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Edge detection doesn’t explain line drawing

aaronhertzmann.com

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Re: Edge detection doesn’t explain line drawing

#71

Post by jdietrich »

cnity wrote: post #3

As someone (probably like many here) who graduated from a university which taught computer vision and peripheral neuroscience courses, with such titles as "Computational Neuroscience of Vision", I always felt that trying to understand the human brain as a kind of algorithm was a bit of an artefact of computer scientists as they approach biology. The truth is the visual cortex is vast, and not sufficient to explain th…

>trying to understand the human brain as a kind of algorithm was a bit of an artefact of computer scientists as they approach biology

I think the advances in neural networks over the past few years have shown that the failure of such an approach was mostly a matter of scale. Trying to reduce the visual system into a few kilobytes of code is of course a fool's errand, but trying to emulate it with ~10^11 parameters is looking much less foolish.

"The brain is a computer" is a stupid analogy if you think of a computer as a scalar or vector machine, but it's much less stupid if you're thinking in tensors.

Re: Edge detection doesn’t explain line drawing

#72

Post by lostlogin »

pavlov wrote: post #68
detourdog wrote: post #60

Earlier quoted context omitted.

I first heard Turtles all the way down in spoken story by Kurt Vonnegut. Does anyone else have a source of the story or is that the source?

“The world is on a turtle’s back” is Iroquois cosmology, at least.

Wow, thank you. I’d always thought this a Pratchett things.

I see it has a history in India and China too.

https://en.m.wikipedia.org/wiki/World_Turtle

Re: Edge detection doesn’t explain line drawing

#73

Post by CamperBob2 »

simias wrote: post #9

Ten years or so ago I was working on a video chip that had an upscaler feature. While prototyping and simulating it, we first started by applying a mathematically-correct (i.e. information preserving) FIR filter to do the upscale. Then we compared the result with other solutions and found that ours looked worse. We asked our colleagues to blind-test it and they all picked third-party-scaled images over ours. At first…

It's like playing a familiar song on an old cassette tape on a modern system. The user will likely be tempted to crank up the treble, trying to recover content that isn't there. In the image-scaling example, the HF content wasn't there to begin with -- since you upsampled it, it couldn't have been! -- but there's a strong psychological expectation for it to be there.

With images, it's a bit easier to put the high frequencies back in via judicious use of edge enhancement, perhaps because you have two dimensions to work with rather than one dimension in the audio case.

Re: Edge detection doesn’t explain line drawing

#74

Post by AndrewKemendo »

>Yet Lines-As-Edge supposes that the vision system discards all of this other information present in an image, for just this one special case. Why?

The "other information" is not discarded, it's just not processed yet

I think this is a misrepresentation of how the visual system works and views the vision system as more "batch" than the continuous process it is.

So if you think about it as a time series problem, when light hits the retina then "inference and processing" starts with a kind of "fast and rough" inference and then proceeds to fill in details and contextual coherency follows

I'd have to go pull out the textbooks but if you look at visual interpretation sequence it's something like:

Movement > edges > color > details

So your visual system acting as an object detector - from sensor to inference - makes inferences about movement first, then infers the edges, then infers color and finally additional details in the last few ms

Nothing is "discarded" it's just less relevant in the first pass and additional refinements happen mostly sequentially - this all happens in nearly imperceptible time.

Re: Edge detection doesn’t explain line drawing

#75

Post by olaulaja »

simias wrote: post #9

Ten years or so ago I was working on a video chip that had an upscaler feature. While prototyping and simulating it, we first started by applying a mathematically-correct (i.e. information preserving) FIR filter to do the upscale. Then we compared the result with other solutions and found that ours looked worse. We asked our colleagues to blind-test it and they all picked third-party-scaled images over ours. At first…

Sounds like using the wrong metric, the upscaled image should be compared against the original full resolution one, not the downscaled one. Obviously you can't know what the full resolution one looks like when actually upscaling (vs testing), but you can make an educated guess.

