Computational Perception [study realm]

• Head Related Impulse Response (HRIR) at different angles around the head (azimuth and elevation)
  
• The head related transfer function applies a FFT to incoming sound.
  
• The pinnal notch allows us to distinguish the elevation angle.
  
• Inside the ear, the ossicles transfers frequency from ear drum to fluid in cochlea.
  
• The pressurized fluid will bend the basilar membrane.
  
• Signal is transmitted to cochlea nerve, ganglion cells spike at peak of the basilar membrane deviation.
  

• The pathway is cochlea → cochlear nucleus → (lateral and medial) superior olive → … → auditory cortex (A1 with spectro-temporal receptive fields).
  
• Sound from the left ear and right ear split into low and high frequencies at cochlear nucleus and merge at the superior olives.
  
• Duplex theory of binaural hearing (Rayleigh, 1907): interaural level different (ILD) is computed for high frequencies while interaural timing difference (IDT) is computed for low frequencies.
  
• The first is modelled as addition of excitatory input from the same side and inhibitory from the other side at the LSO.
  
• The second is modelled as addition of excitatory input from both side at the MSO.
  
• But a better theory for the second one is Jeffress's model in 1948: coincidence detectors in MSO which suggests a temporal precision of 0.01 ms.
  

sweet. wrote: Am I the only one studying here?

evil-mashimaro wrote:
Wait here, I'll give you my part of the cribsheet for echolocation

Spirit wrote: the rabbit is motivated to study. How odd...

evil-mashimaro wrote:People love bat, but they better not disregard the knowledge in this cribsheet~
Bats love to eat moth. Even more when they are larger than around 170 kHz which is around 2 mm. Because bats can pinpoint their location using their ultrasound.

Just imagine a moth named sweet. flying in the dark gloomy night; I bet you never find this information in an academic textbook. Many sound may be around but you are aware of one sound that has the potential to change the fate of your life as a moth. That sound may start as CCs. Long and ugly. You're still safe if you hear CCs because that means a bat is far away. If the bat is near, then it must be stupid because at a close distance the long cry will overlap with the echo. Otherwise the bat is just not interested in you. Then if the CCs is getting faster, maybe you should think of changing your direction. Then if the CCs shift to FM... RUN LIKE HELL because you'll have no time to think before you get devoured.

Or maybe if you are a moth, then you don't think, nor run, you just fly...
I bet you don't find this information in a textbook.