@TonyVladusich@mathstodon.xyz
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TonyVladusich

@TonyVladusich@mathstodon.xyz

I'm a computational neuroscientist & software engineer. Colors, photos, brains, nature, science, software & chess, preferably all at the same time!

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TonyVladusich, to random
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Going to start a thread here that I hope will eventually form the basis for a popular book entitled:

The Visual Perception of Everyday Things.

I thereby hope to motivate myself to add incrementally to this thread on a semi regular basis & get early feedback on the content.

TonyVladusich,
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The laws of physics govern how light is reflected or emitted from surfaces, and how light passes through surfaces. It therefore makes sense to begin our study of surface appearance by considering these physical laws. Light can be reflected in two substantive ways: it can reflected in all directions or in can reflect in primarily in one direction. We call these two types of reflections diffuse and specular, respectively.

Diffuse reflections give rise to what we perceive as matte surfaces, whereas specular reflections correspond to what we perceive as shiny, glossy or even metallic surfaces. There exists a continuum, of course, between the extremes or purely diffuse and specular reflections. A completely matte surface will reflect not reflect light coming from its surround at all, whereas a completely specular surface is a mirror, reflecting only the surrounding environment (Figure 2). The problem of how our visual system separates out diffuse and specular reflections during everyday perception will become a central focus of this book.

Figure 2. Diffuse and specular reflections (https://en.wikipedia.org/wiki/Diffuse_reflection).

6/

TonyVladusich,
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Another source of light reaching our eyes is literally sources of light. Light sources are said to emit light, and depending on the nature of the source, this light can be emitted in all directions or in specific directions. The sun emits light in all directions, for example, all though our eye can only sample light reaching it along direct lines of sight. A torch, by comparison, tends to emit light along a focused path that we call the beam. The problem of how our visual system distinguishes between light reflected from surfaces and emitted light will also become a key consideration in this book.

The final major source of light variation that we will consider is light that passes through objects, either entirely or partially. We say that objects are transparent if they transmit light through their surfaces, and we say objects are translucent if light only partially penetrates the object before being emitted at some other point of the surface. This latter effect is called sub-surface scattering and it is a physical phenomenon that lies somewhere between light reflection and emission (Figure 3).

Thus, we arrive at the four major sources of variation in sensed light that inform us of the visual world: diffuse/specular light reflection and light emission/scattering.

Figure 3. Light scattering (https://en.wikipedia.org/wiki/Subsurface_scattering).

ryanbooker, to random
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You’d think, after 15 years autocorrect would realise “tot he” should be “to the”.

TonyVladusich,
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@jelly @ryanbooker

Well, it’s fucked

TonyVladusich,
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@ryanbooker

Is it just me or has auto correct gotten way worse lately? I assume some AI garbage has slipped into the mix.

TonyVladusich,
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@ryanbooker @jelly

Yeah, probably the AI garbage preferring one over the other because there is no semantic understanding there. It’s just the law of averages crushing everything down to a point. Apple really nailed it with that iPad ad.

TonyVladusich, to random
@TonyVladusich@mathstodon.xyz avatar

Me: I’m cooking pizza
Wife: can u pls put vegetables on it, like mushrooms?
Me: what you don’t think I know what a vegetable is?
Wife: …
Me: fair point

dave, to random
@dave@social.lightbeamapps.com avatar

Some days I want to defederate from the world 😅

TonyVladusich,
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@dave

The lack of any sort of skepticism, or even critical thought, is frightening, albeit not unexpected.

TonyVladusich,
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@dave

Please take one AI and get some bed rest, Dave.

matthewconroy, (edited ) to mathematics
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I'm surprised it took me this long to add the Reuleuax triangle to my table of isoperimetric ratios. It's curiously close to an integer. https://sites.math.washington.edu//~conroy/isoperimetrics/isoperimetrics.pdf

TonyVladusich,
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@matthewconroy

You might dig this paper by a former colleague of mine.

https://www.math.ucdavis.edu/~saito/data/clustering/grady-schwartz-pami.pdf

dave, to random
@dave@social.lightbeamapps.com avatar

Watching the Kotlin Multiplatform ‘24 keynote.

It’s a breath of fresh air after years of Apple’s super-highly-polished WWDC ones.

Specifically: people falter naturally like real humans giving talks, multiple companies involved showing some industry collaboration. Something that’s just not present at WWDC re: Swift.

TonyVladusich,
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@dave @obrhoff

and so the "hello fellow android devs" meme was born.

johncarlosbaez, to random
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I want to read this book: A Darwinian Survival Guide. Sounds like a realistic view of what we need to do now. You can read an interview with one author, the biologist Daniel Brooks. A quote:

...

