gdalgorithms-list

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Samuel M. <sam...@go...>]

Somehow OT, I think what was missing in the video for the mentioned
siggraph paper (http://gamma.cs.unc.edu/PrecompWaveSim/), was some
sort of model for the human ear. I strongly suspect that for the
virtual recording they just placed two undirected virtual microphones
some 20cm apart, because with headphones it still sounded as though
every sound source was inside your head (Though the sense of space was
great). And I guess that's because in the virtual recording the
virtual external ear is missing, which is mainly responsible for
directional hearing in the real world. Just listen to these videos
(with earphones!) if you have no idea what I'm talking about (these
both model the external ear in some way, I'm not sure if they also
have real room acoustic modelling):

binaurial demonstration video:
http://www.youtube.com/watch?v=vfViBtIjK4c&feature=related <-- watch
out for the telephone ;)
virtual haircut: http://www.youtube.com/watch?v=8IXm6SuUigI&feature=related

Unfortunately there are very little details available publicly, and
those videos have been around for a long time, so I guess the research
around the subject somehow died.


BTW, I'm all for better, more sophisticated and computationally
expensive sound in games! Ego-shooters, horror games, how they could
benefit from the equivalent of the telephone above! ;)


Samuel


On Wed, Jul 21, 2010 at 8:39 PM, Peter-Pike Sloan
<pet...@ho...> wrote:
> Haven't read the whole thread, but here is a paper that will be presented at
> siggraph this year:
> http://gamma.cs.unc.edu/PrecompWaveSim/
> You would clearly need to scale back both memory usage and run-time to make
> this viable for games of course.
> Peter-Pike
>
> ________________________________
> Date: Tue, 20 Jul 2010 17:13:06 +0100
> From: ni...@gm...
> To: gda...@li...
> Subject: Re: [Algorithms] Spherical harmonics for room acoustic modelling
>
> Actually I implemented a basic beam tree that used the material properties
> to estimate reverb in closed environments. The beam tree was too large for
> detailed outdoor environments, but I suppose if you have a decent mesh
> reduction algorithm you could scale it down, I just never had the time to
> finish this work.
>
> Cheers,
> -Ken Noland
>
> On Sun, Jul 18, 2010 at 11:03 AM, Jon Watte <jw...@gm...> wrote:
>
>  I'd have doubts you'd get good enough response time on CPU alone
>
> Actually, the CPU can give you excellent response times if you're using a
> convolution based solution. DJBFFT is a very high performance, unencumbered
> convolution implementation, and it takes a minimal amount of CPU for a
> single sound stream. The problem comes when you want to combine delay lines
> to do overlap-add long convolution (or use the variable-window-size that's
> allegedly still patented by Lake DSP). It starts adding up! The GPU might be
> good at larger convolutions, but it has higher latency than the CPU.
> I'm not sure Spherical Harmonics is the right solution. Sound reflection is
> a function of frequency mapping to absorption and directional spread. And
> whereas the eye is only sensitive to three separate frequencies, the ear is
> sensitive to thousands... And in SH based PRT, you often collapse the
> direction-dependent response into a single term, and filter the three
> frequencies using a separate RGB "diffuse reflectance" texture. If you
> applied the same to sound, you'd probably get a better than nothing, but you
> might only get good enough that the problems start to become obvious :-)
> (Bass, Mid and Treble, with a fixed reflectance function)
> Sincerely,
> jw
>
> --
> Americans might object: there is no way we would sacrifice our living
> standards for the benefit of people in the rest of the world. Nevertheless,
> whether we get there willingly or not, we shall soon have lower consumption
> rates, because our present rates are unsustainable.
>
>
>
> On Sat, Jul 17, 2010 at 2:23 PM, Oscar Forth
> <os...@tr...> wrote:
>
> OK maybe not spherical harmonic based but gives the same sorta results and,
> therefore, just as interesting :)
>
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Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Peter-Pike S. <pet...@ho...>]

Haven't read the whole thread, but here is a paper that will be presented at siggraph this year:
http://gamma.cs.unc.edu/PrecompWaveSim/
You would clearly need to scale back both memory usage and run-time to make this viable for games of course.
Peter-Pike

Date: Tue, 20 Jul 2010 17:13:06 +0100
From: ni...@gm...
To: gda...@li...
Subject: Re: [Algorithms] Spherical harmonics for room acoustic modelling

Actually I implemented a basic beam tree that used the material properties to estimate reverb in closed environments. The beam tree was too large for detailed outdoor environments, but I suppose if you have a decent mesh reduction algorithm you could scale it down, I just never had the time to finish this work.


Cheers,
-Ken Noland

On Sun, Jul 18, 2010 at 11:03 AM, Jon Watte <jw...@gm...> wrote:




 I'd have doubts you'd get good enough response time on CPU alone


Actually, the CPU can give you excellent response times if you're using a convolution based solution. DJBFFT is a very high performance, unencumbered convolution implementation, and it takes a minimal amount of CPU for a single sound stream. The problem comes when you want to combine delay lines to do overlap-add long convolution (or use the variable-window-size that's allegedly still patented by Lake DSP). It starts adding up! The GPU might be good at larger convolutions, but it has higher latency than the CPU.

I'm not sure Spherical Harmonics is the right solution. Sound reflection is a function of frequency mapping to absorption and directional spread. And whereas the eye is only sensitive to three separate frequencies, the ear is sensitive to thousands... And in SH based PRT, you often collapse the direction-dependent response into a single term, and filter the three frequencies using a separate RGB "diffuse reflectance" texture. If you applied the same to sound, you'd probably get a better than nothing, but you might only get good enough that the problems start to become obvious :-) (Bass, Mid and Treble, with a fixed reflectance function)


Sincerely,
jw

--
Americans might object: there is no way we would sacrifice our living standards for the benefit of people in the rest of the world. Nevertheless, whether we get there willingly or not, we shall soon have lower consumption rates, because our present rates are unsustainable. 






On Sat, Jul 17, 2010 at 2:23 PM, Oscar Forth <os...@tr...> wrote:


OK maybe not spherical harmonic based but gives the same sorta results and, therefore, just as interesting :)


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Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Ken N. <ni...@gm...>]

Actually I implemented a basic beam tree that used the material properties
to estimate reverb in closed environments. The beam tree was too large for
detailed outdoor environments, but I suppose if you have a decent mesh
reduction algorithm you could scale it down, I just never had the time to
finish this work.

