# How do I implement an adaptive thresholding algorithm for underwater sonar

I want to implement an adaptive thresholding algorithm in MATLAB for filtering data received by an underwater sonar receiver. The data received has an interactive noise component resulting from underwater noise and specular reflection. CFARD method is close, but it does not serve my purpose. I have to image the data so that i am able to see the object, on a screen, that is placed underwater within the scandepth of the sonar. Any help will be greatly appreciated.

EDIT:

It is an underwater environment. I am trying to threshold a signal that has been received from a sonar transducer after it has been reflected by a solid target, that is situated in the same environment as the transducer. The problems belongs to Underwater Acoustic Imaging sonar domain. Problem is, I haven't been able to model the underwater environmental noise. From what I have read till now about this topic, the noise model follows a $K$-distribution. Also the environmental noise is not additive in nature, rather it's interactive. Hence the threshold has to be adaptive. I also mentioned CFARD method in my question. That is useful for signal processing in radar applications as we're just interested in finding a single point in a large area which has high energy. Same cannot be said about underwater acoustic imaging sonar, where we try to display the target on the screen as a video. I hope I have made it more clear now.

• Hello, while your question is interesting and on-topic for this site, we'd like more information from you. Can you describe your environment model, what is it that you're trying to threshold and how you've approached it so far? This site supports LaTeX, so you can enter math between two \$. Nov 24, 2011 at 16:35
• Well, what have you tried? This is basically a research project and your question basically wants us to model the environment and implement the algorithm for you... You still haven't addressed the points in my first comment. Dec 8, 2011 at 4:56
• You contrast your problem with the typical radar detection problem but I don't really know what you expect to see (i.e. what does the signal that you want to threshold look like? what are you trying to pluck out of it by thresholding?) A picture of some kind would help. Also, what do you mean by "interactive" noise? Multiplicative? Dec 8, 2011 at 13:30