Axtell's Notes: June 9

Another not as productive day as I would have liked. The main discovery of the day is that I was giving the doFFT() method the wrong length of array. The array length should be a "buffer" that is always a power of two. The higher the power, the more accurate the result. I had been giving it a list as long as there were samples (Often in the hundred thousands for a sound clip of several seconds). It is now set to 8192 (2^13) and seems to be working better. It is displaying a much nicer image, but still has the mirroring effect. Should figure out how to fix that.

I did some basic clean-up of my classes so the code would only have to work as hard as it had to. I also found a new way of converting bytes to floats. Instead of the confusing method I had (borrowed from JASS) I found four lines in Sonogram's code that accomplished the same thing. It casts the bytes as Bytes, and the Byte class has a method floatValue().

The window that pops up with the FFT is neater now. The line graph now is scaled as the window is re-sized so that it always fills the x- and y-axises. Other enhancements to be added to the graph window at a later date include:
-If more than one window is opened, offset each additional window so all are visible
-One window should close without closing all windows and ending the program
-The compare option will print in the same window in a different color for each window

Windowing functions are still not working correctly. Bartlett and Hamming windows seem not to make any change on the FFT. The Hanning window still produces nothing. A little research into this showed that this is because the method returns all zeros. I tried replacing the equation with several other versions of the Hanning window I found, but they all returned zeros. Because of this, I decided that I must be implementing the window in my code incorrectly. Once again, windows are on the to do list tomorrow.

On the topics of windows, I discovered that the Hanning window is more accurately called the "Hann window" in honor of van Hann. Because of the existence of the Hamming window and the ensuing confusion it tends to be called "Hanning" nowadays.

Tomorrow's Goals:
-Get windows working
-Figure out why the function mirrors itself and fix
-Print the corresponding frequency's along the x-axis
-Continue to update the graph window