Cheers,
-Ken Noland

On Sun, Jul 18, 2010 at 11:03 AM, Jon Watte <jw...@gm...> wrote:

>
>  I'd have doubts you'd get good enough response time on CPU alone
>
>
>
> Actually, the CPU can give you excellent response times if you're using a
> convolution based solution. DJBFFT is a very high performance, unencumbered
> convolution implementation, and it takes a minimal amount of CPU for a
> single sound stream. The problem comes when you want to combine delay lines
> to do overlap-add long convolution (or use the variable-window-size that's
> allegedly still patented by Lake DSP). It starts adding up! The GPU might be
> good at larger convolutions, but it has higher latency than the CPU.
>
> I'm not sure Spherical Harmonics is the right solution. Sound reflection is
> a function of frequency mapping to absorption and directional spread. And
> whereas the eye is only sensitive to three separate frequencies, the ear is
> sensitive to thousands... And in SH based PRT, you often collapse the
> direction-dependent response into a single term, and filter the three
> frequencies using a separate RGB "diffuse reflectance" texture. If you
> applied the same to sound, you'd probably get a better than nothing, but you
> might only get good enough that the problems start to become obvious :-)
> (Bass, Mid and Treble, with a fixed reflectance function)
>
> Sincerely,
>
> jw
>
>
> --
> Americans might object: there is no way we would sacrifice our living
> standards for the benefit of people in the rest of the world. Nevertheless,
> whether we get there willingly or not, we shall soon have lower consumption
> rates, because our present rates are unsustainable.
>
>
>
> On Sat, Jul 17, 2010 at 2:23 PM, Oscar Forth <
> os...@tr...> wrote:
>
>> OK maybe not spherical harmonic based but gives the same sorta results
>> and, therefore, just as interesting :)
>>
>>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Sprint
> What will you do first with EVO, the first 4G phone?
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> _______________________________________________
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> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
> Archives:
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>

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Jon W. <jw...@gm...>]

>  I'd have doubts you'd get good enough response time on CPU alone



Actually, the CPU can give you excellent response times if you're using a
convolution based solution. DJBFFT is a very high performance, unencumbered
convolution implementation, and it takes a minimal amount of CPU for a
single sound stream. The problem comes when you want to combine delay lines
to do overlap-add long convolution (or use the variable-window-size that's
allegedly still patented by Lake DSP). It starts adding up! The GPU might be
good at larger convolutions, but it has higher latency than the CPU.

I'm not sure Spherical Harmonics is the right solution. Sound reflection is
a function of frequency mapping to absorption and directional spread. And
whereas the eye is only sensitive to three separate frequencies, the ear is
sensitive to thousands... And in SH based PRT, you often collapse the
direction-dependent response into a single term, and filter the three
frequencies using a separate RGB "diffuse reflectance" texture. If you
applied the same to sound, you'd probably get a better than nothing, but you
might only get good enough that the problems start to become obvious :-)
(Bass, Mid and Treble, with a fixed reflectance function)

Sincerely,

jw


--
Americans might object: there is no way we would sacrifice our living
standards for the benefit of people in the rest of the world. Nevertheless,
whether we get there willingly or not, we shall soon have lower consumption
rates, because our present rates are unsustainable.



On Sat, Jul 17, 2010 at 2:23 PM, Oscar Forth <
os...@tr...> wrote:

> OK maybe not spherical harmonic based but gives the same sorta results and,
> therefore, just as interesting :)
>
>

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Oscar F. <os...@tr...>]

OK maybe not spherical harmonic based but gives the same sorta results and,
therefore, just as interesting :)

On 17 July 2010 22:13, Veikko Eeva <vei...@ik...> wrote:

>
> From: Oscar Forth <os...@tr...>
> > Spherical harmonics for room acoustic modelling
>  > [...]
>
> Not exactly directly related to the original question, but to feed the
> discussion and curious minds regarding sound waves also in games, I
> thought to share that Intel just recently published a paper on this.
>
> Interactive Geometric Sound Propagation and Rendering
> by Micah Taylor, Anish Chandak, Lakulish Antani, Dinesh Manocha
> available at
>
> http://software.intel.com/en-us/articles/interactive-geometric-sound-propagation-and-rendering/
>
> "
> *Abstract*
>
> We describe a novel algorithm and system for sound propagation and
> rendering in virtual environments and media applications. Our approach
> uses geometric propagation techniques for fast computation of
> propagation paths from a source to a listener and takes into account
> specular reflections, diffuse reflections, and edge diffraction. In
> order to perform fast path computation, we use a unified ray-based
> representation to efficiently trace discrete rays as well as volumetric
> ray-frusta. Furthermore, our propagation algorithm scales well with the
> number of cores, and uses interactive audio rendering technique to
> generate spatialized audio signals. The overall approach can render
> sound in dynamic scenes, allowing source, listener, and obstacle motion,
> and we show its performance on game-like and architectural environments.
> To the best of our knowledge, this is the first interactive sound
> rendering system that can perform plausible sound propagation and
> rendering in dynamic virtual environments.
> "
>
>
> Cheers,
> Veikko Eeva
>
>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Sprint
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Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Veikko E. <vei...@ik...>]

From: Oscar Forth <os...@tr...>
> Spherical harmonics for room acoustic modelling
 > [...]

Not exactly directly related to the original question, but to feed the 
discussion and curious minds regarding sound waves also in games, I 
thought to share that Intel just recently published a paper on this.

Interactive Geometric Sound Propagation and Rendering
by Micah Taylor, Anish Chandak, Lakulish Antani, Dinesh Manocha
available at 
http://software.intel.com/en-us/articles/interactive-geometric-sound-propagation-and-rendering/

"
*Abstract*

We describe a novel algorithm and system for sound propagation and 
rendering in virtual environments and media applications. Our approach 
uses geometric propagation techniques for fast computation of 
propagation paths from a source to a listener and takes into account 
specular reflections, diffuse reflections, and edge diffraction. In 
order to perform fast path computation, we use a unified ray-based 
representation to efficiently trace discrete rays as well as volumetric 
ray-frusta. Furthermore, our propagation algorithm scales well with the 
number of cores, and uses interactive audio rendering technique to 
generate spatialized audio signals. The overall approach can render 
sound in dynamic scenes, allowing source, listener, and obstacle motion, 
and we show its performance on game-like and architectural environments. 
To the best of our knowledge, this is the first interactive sound 
rendering system that can perform plausible sound propagation and 
rendering in dynamic virtual environments.
"


Cheers,
Veikko Eeva

[Algorithms] Fwd: Spherical harmonics for room acoustic modelling

[Oscar F. <os...@tr...>]

I got this mail direct to my e-Mail so I've forwarded it to the mailing list
:)

Thanks Stephen.  VERY interesting post :)

---------- Forwarded message ----------
From: stephen mccaul <ste...@gm...>
Date: 17 July 2010 21:44
Subject: Re: [Algorithms] Spherical harmonics for room acoustic modelling
To: os...@tr...


My list response bounced. silly email addresses.

