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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

#121

Post by notyoutube »

phkahler wrote: post #108
wpietri wrote: post #100

Earlier quoted context omitted.

Yeah, I have been guilty of that myself sometimes. This XKCD is a reminder to me: https://xkcd.com/793/

A manager once told me he'd never hire a PhD because once they complete the specialized work we hire them for, they inevitably get put on something outside their specialty - like your linked xkcd - and then their acceptance as experts along with that behavior causes real problems. Another time I had an older PhD moved to my area (outside his) where we were trying to meet a number of objectives. He said in a meeting t…

Yeah, bad PhDs, bad!

Edit: People being arrogant or know-it-all is probably not especially correlated with having obtained a PhD, but more with overall frame of mind, and I find this comment to be a uselessly negative ad-hominem.

Re: Edge detection doesn’t explain line drawing

#122

Post by bmicraft »

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…

I would put it like this:

Sharpening increases the high frequencies to cover the loss of even higher ones lost in downscaling.

Re: Edge detection doesn’t explain line drawing

#123

Post by DonHopkins »

krisoft wrote: post #39
CuriouslyC wrote: post #20

Earlier quoted context omitted.

The difference is turtles all the way down was literal, but heavenly clockwork and computer program perspectives are clear metaphors.

> turtles all the way down was literal Was it? What evidence do you have for that? If anything it sounds like the kind of verbal slapdown someone in authority would subject someone trying to be a smart alec. It is short. Easy to understand. And closes the kind of questioning. I would be very surprised if someone have considered it the literal truth, but of course have seen stranger things. > heavenly clockwork and co…

The "we're living in a simulation" theory is silly and self indulgent. If it's a simulation, then a simulation of WHAT that is REAL and exists OUTSIDE of a simulation? You still have to explain THAT. It's just as stupid and self-justifying and needlessly complex and arbitrarily made-up as any religion.

That is different from "we're living in a computational medium", which doesn't claim it's simulating something else, and is the only level of existence. (i.e. Fredkin et al)

Re: Edge detection doesn’t explain line drawing

#124

Post by codeflo »

phkahler wrote: post #108
wpietri wrote: post #100

Earlier quoted context omitted.

Yeah, I have been guilty of that myself sometimes. This XKCD is a reminder to me: https://xkcd.com/793/

A manager once told me he'd never hire a PhD because once they complete the specialized work we hire them for, they inevitably get put on something outside their specialty - like your linked xkcd - and then their acceptance as experts along with that behavior causes real problems. Another time I had an older PhD moved to my area (outside his) where we were trying to meet a number of objectives. He said in a meeting t…

I once worked with a PhD who claimed that basically any novel bit of coding was a "research problem", and thus not worth bothering. Using a hashtable to speed up an algorithm? Research problem. Using raw TCP instead of HTTP for a long running connection? Research problem. Implementing a graph algorithm you could read up on Wikipedia? Research problem. I think it was only when I solved three of those "research problems" in one week that he finally shut up.

Re: Edge detection doesn’t explain line drawing

#125

Post by bloppe »

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…

As someone who minored in neuroscience, I took away that edge detection is actually quite important to the way your vision works. Google search "center-surround receptive field of retinal ganglion cells". This happens in your eye, before the signal even enters the optic nerve to go to the brain. The brain itself is not detecting the edges; its input already has that information.

I was also struck by the similarity between the way your cochlea (the organ in your ear that picks up sound waves) functions, and the way a Fourier transform works. They both transform the signal into the frequency domain, but your cochlea does it via its mechanical properties rather than by convolving the signal with a bunch of sine waves.

Re: Edge detection doesn’t explain line drawing

#126

Post by plaidfuji »

cheschire wrote: post #2

I have a different hypothesis. I think line drawings are the representation of vectors. The details we focus on are the vectors with the highest magnitude of change, but that change is not always visual. For example, momentum often has an outsized representation in line drawings. Edges can be a high magnitude change as well, but it's not the only thing.

You’re on to something here. In the past I did a bunch of work on extracting line drawings from images, and the fundamental goal was always to vectorize the lines - then you get an abstract representation of the figure that you can scale up or down.

Re: Edge detection doesn’t explain line drawing

#127

Post by lelanthran »

Earw0rm wrote: post #61
dylan604 wrote: post #55

Earlier quoted context omitted.

>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.

He's an open book? I needed to let off some steam?

Do these count?

As the weekend wound down

Back-handed compliment

Re: Edge detection doesn’t explain line drawing

#128

Post by DonHopkins »

detourdog wrote: post #60
CuriouslyC wrote: post #20

Earlier quoted context omitted.

The difference is turtles all the way down was literal, but heavenly clockwork and computer program perspectives are clear metaphors.

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?

Dr Seuss's Yertle the Turtle is a metaphor for Hitler.

https://en.wikipedia.org/wiki/Yertle_the_Turtle_and_Other_St...

>Seuss has stated that the titular character Yertle represented Adolf Hitler, with Yertle's despotic rule of the pond and takeover of the surrounding area parallel to Hitler's regime in Germany and invasion of various parts of Europe.[3][4] Though Seuss made a point of not beginning the writing of his stories with a moral in mind, stating that "kids can see a moral coming a mile off", he was not against writing about issues; he said "there's an inherent moral in any story" and remarked that he was "subversive as hell".[5][6] "Yertle the Turtle" has variously been described as "autocratic rule overturned",[7] "a reaction against the fascism of World War II",[8] and "subversive of authoritarian rule".[9]

Re: Edge detection doesn’t explain line drawing

#129

Post by hprotagonist »

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.

> i would have been impressed if you had come up with a phrase from medieval tech, or roman/greek/egyptian

the dual metallurgical and psychological senses of “temper” are from the mid-14th c.

Re: Edge detection doesn’t explain line drawing

#130

Post by pixl97 »

notyoutube wrote: post #121
phkahler wrote: post #108

Earlier quoted context omitted.

A manager once told me he'd never hire a PhD because once they complete the specialized work we hire them for, they inevitably get put on something outside their specialty - like your linked xkcd - and then their acceptance as experts along with that behavior causes real problems. Another time I had an older PhD moved to my area (outside his) where we were trying to meet a number of objectives. He said in a meeting t…

Yeah, bad PhDs, bad! Edit: People being arrogant or know-it-all is probably not especially correlated with having obtained a PhD, but more with overall frame of mind, and I find this comment to be a uselessly negative ad-hominem.

Also people bringing this up remember the one time the PhD was wrong, while discounting the 99 times the PhD was right and kept them from doing a lot of fruitless work.
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