of two forms, image or roi. I have one hyperspectral input image , in which I visibly can see my targets. so how can I generate truth image from it. or when trying to mark roi in it, I was unsure that my selection with mouse clicking will be good enough for accuracy assessment. I mean selecting for sample is fine but considering it as ground truth might result in wrong results. please suggest what can be done to solve this situation. Thanks.

It sounds like you are on the right track. If you don't have ground truth in the form of an image or ROIs, then you cannot use ENVI's ROC tool. I know it can be difficult to accurately specify ROIs over small targets that you know are correct. But that is what you will need to do. If you cannot do it accurately enough to consider it to be "ground truth" then the ROC tool will not really be helpful for you. - Peg Exelis VIS