So i will send it to you directly.



http://en.wikipedia.org/wiki/Ambisonics

uses spherical harmonics to compute a 3d approximation of the pressure about
a point.

There are a variety of people working on real time room response technology.

Here are a few papers:

http://www-sop.inria.fr/reves/Nicolas.Tsingos/publis/ntsin_aes35_reverb.pdf
http://www.aes.org/e-lib/browse.cfm?elib=15157
http://www.mee.tcd.ie/~gkearney/ResearchPapers/Masterson_Kearney_and_Boland_AES35_Submission


Its a bit expensive to run a convolution per voice given today's consoles
(maybe on the ps3 or if you wrote
your own decoder so you can keep the signal in the frequency domain from the
get go.





Oscar Forth wrote:

> I will admit first off I don't have a great knowledge of things like
> Pre-computed Radiance Transfer but I was having a chat with a colleague
> recently on how audio research lags behind video research in gaming.
>
> One idea that we were talking about is using spherical harmonics in a
> similar way to PRT to do some sort of Pre-computed Acoustic Transfer.
>
> Basically you'd add a new material type to a room that would give you the
> sound reflectivity of a given surface.   You could then use the same
> techniques (obviously calculated with something like OpenCL) to give you a
> good model of how sound moves round a room.  Has anyone done anything like
> this?
>
> It kinda struck me that you'd be able to model things like acoustic
> reflections off a hard surface, acoustic dispersion from soft surfaces as
> well as getting things like occluders thrown in as a bonus.  Add to that
> you
> could use the same techniques as are used for translucent surfaces to model
> sound transfer through a surface and the slight bending of audio round
> corners.
>
> Are there any papers on the subject at all?  It struck me as something
> worth
> finding more out about as it would give the ability to create truly rich
> sound scapes with very little actual fiddling needed to get it right.
>  You'd
> just pass the model through your PAT calculation engine then play sounds
> and
> get them playing right.
>
> Any thoughts?
>
> Cheers!
>
> Oscar
>
>
>
> ------------------------------------------------------------------------
>
>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Sprint
> What will you do first with EVO, the first 4G phone?
> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
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>
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Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Don W. <don...@ya...>]

You might want to take a look at Ambisonics as a good starting point:

    http://en.wikipedia.org/wiki/Ambisonics

The Furse-Malham set extend this to 2nd and 3rd order SH:

    http://www.muse.demon.co.uk/3daudio.html

This kind of tech was effectively used in DiRT by Codemasters:

    
http://blog.ambisonia.com/2007/08/30/interview-with-simon-goodwin-of-codemasters-on-the-ps3-game-dirt-and-ambisonics/


And of course, you can rotate them... ;)

Cheers,
- Don

    





________________________________
From: Oscar Forth <os...@tr...>
To: Game Development Algorithms <gda...@li...>
Sent: Sat, July 17, 2010 9:22:26 PM
Subject: Re: [Algorithms] Spherical harmonics for room acoustic modelling

Sweet!  I'll take a look, ta :)

You wouldn't happen to have any links that would save me a bit of time and 
google trawling?  No worries if not :)


On 17 July 2010 21:03, Deano <de...@ra...> wrote:

Search for wave tracing in the literature. For acoustics, wave behavior is vital 
unlike most lighting equations, as such you need to model waves transfer and 
also for most audio surfaces unlike visual surfaces they are not 100% reflective 
and so subsurface scattering is way more important.
> 
>There is some interesting work out there, including at least one GPGPU real-time 
>system.
> 
>Deano
> 
>From:Oscar Forth [mailto:os...@tr...] 
>Sent: 17 July 2010 20:10
>To: Game Development Algorithms
>Subject: [Algorithms] Spherical harmonics for room acoustic modelling
> 
>I will admit first off I don't have a great knowledge of things like 
>Pre-computed Radiance Transfer but I was having a chat with a colleague recently 
>on how audio research lags behind video research in gaming.
> 
>One idea that we were talking about is using spherical harmonics in a similar 
>way to PRT to do some sort of Pre-computed Acoustic Transfer.
> 
>Basically you'd add a new material type to a room that would give you the sound 
>reflectivity of a given surface.   You could then use the same techniques 
>(obviously calculated with something like OpenCL) to give you a good model of 
>how sound moves round a room.  Has anyone done anything like this?
> 
>It kinda struck me that you'd be able to model things like acoustic reflections 
>off a hard surface, acoustic dispersion from soft surfaces as well as getting 
>things like occluders thrown in as a bonus.  Add to that you could use the same 
>techniques as are used for translucent surfaces to model sound transfer through 
>a surface and the slight bending of audio round corners.
> 
>Are there any papers on the subject at all?  It struck me as something worth 
>finding more out about as it would give the ability to create truly rich sound 
>scapes with very little actual fiddling needed to get it right.  You'd just pass 
>the model through your PAT calculation engine then play sounds and get them 
>playing right.
> 
>Any thoughts?
> 
>Cheers!
> 
>Oscar
>------------------------------------------------------------------------------
>This SF.net email is sponsored by Sprint
>What will you do first with EVO, the first 4G phone?
>Visit sprint.com/first-- http://p.sf.net/sfu/sprint-com-first
>_______________________________________________
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>



      

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Oscar F. <os...@tr...>]

Sweet!  I'll take a look, ta :)

You wouldn't happen to have any links that would save me a bit of time and
google trawling?  No worries if not :)

On 17 July 2010 21:03, Deano <de...@ra...> wrote:

>  Search for wave tracing in the literature. For acoustics, wave behavior
> is vital unlike most lighting equations, as such you need to model waves
> transfer and also for most audio surfaces unlike visual surfaces they are
> not 100% reflective and so subsurface scattering is way more important.
>
>
>
> There is some interesting work out there, including at least one GPGPU
> real-time system.
>
>
>
> Deano
>
>
>
> *From:* Oscar Forth [mailto:os...@tr...]
> *Sent:* 17 July 2010 20:10
> *To:* Game Development Algorithms
> *Subject:* [Algorithms] Spherical harmonics for room acoustic modelling
>
>
>
> I will admit first off I don't have a great knowledge of things like
> Pre-computed Radiance Transfer but I was having a chat with a colleague
> recently on how audio research lags behind video research in gaming.
>
>
>
> One idea that we were talking about is using spherical harmonics in a
> similar way to PRT to do some sort of Pre-computed Acoustic Transfer.
>
>
>
> Basically you'd add a new material type to a room that would give you the
> sound reflectivity of a given surface.   You could then use the same
> techniques (obviously calculated with something like OpenCL) to give you a
> good model of how sound moves round a room.  Has anyone done anything like
> this?
>
>
>
> It kinda struck me that you'd be able to model things like acoustic
> reflections off a hard surface, acoustic dispersion from soft surfaces as
> well as getting things like occluders thrown in as a bonus.  Add to that you
> could use the same techniques as are used for translucent surfaces to model
> sound transfer through a surface and the slight bending of audio round
> corners.
>
>
>
> Are there any papers on the subject at all?  It struck me as something
> worth finding more out about as it would give the ability to create truly
> rich sound scapes with very little actual fiddling needed to get it right.
>  You'd just pass the model through your PAT calculation engine then play
> sounds and get them playing right.
>
>
>
> Any thoughts?
>
>
>
> Cheers!
>
>
>
> Oscar
>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Sprint
> What will you do first with EVO, the first 4G phone?
> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
> _______________________________________________
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>

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Deano <de...@ra...>]

Search for wave tracing in the literature. For acoustics, wave behavior is
vital unlike most lighting equations, as such you need to model waves
transfer and also for most audio surfaces unlike visual surfaces they are
not 100% reflective and so subsurface scattering is way more important.

