i want to diagnos the LED light in Picture.

If you are asking for permission to diagnose the image. i grant you the permission.

Your question is not clear you need to be more specific in your question so that others can help you. use the Improve Question link at the right bottom of your question to modify your question.

I agree that we should know were you stucked. If you ask generally for the solution, you would need some image processing algorithm. I am not sure how bright is the ambient but if the place of the led is the most brightest place then probably the luminance channel and some treshold value would be enough.