Hello, I am currently doing a project pertaining to alerting people that a police, ambulance, or firetruck is incoming through a visual screen. This is particularly for people who are hard of hearing and deaf. To do that, I was going to compare the recorded noise to a saved file that has a similar noise. For example, I compare the recorded noise of a police car and the noise of a saved file of a police car to create a condition to determine if the sounds are similar/congruent or if the sounds are not alike. If they are congruent, then the VI shows an indication to announce that an emergency car vehicle is coming by showing a message that can reset the loop by pressing the OK button (although I may change this). The problem is that I am trying to compare the saved sound file with the recorded sound file to create the previously stated condition. I have tried a few nodes and VI's to do this but I had no luck. I heard that you can square the data of the different sounds to compare them in energy form (or something like that) but I do not know how to do that. Also, take note that the way I set up the condition may be wrong on the part that has the Display to user VI but clarification on how to tweak that would be helpful. I attached the VI so you can hopefully point out any errors and give suggestions. Thanks for any time and effort.
If I were doing this project, my first try would be to take a Fourier Transform of recorded sound and the received sound. Get the magnitude of the Fourier Transform of each, normalize them, and perform a correlation on the two. Normalizing them will help with differences in intensity between the pre-recorded and the new signal. Going into the frequency domain will help with differences in pitch (i.e. Doppler Effect).
There are many different kinds of sirens and the sounds they make have different time domain and frequency domain representations. To start I suggest that you select just one siren type and work on that . If you succeed with that, then try to generalize to other types.
One common type of electronic siren uses a frequency modulated square wave.The frequency ranges from several hundred hertz to 2-3 kHz. The mode called "Wail" on some sirens modulates that frequency in an approximately sinusoidal manner over a period of several seconds. Because this sound is easily simulated, I suggest that it might be a good starting place.
Have a look at the spectrograms
Downsizing a a spectrogram (peak area) to 8x16 bit and find the best match?
Thanks for the suggestions, I will try to use this info to hopefully make production. I will update on my progress if I run into another problem.