 

There is some interesting work out there, including at least one GPGPU
real-time system.

 

Deano

 

From: Oscar Forth [mailto:os...@tr...] 
Sent: 17 July 2010 20:10
To: Game Development Algorithms
Subject: [Algorithms] Spherical harmonics for room acoustic modelling

 

I will admit first off I don't have a great knowledge of things like
Pre-computed Radiance Transfer but I was having a chat with a colleague
recently on how audio research lags behind video research in gaming.

 

One idea that we were talking about is using spherical harmonics in a
similar way to PRT to do some sort of Pre-computed Acoustic Transfer.

 

Basically you'd add a new material type to a room that would give you the
sound reflectivity of a given surface.   You could then use the same
techniques (obviously calculated with something like OpenCL) to give you a
good model of how sound moves round a room.  Has anyone done anything like
this?

 

It kinda struck me that you'd be able to model things like acoustic
reflections off a hard surface, acoustic dispersion from soft surfaces as
well as getting things like occluders thrown in as a bonus.  Add to that you
could use the same techniques as are used for translucent surfaces to model
sound transfer through a surface and the slight bending of audio round
corners.

 

Are there any papers on the subject at all?  It struck me as something worth
finding more out about as it would give the ability to create truly rich
sound scapes with very little actual fiddling needed to get it right.  You'd
just pass the model through your PAT calculation engine then play sounds and
get them playing right.

 

Any thoughts?

 

Cheers!

 

Oscar

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Oscar F. <os...@tr...>]

I should also add that this is more from the point of view as to how it
would work.  Even if we don't have the power now we may well do soon and its
more of a spare time project I'm thinking of.

Also I still have a Diamond Monster MX300 lieing around.  I'd still use it
if you could get drivers these days :(

On 17 July 2010 21:04, Oscar Forth <os...@tr...> wrote:

> You can calculate the impulse response of any environment analytically
>> these days.
>> The main problem is that it's really computationally expensive to apply a
>> very long convolution response to all sound.
>> Creative tried 10-15 years ago to drive up the compute power for sound,
>> with the Live! series (based on E-mu DSPs) and the (somewhat finicky) EAX
>> API.
>> Another company, called Aureal, actually went a step further, and allowed
>> you to specify a crude representation of your geometry, but they died before
>> they could get mainstream traction.
>> However, what actually happened was that nobody cared, and sound is now
>> just a 50 cent DAC hooked to a raw DMA engine on the south bridge of the
>> motherboard, so any processing has to use that precious resource, the
>> very-expensive general-purpose core CPU.
>>
>
> This is a real shame because good sound REALLY enhances the sense of
> immersion in any game. Echoes in a valley for example.
>
> I guess the problem is that I've taken a 2.5 year hiatus from games dev and
> have been working on hardcore audio processing algorithms.  As a result
> whenever I play a game now I'm ACUTELY aware of just how badly wrong things
> sound.  Its either hugely exaggerated or just plain wrong.
>
>
>> Good luck telling your AI, rendering and physics people that you'd like
>> 1/4 the CPU power for applying audio effects :-(
>>
>
> hehehe ... I was more thinking about 1/4 of the GPU power as I'd have
> doubts you'd get good enough response time on CPU alone ...
>

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Oscar F. <os...@tr...>]

>
> I don't have much to add on a technical level, other than to say I really
> like the sound of this idea (no pun intended).
>

badum tish! ;)


> It does seem like maybe the problem has too many dimensions for just a
> simple SH encoded precomputation though. My SH powers are limited, but in
> lighting terms your problem sounds similar to determining the light passing
> through a point in space (the listener's head) from a single local light
> source.
>

Effectively yes ... thats what you'd be doing.  You may be right on SH not
being up to it but thats why I thought I'd start this discussion :)


> The folks over at Crytek are doing some interesting things with "light
> propagation volumes" for their new tech. Seems like a similar approach might
> work for determining audio propagation as well.
> http://www.crytek.com/technology/presentations/


Cheers I'll take look.  Gonna have to switch my head over to "Understanding
unfathomable language mode" ... perhaps the few cans of cider wasn't SUCH a
great plan :D

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Oscar F. <os...@tr...>]

>
> You can calculate the impulse response of any environment analytically
> these days.
> The main problem is that it's really computationally expensive to apply a
> very long convolution response to all sound.
> Creative tried 10-15 years ago to drive up the compute power for sound,
> with the Live! series (based on E-mu DSPs) and the (somewhat finicky) EAX
> API.
> Another company, called Aureal, actually went a step further, and allowed
> you to specify a crude representation of your geometry, but they died before
> they could get mainstream traction.
> However, what actually happened was that nobody cared, and sound is now
> just a 50 cent DAC hooked to a raw DMA engine on the south bridge of the
> motherboard, so any processing has to use that precious resource, the
> very-expensive general-purpose core CPU.
>

This is a real shame because good sound REALLY enhances the sense of
immersion in any game. Echoes in a valley for example.

I guess the problem is that I've taken a 2.5 year hiatus from games dev and
have been working on hardcore audio processing algorithms.  As a result
whenever I play a game now I'm ACUTELY aware of just how badly wrong things
sound.  Its either hugely exaggerated or just plain wrong.


> Good luck telling your AI, rendering and physics people that you'd like 1/4
> the CPU power for applying audio effects :-(
>

hehehe ... I was more thinking about 1/4 of the GPU power as I'd have doubts
you'd get good enough response time on CPU alone ...

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Jeff R. <je...@8m...>]

I don't have much to add on a technical level, other than to say I really
like the sound of this idea (no pun intended).

It does seem like maybe the problem has too many dimensions for just a
simple SH encoded precomputation though. My SH powers are limited, but in
lighting terms your problem sounds similar to determining the light passing
through a point in space (the listener's head) from a single local light
source.