Daniel Brooks: What can we begin doing now that will increase the chances that those elements of technologically-dependent humanity will survive a general collapse, if that happens as a result of our unwillingness to begin to do anything effective with respect to climate change and human existence?

Peter Watts: So to be clear, you’re not talking about forestalling the collapse —

Daniel Brooks: No.

Peter Watts: — you’re talking about passing through that bottleneck and coming out the other side with some semblance of what we value intact.

Daniel Brooks: Yeah, that’s right. It is conceivable that if all of humanity suddenly decided to change its behavior, right now, we would emerge after 2050 with most everything intact, and we would be “OK.” We don’t think that’s realistic. It is a possibility, but we don’t think that’s a realistic possibility. We think that, in fact, most of humanity is committed to business as usual, and that’s what we’re really talking about: What can we begin doing now to try to shorten the period of time after the collapse, before we “recover”? In other words — and this is in analogy with Asimov’s Foundation trilogy — if we do nothing, there’s going to be a collapse and it’ll take 30,000 years for the galaxy to recover. But if we start doing things now, then it maybe only takes 1,000 years to recover. So using that analogy, what can some human beings start to do now that would shorten the period of time necessary to recover?

https://thereader.mitpress.mit.edu/the-collapse-is-coming-will-humanity-adapt/

TonyVladusich,
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@johncarlosbaez

Some deep stuff here:

"Stepping back a bit. Darwin told us in 1859 that what we had been doing for the last 10,000 or so years was not going to work. But people didn’t want to hear that message. So along came a sociologist who said, “It’s OK; I can fix Darwinism.” This guy’s name was Herbert Spencer, and he said, “I can fix Darwinism. We’ll just call it natural selection, but instead of survival of what’s-good-enough-to-survive-in-the-future, we’re going to call it survival of the fittest, and it’s whatever is best now.” Herbert Spencer was instrumental in convincing most biologists to change their perspective from “evolution is long-term survival” to “evolution is short-term adaptation.” And that was consistent with the notion of maximizing short term profits economically, maximizing your chances of being reelected, maximizing the collection plate every Sunday in the churches, and people were quite happy with this."

matthewconroy, (edited ) to random
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Grading exams: it pains me to see some of my Calc II students using the quadratic formula to solve (b^2-3b=0). #exams #grading #calculus

TonyVladusich,
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@matthewconroy

It’s interesting I think because clearly they’ve not understood why the need to apply the quadratic formula in the first place!

demofox, to random
@demofox@mastodon.gamedev.place avatar

My video's power level is over 9000

TonyVladusich,
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@demofox

The left still has an extraordinary glassy appearance.

TonyVladusich, to random
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The Dirichlet problem

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

TonyVladusich, to random
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Question for Swift devs: What are good use cases for resultBuilders? How do you decide if a resultBuilder is overkill? Aside from lots of boilerplate (and perhaps the difficulty in understanding them for other devs?), are there other down sides of using resultBuilders?

TonyVladusich, to random
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Scientists say your brain is so powerful it can bench press an elephant

https://www.indy100.com/science-tech/human-brain-neurons-study

TonyVladusich, to random
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I just remembered a dream I had last night about @huwr. You rocked up to my house in a van and I hopped in (innocent that I am). I then poked you on the arm and asked “Are you real?”, and you replied “Of course”. I then promptly woke up and said to myself “liar”.

TonyVladusich, to random
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meanwhile over in bizarro world https://twitter.com/MarkusDeserno/status/1649598441750769665?s=20

TonyVladusich, to random
@TonyVladusich@mathstodon.xyz avatar

Fell and Broke my hand, much hurties

TonyVladusich, to random
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My wife and I have Covid. This is the first time either of us has tested positive. I beg for the release of death.

TonyVladusich, to random
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Just watched Top Gun: Maverick.

It was horrendous.

I thoroughly enjoyed it.

TonyVladusich, to random
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The perception of gloss depends on highlight congruence with surface shading

https://jov.arvojournals.org/article.aspx?articleid=2121251

Studies have shown that displacing specular highlights from their natural locations in images reduces perceived surface gloss. Here, we assessed the extent to which perceived gloss depends on congruence in the position and orientation of specular highlights relative to surface shape and the diffuse shading from which surface shape is recovered. The position and orientation congruence of specular highlights with diffuse shading was altered while preserving their compatibility with physical surface shape (Experiment 1). We found that perceived gloss diminished as the position of highlights became incompatible wit h the surface's global diffuse shading maxima. These results suggest the visual system assesses both position and orientation congruence between specular highlights and diffuse shading to estimate surface gloss.

TonyVladusich, to random
@TonyVladusich@mathstodon.xyz avatar

fucking why Apple, why?!

TonyVladusich, to random
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Me mate, dangerous Dave https://www.youtube.com/watch?v=0ZYbYymEwAA

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