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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 12:11 pm
Wow, are people all pretending to be good students here? sweet, I don't remember you prepare so much for an exam when the forum was deserted.
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 12:14 pm
It's more motivating I guess ^^" Welcome back btw Very Happy Wanna join the study with us?
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 12:17 pm
Well, I would love to if I were in your class LOL But I'm done with exam (finally! mm16 ) gonna relax and play.
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 3:14 pm
Human Ear


  • 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.
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 9:07 pm
Auditory Pathway

  • 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.
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 9:16 pm
mm4 Am I the only one studying here?
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 9:21 pm
Nah you're not. We're in this together (although I warned you to not post a study realm)...
IT IS OUR COLLECTIVE FORCE THAT WILL DEFEAT THE HARDNESS OF THE EXAM~~~ mm1 mm1 mm1

Wait here, I'll give you my part of the cribsheet for echolocation mm18

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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 9:27 pm
sweet. wrote:mm4 Am I the only one studying here?
yes, trust me, the rabbit will not come back...
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 9:28 pm
NYA~~~ am a honest and reliable rabbit >_________<

I'll be back in a min~

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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 9:43 pm
ECHOLOCATION~

This is used in animals like bats. For a long time people thought bat's perceptual system was another mystery of the universe. People did experiment and found if we wax the ears of bat, they would screw up when they try to fly. It was not until 1930's that Donald Griffin used ultrasound measuring tools and found that bats emit all kinds of sounds, ranging between 12-200 kHz. Compared to human, we can only head up to 22 kHz.

Time delay in the echo can be used to measure the distance. The echo intensity is also a cue. This combo allow bat to solve various hearing problems by making two types of cries: constant and frequency modulated (CC and FM resp.).

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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 9:44 pm
mm14 the rabbit is motivated to study. How odd...
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 9:45 pm
evil-mashimaro wrote:
Wait here, I'll give you my part of the cribsheet for echolocation mm18

That's what you put in your cribsheet? And I already know this.
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:02 pm
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.

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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:04 pm
-______________-
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:05 pm
Spirit wrote:mm14 the rabbit is motivated to study. How odd...

So you thought that I was predictable? oohohohoho

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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:06 pm
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.

Why don't you run when CC is shorter? Isn't it a better strategy?
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:07 pm
Because there's a rabbit blocking the way.
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:13 pm
That's a good question, JellyFish. Because bat locate things using short CC while it detect things with long CC. If you run when CC is already short, bat will track you because it has already detected you. If you run during FM, then there's a chance that you'll get out of the bat's way because FM is for precision and it's a weaker signal. So if you suddenly RUN LIKE HELL, then you might save your life.

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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:14 pm
It's more like RUN TO HELL.
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:15 pm
You shouldn't overlook sweet.'s speed meheheh

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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:16 pm
Why use me? Sad
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:17 pm
Because you are sweet and the bat loves it Smile

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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:17 pm
Who's the bat?
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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 10:18 pm
It's the one who hasn't come yet. We are still waiting for his CC... you know? mehehe

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Re: Computational Perception [study realm]

on Sun Apr 23, 2017 11:59 pm
-______-

So what are the similarities between the eye and the ear?
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Re: Computational Perception [study realm]

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