The folks over at Crytek are doing some interesting things with "light
propagation volumes" for their new tech. Seems like a similar approach might
work for determining audio propagation as well.
http://www.crytek.com/technology/presentations/

Jeff

On Sat, Jul 17, 2010 at 2:09 PM, Oscar Forth <
os...@tr...> wrote:

> I will admit first off I don't have a great knowledge of things like
> Pre-computed Radiance Transfer but I was having a chat with a colleague
> recently on how audio research lags behind video research in gaming.
>
> One idea that we were talking about is using spherical harmonics in a
> similar way to PRT to do some sort of Pre-computed Acoustic Transfer.
>
> Basically you'd add a new material type to a room that would give you the
> sound reflectivity of a given surface.   You could then use the same
> techniques (obviously calculated with something like OpenCL) to give you a
> good model of how sound moves round a room.  Has anyone done anything like
> this?
>
> It kinda struck me that you'd be able to model things like acoustic
> reflections off a hard surface, acoustic dispersion from soft surfaces as
> well as getting things like occluders thrown in as a bonus.  Add to that you
> could use the same techniques as are used for translucent surfaces to model
> sound transfer through a surface and the slight bending of audio round
> corners.
>
> Are there any papers on the subject at all?  It struck me as something
> worth finding more out about as it would give the ability to create truly
> rich sound scapes with very little actual fiddling needed to get it right.
>  You'd just pass the model through your PAT calculation engine then play
> sounds and get them playing right.
>
> Any thoughts?
>
> Cheers!
>
> Oscar
>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Sprint
> What will you do first with EVO, the first 4G phone?
> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
> _______________________________________________
> GDAlgorithms-list mailing list
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> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
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> http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
>



-- 
Jeff Russell
Engineer, 8monkey Labs
www.8monkeylabs.com

Re: [Algorithms] Spherical harmonics for room acoustic modelling

[Jon W. <jw...@gm...>]

You can calculate the impulse response of any environment analytically these
days.
The main problem is that it's really computationally expensive to apply a
very long convolution response to all sound.
Creative tried 10-15 years ago to drive up the compute power for sound, with
the Live! series (based on E-mu DSPs) and the (somewhat finicky) EAX API.
Another company, called Aureal, actually went a step further, and allowed
you to specify a crude representation of your geometry, but they died before
they could get mainstream traction.
However, what actually happened was that nobody cared, and sound is now just
a 50 cent DAC hooked to a raw DMA engine on the south bridge of the
motherboard, so any processing has to use that precious resource, the
very-expensive general-purpose core CPU.
Good luck telling your AI, rendering and physics people that you'd like 1/4
the CPU power for applying audio effects :-(

Sincerely,

jw


--
Americans might object: there is no way we would sacrifice our living
standards for the benefit of people in the rest of the world. Nevertheless,
whether we get there willingly or not, we shall soon have lower consumption
rates, because our present rates are unsustainable.



On Sat, Jul 17, 2010 at 12:09 PM, Oscar Forth <
os...@tr...> wrote:

> I will admit first off I don't have a great knowledge of things like
> Pre-computed Radiance Transfer but I was having a chat with a colleague
> recently on how audio research lags behind video research in gaming.
>
> One idea that we were talking about is using spherical harmonics in a
> similar way to PRT to do some sort of Pre-computed Acoustic Transfer.
>
> Basically you'd add a new material type to a room that would give you the
> sound reflectivity of a given surface.   You could then use the same
> techniques (obviously calculated with something like OpenCL) to give you a
> good model of how sound moves round a room.  Has anyone done anything like
> this?
>
> It kinda struck me that you'd be able to model things like acoustic
> reflections off a hard surface, acoustic dispersion from soft surfaces as
> well as getting things like occluders thrown in as a bonus.  Add to that you
> could use the same techniques as are used for translucent surfaces to model
> sound transfer through a surface and the slight bending of audio round
> corners.
>
> Are there any papers on the subject at all?  It struck me as something
> worth finding more out about as it would give the ability to create truly
> rich sound scapes with very little actual fiddling needed to get it right.
>  You'd just pass the model through your PAT calculation engine then play
> sounds and get them playing right.
>
> Any thoughts?
>
> Cheers!
>
> Oscar
>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Sprint
> What will you do first with EVO, the first 4G phone?
> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
> _______________________________________________
> GDAlgorithms-list mailing list
> GDA...@li...
> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
> Archives:
> http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
>

[Algorithms] Spherical harmonics for room acoustic modelling

[Oscar F. <os...@tr...>]

I will admit first off I don't have a great knowledge of things like
Pre-computed Radiance Transfer but I was having a chat with a colleague
recently on how audio research lags behind video research in gaming.

One idea that we were talking about is using spherical harmonics in a
similar way to PRT to do some sort of Pre-computed Acoustic Transfer.

Basically you'd add a new material type to a room that would give you the
sound reflectivity of a given surface.   You could then use the same
techniques (obviously calculated with something like OpenCL) to give you a
good model of how sound moves round a room.  Has anyone done anything like
this?

It kinda struck me that you'd be able to model things like acoustic
reflections off a hard surface, acoustic dispersion from soft surfaces as
well as getting things like occluders thrown in as a bonus.  Add to that you
could use the same techniques as are used for translucent surfaces to model
sound transfer through a surface and the slight bending of audio round
corners.

Are there any papers on the subject at all?  It struck me as something worth
finding more out about as it would give the ability to create truly rich
sound scapes with very little actual fiddling needed to get it right.  You'd
just pass the model through your PAT calculation engine then play sounds and
get them playing right.

Any thoughts?

Cheers!

Oscar

Re: [Algorithms] CRCs?

[Jon W. <jw...@gm...>]

Probabilistically, it makes not one iota of difference.

Same thing for secure hashes, btw. Consider "hash trees" as an application
of this axiom.

Sincerely,

jw


--
Americans might object: there is no way we would sacrifice our living
standards for the benefit of people in the rest of the world. Nevertheless,
whether we get there willingly or not, we shall soon have lower consumption
rates, because our present rates are unsustainable.



