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What Do Cats See?

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Re: What Do Cats See?

#41

Post by parfe »

Zikes wrote: post #26
chatman wrote: post #11

I have seen my cat find a mouse in a camouflaged garden even when the mouse was not moving. Either this study is wrong or my cat is special.

Their visual acuity isn't based on movement, like a Tyrannosaurus. If you look at a painting, you can still see it just fine even though it's not moving.

Michael Crichton invented T-Rex movement based vision for his books (attributed to contributions from frog DNA). The T-rex likely possesed incredibly powerful vision. http://en.wikipedia.org/wiki/Tyrannosaurus#Senses

Re: What Do Cats See?

#42

Post by carlesfe »

jobigoud wrote: post #13

I think there is one fundamental flaw with simulating color seen by non humans or dichromat humans. I've seen this in all computer based simulators. They simply change the weight of some colors relatively to others. But a dichromat with say, missing L cones will not simply mix green and red, he will experience "green" totally differently than a trichromat. What a trichromat call green is the result of the stimulation…

Oh, wow, thas was an incredible experience, thanks!

In trying to explain it some way... the green was SO GREEN that it actually looked like it was flashing blue.

By the way, is there any other similar experiment I could try?

Re: What Do Cats See?

#43

Post by Zikes »

parfe wrote: post #41
Zikes wrote: post #26

Earlier quoted context omitted.

Their visual acuity isn't based on movement, like a Tyrannosaurus. If you look at a painting, you can still see it just fine even though it's not moving.

Michael Crichton invented T-Rex movement based vision for his books (attributed to contributions from frog DNA). The T-rex likely possesed incredibly powerful vision. http://en.wikipedia.org/wiki/Tyrannosaurus#Senses

And their top speed is estimated at only 25mph rather than 45mph? My whole life is a lie!

Re: What Do Cats See?

#44

Post by SeanDav »

This seems to answer a question I asked myself just yesterday:

A neighbour's cat and my cat had a argument, no actual fighting - just lots of staring, yowling and that strange growling sound cats make. Nothing too questionable there, but then my cat did something rather strange - she started moving away by walking extremely slowly and I mean extremely slowly. I wondered what on earth she was up to but after reading this article I think it must have something to do with the fact that cats cannot seem to detect very slow motion. It appears that cats can move and position themselves in such a way that it may be undetectable (or nearly so) to another cat.

Of course there may be a completely different explanation, but I like this one.

Re: What Do Cats See?

#45

Post by arketyp »

carlesfe wrote: post #42
jobigoud wrote: post #13

I think there is one fundamental flaw with simulating color seen by non humans or dichromat humans. I've seen this in all computer based simulators. They simply change the weight of some colors relatively to others. But a dichromat with say, missing L cones will not simply mix green and red, he will experience "green" totally differently than a trichromat. What a trichromat call green is the result of the stimulation…

Oh, wow, thas was an incredible experience, thanks! In trying to explain it some way... the green was SO GREEN that it actually looked like it was flashing blue. By the way, is there any other similar experiment I could try?

You might be interested in what is called opponent process theory of color vision.

Re: What Do Cats See?

#46

Post by hnha »

jobigoud wrote: post #13

I think there is one fundamental flaw with simulating color seen by non humans or dichromat humans. I've seen this in all computer based simulators. They simply change the weight of some colors relatively to others. But a dichromat with say, missing L cones will not simply mix green and red, he will experience "green" totally differently than a trichromat. What a trichromat call green is the result of the stimulation…

that is very interesting, thank you! Could you link to some research/info or drop some terms so I can search myself?

Re: What Do Cats See?

#47

Post by joeyo »

ecopoesis wrote: post #33

Scientists at Berkeley have actually recorded what cats see by scanning a vision pathway in their brain: http://www.berkeley.edu/news/media/releases/99legacy/10-15-1... Here's a link to the video: http://www.youtube.com/watch?v=piyY-UtyDZw

What Garrett Stanley and Yang Dan did in that work [1] is very cool, but it's a reconstruction. It is "what a cat sees" in the same sense that a false color image is "what a satellite sees". Essentially they regressed the activity of an ensemble of LGN neurons (visually responding neurons in the thalamus) with pixels on a camera to build a set of linear filters in space and in time. Then they used those filters to reconstruct the scenes based on the neural activity alone [2]. So it's what the cat sees in a kind of information-theoretic sense.

1. https://stanley.gatech.edu/publications/stanley_dan_1999.pdf

2. And actually on a reread this morning, it doesn't seem that they cross-validated their reconstructions. So perhaps their reconstructed movie frames are actually an overestimation. Regardless, there is no doubt that their technique works and it was a great starting point. Keep in mind: they did this in 1999!

Re: What Do Cats See?

#48

Post by Aco- »

jobigoud wrote: post #13

I think there is one fundamental flaw with simulating color seen by non humans or dichromat humans. I've seen this in all computer based simulators. They simply change the weight of some colors relatively to others. But a dichromat with say, missing L cones will not simply mix green and red, he will experience "green" totally differently than a trichromat. What a trichromat call green is the result of the stimulation…

For the lazy programmers who don't want to write some quick JS to simulate what a dichromat perceives as green:

http://ill.cc/colorz.html

click on the page, toggle between red & green with any keypress

Re: What Do Cats See?

#49

Post by rxzv »

arketyp wrote: post #45
carlesfe wrote: post #42

Earlier quoted context omitted.

Oh, wow, thas was an incredible experience, thanks! In trying to explain it some way... the green was SO GREEN that it actually looked like it was flashing blue. By the way, is there any other similar experiment I could try?

You might be interested in what is called opponent process theory of color vision.

I know I can google it, but is there a particular link you recommend to read up on it?

Re: What Do Cats See?

#50

Post by earlz »

Aco- wrote: post #48
jobigoud wrote: post #13

I think there is one fundamental flaw with simulating color seen by non humans or dichromat humans. I've seen this in all computer based simulators. They simply change the weight of some colors relatively to others. But a dichromat with say, missing L cones will not simply mix green and red, he will experience "green" totally differently than a trichromat. What a trichromat call green is the result of the stimulation…

For the lazy programmers who don't want to write some quick JS to simulate what a dichromat perceives as green: http://ill.cc/colorz.html click on the page, toggle between red & green with any keypress

If you're on a mobile device without a keyboard, I made an alternative version that changes on click rather than keypress:

http://jsbin.com/iPIrucU/1

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