Re: Edge detection doesn’t explain line drawing

#76

Post by adolph »

HPsquared wrote: post #33
adolph wrote: post #21

Earlier quoted context omitted.

I think in the case of “to lose one’s temper”, there isn’t an obvious match between the technology of the day and the early medical theory of four humours, not of metal-working. Origin of Temper, New Oxford American Dictionary: Old English temprian 'bring something into the required condition by mixing it with something else', from Latin temperare 'mingle, restrain'. Sense development was probably influenced by Old F…

So tempered steel is well-balanced steel, or mild-mannered. See also the well-tempered clavier. In music, the temperament is an aspect of the tuning system relating to how the dissonances of different notes are balanced.

How did WTC not come to my mind, it is one of my favorite works! Maybe because it drives my spouse up the wall so I only listen it less often than I’d like. My favorite recording is the Ishikawa from OpenGoldberg [0].

Reflecting on my response to “lose one’s temper” I can see how a straight line reading of etymology (as I proposed) might be misleading if the specific idiom did come or return from steel or string as an enhancement/extension to the original’s meaning.

https://youtu.be/nPHIZw7HZq4

Re: Edge detection doesn’t explain line drawing

#77

Post by raverbashing »

dylan604 wrote: post #55
hprotagonist wrote: post #8

Earlier quoted context omitted.

ah, someone who paid attention in lecture! (incidentally; there’s a fairly deep literature of historians of science that have carefully documented that we describe ourselves as analogous to the most sophisticated technology of the day: see “to lose one’s temper”, “to blow a gasket”, “i got my wires crossed”, “sorry, cache miss”, … as metaphors and idioms of mental state through the centuries that reflect the cool tec…

>as metaphors and idioms of mental state through the centuries after listing a bunch of things from the previous century that barely stretches a bit further back. i would have been impressed if you had come up with a phrase from medieval tech, or roman/greek/egyptian. hell, i'd settle for pioneer days tech to allow for "centuries". otherwise, it just feels like modern day analogies.

It's possible a lot of those are not even seen anymore as such because the use has become commonplace and the original meaning was lost to time

Re: Edge detection doesn’t explain line drawing

#78

Post by mjburgess »

lostlogin wrote: post #70
mjburgess wrote: post #42

Earlier quoted context omitted.

Reasoning by analogy is one of the ways we solve the framing problem. So, when explaining the universe we imagine it's an act of will by a conscious entity (ie., like how we invent). When explaining the mind we suppose it's like one of our inventions. Absent an analogy of some kind it's quite hard to determine what features are salient. Objects have an essentially infinite number of properties.

> So, when explaining the universe we imagine it's an act of will by a conscious entity Unless I’m misunderstand you, that line of reasoning assumes one is religious.

We here means "our species".

Re: Edge detection doesn’t explain line drawing

#79

Post by mcpackieh »

lostlogin wrote: post #72
pavlov wrote: post #68

Earlier quoted context omitted.

“The world is on a turtle’s back” is Iroquois cosmology, at least.

Wow, thank you. I’d always thought this a Pratchett things. I see it has a history in India and China too. https://en.m.wikipedia.org/wiki/World_Turtle

How could at least two cultures without a communication line between them both come up with such a quirky idea? There must be some underlying truth to it.. I'm sold. World turtle is the answer.

Re: Edge detection doesn’t explain line drawing

#80

Post by marcosdumay »

HPsquared wrote: post #31
hprotagonist wrote: post #8

Earlier quoted context omitted.

ah, someone who paid attention in lecture! (incidentally; there’s a fairly deep literature of historians of science that have carefully documented that we describe ourselves as analogous to the most sophisticated technology of the day: see “to lose one’s temper”, “to blow a gasket”, “i got my wires crossed”, “sorry, cache miss”, … as metaphors and idioms of mental state through the centuries that reflect the cool tec…

Now the technology is starting to reflect the biology (neural networks). Inception!

Well, like evolutionary algorithms, the thing was designed to replicate some features of the natural one.
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