On Thu, Jul 15, 2010 at 4:13 PM, Oscar Forth <
os...@tr...> wrote:

> Furthermore for a specific set of cases it MIGHT improve things but
> averaged out it "ought" to make no difference but I would suspect it would
> make matters ever so slightly worse.  That is pure brain fart though so give
> it a burn and post up your results :)
>
>
> On 15 July 2010 23:17, Andy Farnell <pad...@ob...> wrote:
>
>>
>>
>> No. The length of the codeword improves the check.
>> Imagine a one bit CRC, (space allows only two
>> possibilities). No extension of domain will improve
>> the likelyhood of collisions in the range.
>>
>>
>>
>>
>> On Thu, 15 Jul 2010 14:12:24 -0700
>> Amir Ebrahimi <gd...@am...> wrote:
>>
>> > In other words, does the length of input improve the CRC?
>>
>> --
>> Andy Farnell <pad...@ob...>
>>
>>
>> ------------------------------------------------------------------------------
>> This SF.net email is sponsored by Sprint
>> What will you do first with EVO, the first 4G phone?
>> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
>> _______________________________________________
>> GDAlgorithms-list mailing list
>> GDA...@li...
>> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
>> Archives:
>> http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
>>
>
>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Sprint
> What will you do first with EVO, the first 4G phone?
> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
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> GDA...@li...
> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
> Archives:
> http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
>

Re: [Algorithms] CRCs?

[Oscar F. <os...@tr...>]

Furthermore for a specific set of cases it MIGHT improve things but averaged
out it "ought" to make no difference but I would suspect it would make
matters ever so slightly worse.  That is pure brain fart though so give it a
burn and post up your results :)

On 15 July 2010 23:17, Andy Farnell <pad...@ob...> wrote:

>
>
> No. The length of the codeword improves the check.
> Imagine a one bit CRC, (space allows only two
> possibilities). No extension of domain will improve
> the likelyhood of collisions in the range.
>
>
>
>
> On Thu, 15 Jul 2010 14:12:24 -0700
> Amir Ebrahimi <gd...@am...> wrote:
>
> > In other words, does the length of input improve the CRC?
>
> --
> Andy Farnell <pad...@ob...>
>
>
> ------------------------------------------------------------------------------
> This SF.net email is sponsored by Sprint
> What will you do first with EVO, the first 4G phone?
> Visit sprint.com/first -- http://p.sf.net/sfu/sprint-com-first
> _______________________________________________
> GDAlgorithms-list mailing list
> GDA...@li...
> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
> Archives:
> http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
>

Re: [Algorithms] CRCs?

[Andy F. <pad...@ob...>]

No. The length of the codeword improves the check.
Imagine a one bit CRC, (space allows only two 
possibilities). No extension of domain will improve
the likelyhood of collisions in the range.




On Thu, 15 Jul 2010 14:12:24 -0700
Amir Ebrahimi <gd...@am...> wrote:

> In other words, does the length of input improve the CRC?

-- 
Andy Farnell <pad...@ob...>

[Algorithms] CRCs?

[Amir E. <gd...@am...>]

For cumulative CRCs of files is it best to CRC the same bytes with a seed
(from previous CRCs) or is it okay to just CRC all of the file CRCs? If
that's cryptic, then maybe an example:

file1.ext
file2.ext

Would it make any difference between these two in terms of collisions?

file1_hash = CRC(file1.ext);
file2_hash = CRC(file2.ext);
cumulative_hash = CRC(file2.ext, file1_hash);

or

file1_hash = CRC(file1.ext);
file2_hash = CRC(file2.ext);

cumulative_hash = CRC(file1_hash.bytes + file2_hash.bytes);

In other words, does the length of input improve the CRC?

Thanks,
Amir

Re: [Algorithms] Algorithm for determining 'word difficulty'

[Binh N. <ng...@gm...>]

You can also use some online metrics:
+ Google News (syndicated of most common "news" + rank)
+ Number of hits per search


On Fri, Jun 18, 2010 at 2:12 PM, Matthew Harmon <ma...@ev...>wrote:

> As nice as "automatic" would be, I think if you are targeting very young
> kids you'll also want to add a "human tuned" metric to the weighting
> system.  As you've no doubt seen, each school grade level has a list of
> "sight words" that kids are supposed to know, as well as other common or
> high-frequency words that they are supposed to be picking up.  I'd guess
> this information is available somewhere/somehow - even if it means asking
> some teachers for help.  (For that matter, it's possible there are
> state-mandated lists of words that kids must know at different grade
> levels.)
>
> I'd guess that the younger the age target, the more "human tuned" the word
> selection is going to need to be.  As they get older, you can probably rely
> more on purely statistical metrics, etc.
>
> On Fri, Jun 18, 2010 at 12:18 PM, John Ratcliff <jra...@gm...
> > wrote:
>
>> I have an interesting little project I'm working on and I thought I would
>> solicit the list to see if anyone else has some ideas.
>>
>> I'm creating an educational word game that focuses on spelling and
>> vocabulary; it is designed to run on mobile devices (Ipad, Iphone, Droid,
>> etc.).  This is just a fun little side project I'm doing so my son can learn
>> more hands on programming.  My daughter is doing the artwork so we are
>> making it a little family project.
>>
>> I first wrote this game for an Apple II in 1983 so it's kind of fun to be
>> making a new version for today's devices.  Back then, I didn't have enough
>> memory to store a really large word list.  Today I have the ability to store
>> the entire English dictionary.  And, not just the words, but also every
>> component associated with each word (synonyms, etymology, definitions, etc.)
>>
>> The algorithm I am looking for is how to automatically come up with a
>> 'difficulty' metric for each word in the English language.
>>
>> My thoughts are that I could consider the following:
>>
>> (1) Length of the word, though to be honest very short words can be
>> difficult too if they are obscure.
>> (2) Number of definitions.
>> (3) Field of study of the word (biology, physics, etc.) The open source
>> English dictionary I have access to provides this data.
>> (4) Whether the word is a verb, noun, etc.
>> (5) Cross reference each word against a thesaurus and consider the
>> difficulty/obscurity based on how many synonyms and antonyms there are
>> total.
>>
>> One thing that would help immensely if if I had access to a word list of
>> the 'most common' words in the English language.  Hopefully I can find such
>> a list and this would provide me an excellent first guess at whether or not
>> a word is obscure or not.
>>
>> When you play the game you get to choose the difficulty level you want to
>> play at really could have two metrics.  Difficulty to spell, or difficulty
>> in terms of knowing recognizing the word.  (The game itself more or less
>> works like wheel or fortune or hangman, you are just trying to guess a
>> single word rather than a phrase).
>>
>> Any thoughts on an algorithm which could more or less automatically score
>> the entire English language by 'difficultly to spell' and 'difficulty to
>> recognize'?  Assuming you have as input all of the data in a standard
>> dictionary and thesaurus?
>>
>> Thanks,
>>
>> John
>>
>>
>> ------------------------------------------------------------------------------
>> ThinkGeek and WIRED's GeekDad team up for the Ultimate
>> GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
>> lucky parental unit.  See the prize list and enter to win:
>> http://p.sf.net/sfu/thinkgeek-promo
>> _______________________________________________
>> GDAlgorithms-list mailing list
>> GDA...@li...
>> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
>> Archives:
>> http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
>>
>
>
>
> ------------------------------------------------------------------------------
> ThinkGeek and WIRED's GeekDad team up for the Ultimate
> GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
> lucky parental unit.  See the prize list and enter to win:
> http://p.sf.net/sfu/thinkgeek-promo
> _______________________________________________
> GDAlgorithms-list mailing list
> GDA...@li...
> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
> Archives:
> http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
>



-- 
--------------------------------------------------
Binh Nguyen
Computer Science Department
Rensselaer Polytechnic Institute
Troy, NY, 12180
--------------------------------------------------

Re: [Algorithms] Algorithm for determining 'word difficulty'

[Matthew H. <ma...@ev...>]

As nice as "automatic" would be, I think if you are targeting very young
kids you'll also want to add a "human tuned" metric to the weighting
system.  As you've no doubt seen, each school grade level has a list of
"sight words" that kids are supposed to know, as well as other common or
high-frequency words that they are supposed to be picking up.  I'd guess
this information is available somewhere/somehow - even if it means asking
some teachers for help.  (For that matter, it's possible there are
state-mandated lists of words that kids must know at different grade
levels.)

I'd guess that the younger the age target, the more "human tuned" the word
selection is going to need to be.  As they get older, you can probably rely
more on purely statistical metrics, etc.

On Fri, Jun 18, 2010 at 12:18 PM, John Ratcliff
<jra...@gm...>wrote:

> I have an interesting little project I'm working on and I thought I would
> solicit the list to see if anyone else has some ideas.
>
> I'm creating an educational word game that focuses on spelling and
> vocabulary; it is designed to run on mobile devices (Ipad, Iphone, Droid,
> etc.).  This is just a fun little side project I'm doing so my son can learn
> more hands on programming.  My daughter is doing the artwork so we are
> making it a little family project.
>
> I first wrote this game for an Apple II in 1983 so it's kind of fun to be
> making a new version for today's devices.  Back then, I didn't have enough
> memory to store a really large word list.  Today I have the ability to store
> the entire English dictionary.  And, not just the words, but also every
> component associated with each word (synonyms, etymology, definitions, etc.)
>
> The algorithm I am looking for is how to automatically come up with a
> 'difficulty' metric for each word in the English language.
>
> My thoughts are that I could consider the following:
>
> (1) Length of the word, though to be honest very short words can be
> difficult too if they are obscure.
> (2) Number of definitions.
> (3) Field of study of the word (biology, physics, etc.) The open source
> English dictionary I have access to provides this data.
> (4) Whether the word is a verb, noun, etc.
> (5) Cross reference each word against a thesaurus and consider the
> difficulty/obscurity based on how many synonyms and antonyms there are
> total.
>
> One thing that would help immensely if if I had access to a word list of
> the 'most common' words in the English language.  Hopefully I can find such
> a list and this would provide me an excellent first guess at whether or not
> a word is obscure or not.
>
> When you play the game you get to choose the difficulty level you want to
> play at really could have two metrics.  Difficulty to spell, or difficulty
> in terms of knowing recognizing the word.  (The game itself more or less
> works like wheel or fortune or hangman, you are just trying to guess a
> single word rather than a phrase).
>
> Any thoughts on an algorithm which could more or less automatically score
> the entire English language by 'difficultly to spell' and 'difficulty to
> recognize'?  Assuming you have as input all of the data in a standard
> dictionary and thesaurus?
>
> Thanks,
>
> John
>
>
> ------------------------------------------------------------------------------
> ThinkGeek and WIRED's GeekDad team up for the Ultimate
> GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
> lucky parental unit.  See the prize list and enter to win:
> http://p.sf.net/sfu/thinkgeek-promo
> _______________________________________________
> GDAlgorithms-list mailing list
> GDA...@li...
> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
> Archives:
> http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
>

Re: [Algorithms] Algorithm for determining 'word difficulty'

[Samuel M. <sam...@go...>]

I think a really good metric for difficulty would be how often other
people spell this particular word wrong. So you could take a lot of
text that *includes misspelled words* and count the odds. Public
forums or other websites would be perfect. You can even pick your
target group ;)

The difficulty here is to find out what word was actually meant by a
misspelled one. But on the other hand, just take any reasonable metric
for distance between words (there should be literature on that
regarding automatic spell correction) and assume the closest one (or
the N closest words that are not too far away) was meant.

Maybe you could also use google... generate a few variations on each
word and count the number of google results ;)

Greets,
Samuel

On Fri, Jun 18, 2010 at 7:35 PM, jhorton <jh...@ro...> wrote:
> My daughter has brought home dozens of books at various difficulty levels from the school. I'm sure you could search for things like grade 1 word lists and so on. Scholastic books mostly it seems.
>
>
> On Fri, Jun 18, 2010 at 12:18:14PM -0500, John Ratcliff wrote:
>> I have an interesting little project I'm working on and I thought I would
>> solicit the list to see if anyone else has some ideas.
>>
>> I'm creating an educational word game that focuses on spelling and
>> vocabulary; it is designed to run on mobile devices (Ipad, Iphone, Droid,
>> etc.).  This is just a fun little side project I'm doing so my son can learn
>> more hands on programming.  My daughter is doing the artwork so we are
>> making it a little family project.
>>
>> I first wrote this game for an Apple II in 1983 so it's kind of fun to be
>> making a new version for today's devices.  Back then, I didn't have enough
>> memory to store a really large word list.  Today I have the ability to store
>> the entire English dictionary.  And, not just the words, but also every
>> component associated with each word (synonyms, etymology, definitions, etc.)
>>
>> The algorithm I am looking for is how to automatically come up with a
>> 'difficulty' metric for each word in the English language.
>>
>> My thoughts are that I could consider the following:
>>
>> (1) Length of the word, though to be honest very short words can be
>> difficult too if they are obscure.
>> (2) Number of definitions.
>> (3) Field of study of the word (biology, physics, etc.) The open source
>> English dictionary I have access to provides this data.
>> (4) Whether the word is a verb, noun, etc.
>> (5) Cross reference each word against a thesaurus and consider the
>> difficulty/obscurity based on how many synonyms and antonyms there are
>> total.
>>
>> One thing that would help immensely if if I had access to a word list of the
>> 'most common' words in the English language.  Hopefully I can find such a
>> list and this would provide me an excellent first guess at whether or not a
>> word is obscure or not.
>>
>> When you play the game you get to choose the difficulty level you want to
>> play at really could have two metrics.  Difficulty to spell, or difficulty
>> in terms of knowing recognizing the word.  (The game itself more or less
>> works like wheel or fortune or hangman, you are just trying to guess a
>> single word rather than a phrase).
>>
>> Any thoughts on an algorithm which could more or less automatically score
>> the entire English language by 'difficultly to spell' and 'difficulty to
>> recognize'?  Assuming you have as input all of the data in a standard
>> dictionary and thesaurus?
>>
>> Thanks,
>>
>> John
>
>> ------------------------------------------------------------------------------
>> ThinkGeek and WIRED's GeekDad team up for the Ultimate
>> GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
>> lucky parental unit.  See the prize list and enter to win:
>> http://p.sf.net/sfu/thinkgeek-promo
>
>> _______________________________________________
>> GDAlgorithms-list mailing list
>> GDA...@li...
>> https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
>> Archives:
>> http://sourceforge.net/mailarchive/forum.php?forum_name=gdalgorithms-list
>
>
> ------------------------------------------------------------------------------
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> GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
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Re: [Algorithms] Algorithm for determining 'word difficulty'

[jhorton <jh...@ro...>]

My daughter has brought home dozens of books at various difficulty levels from the school. I'm sure you could search for things like grade 1 word lists and so on. Scholastic books mostly it seems.


On Fri, Jun 18, 2010 at 12:18:14PM -0500, John Ratcliff wrote:
> I have an interesting little project I'm working on and I thought I would
> solicit the list to see if anyone else has some ideas.
> 
> I'm creating an educational word game that focuses on spelling and
> vocabulary; it is designed to run on mobile devices (Ipad, Iphone, Droid,
> etc.).  This is just a fun little side project I'm doing so my son can learn
> more hands on programming.  My daughter is doing the artwork so we are
> making it a little family project.
> 
> I first wrote this game for an Apple II in 1983 so it's kind of fun to be
> making a new version for today's devices.  Back then, I didn't have enough
> memory to store a really large word list.  Today I have the ability to store
> the entire English dictionary.  And, not just the words, but also every
> component associated with each word (synonyms, etymology, definitions, etc.)
> 
> The algorithm I am looking for is how to automatically come up with a
> 'difficulty' metric for each word in the English language.
> 
> My thoughts are that I could consider the following:
> 
> (1) Length of the word, though to be honest very short words can be
> difficult too if they are obscure.
> (2) Number of definitions.
> (3) Field of study of the word (biology, physics, etc.) The open source
> English dictionary I have access to provides this data.
> (4) Whether the word is a verb, noun, etc.
> (5) Cross reference each word against a thesaurus and consider the
> difficulty/obscurity based on how many synonyms and antonyms there are
> total.
> 
> One thing that would help immensely if if I had access to a word list of the
> 'most common' words in the English language.  Hopefully I can find such a
> list and this would provide me an excellent first guess at whether or not a
> word is obscure or not.
> 
> When you play the game you get to choose the difficulty level you want to
> play at really could have two metrics.  Difficulty to spell, or difficulty
> in terms of knowing recognizing the word.  (The game itself more or less
> works like wheel or fortune or hangman, you are just trying to guess a
> single word rather than a phrase).
> 
> Any thoughts on an algorithm which could more or less automatically score
> the entire English language by 'difficultly to spell' and 'difficulty to
> recognize'?  Assuming you have as input all of the data in a standard
> dictionary and thesaurus?
> 
> Thanks,
> 
> John

> ------------------------------------------------------------------------------
> ThinkGeek and WIRED's GeekDad team up for the Ultimate 
> GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the 
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Re: [Algorithms] Algorithm for determining 'word difficulty'

[Conor S. <bor...@ya...>]

For difficulty, I would say put in a load of very "common" language texts, then some more technical and advanced texts (even some philology) and then use a differential histogram between the two to pick out more difficult words. Language in the brain is a contextual hierarchy... the brain pattern matches based on the right context. As such more difficult words are generally those with a more difficult context.

Cheers,
Conor 
  



________________________________
From: Jeff Russell <je...@8m...>
To: Game Development Algorithms <gda...@li...>
Sent: Sat, 19 June, 2010 1:26:45 AM
Subject: Re: [Algorithms] Algorithm for determining 'word difficulty'

My thought was the same as yours as far as the frequency of use entering into it. If you can't find any good data on that, it might not be hard to generate it if you have a good deal of text on hand. Run a number of novels or something through some simple app that tracks word frequencies, and you might have the start to a database at least.

Jeff


On Fri, Jun 18, 2010 at 12:18 PM, John Ratcliff <jra...@gm...> wrote:

>
>I have an interesting little project I'm working on and I thought I would solicit the list to see if anyone else has some ideas.
>
>I'm creating an educational word game that focuses on spelling and vocabulary; it is designed to run on mobile devices (Ipad, Iphone, Droid, etc.).  This is just a fun little side project I'm doing so my son can learn more hands on programming.  My daughter is doing the artwork so we are making it a little family project.
>
>I first wrote this game for an Apple II in 1983 so it's kind of fun to be making a new version for today's devices.  Back then, I didn't have enough memory to store a really large word list.  Today I have the ability to store the entire English dictionary.  And, not just the words, but also every component associated with each word (synonyms, etymology, definitions, etc.)
>
>The algorithm I am looking for is how to automatically come up with a 'difficulty' metric for each word in the English language.
>
>My thoughts are that I could consider the following:
>
>(1) Length of the word, though to be honest very short words can be difficult too if they are obscure.
>>
>
>(2) Number of definitions.
>(3) Field of study of the word (biology, physics, etc.) The open source English dictionary I have access to provides this data.
>(4) Whether the word is a verb, noun, etc.
>(5) Cross reference each word against a thesaurus and consider the difficulty/obscurity based on how many synonyms and antonyms there are total.
>
>One thing that would help immensely if if I had access to a word list of the 'most common' words in the English language.  Hopefully I can find such a list and this would provide me an excellent first guess at whether or not a word is obscure or not.
>
>When you play the game you get to choose the difficulty level you want to play at really could have two metrics.  Difficulty to spell, or difficulty in terms of knowing recognizing the word.  (The game itself more or less works like wheel or fortune or hangman, you are just trying to guess a single word rather than a phrase).
>
>Any thoughts on an algorithm which could more or less automatically score the entire English language by 'difficultly to spell' and 'difficulty to recognize'?  Assuming you have as input all of the data in a standard dictionary and thesaurus?
>
>Thanks,
>
>John
>
>------------------------------------------------------------------------------
>>ThinkGeek and WIRED's GeekDad team up for the Ultimate
>>GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
>>lucky parental unit.  See the prize list and enter to win:
>http://p.sf.net/sfu/thinkgeek-promo
>_______________________________________________
>>GDAlgorithms-list mailing list
>GDA...@li...
>https://lists.sourceforge.net/lists/listinfo/gdalgorithms-list
>>Archives:
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>


-- 
Jeff Russell
Engineer, 8monkey Labs
www.8monkeylabs.com