Theo Verelst Local Diary Page 42

I've ditched the usual header for the moment, I think it doesn't help much anyhow.
This page is copyrighted by me, and may be read and transfered by any means only as a whole and including the references to me. I guess thats normal.

Home (alt)   Tripod Home   Local Diary list   Tripod Diary List   Previous Diary

  Sun Nov 4 11:29,  2007


math example

Astrophysics is just a smile on a dog? Nope, not when done right maybe more the light in a fog idea (thanks to Edie Brickell for the lyrics) How the hell are we going to know for sure what is out there. We can see probably only a tiny corner of the Universe of God (or what is it?) and are already deciding on how it all works, while we don´t even know exactly for sure where all the deep see creatures come from.

We´ve been to only the closest stellar body ourselves, how would we know what the rest is all like? I prefer Star Trek ORIGINAL SERIES over most other views on the subject, and who wouldn´t. In the words of a fortune cookie I just saw:

   Some parts of the past must be preserved, and some of the future prevented at all costs.

Anyhow because I looked at the princeton astrophysics departments pages I thought about the subject and I did some math which on itself had nothing to do necessarily with astronomy, more like that I was playing around with maxima, and in fact wxMaxima, which is currently available both for linux and windows XP and has formulas in prettyprint in realtime.

plot2d([1/(1+x^3), integrate(1/(1+x^3),x)],[x,-2,10],[y,-10,10]);

   Graphs of the 1/(1+x^3) mathematical function and of it's formal integral (for x>-1).

To compute the Taylor expression till the hundredth degree, reformulating the result to a rectangular form (using a+b.i instead of A exp(i.phi), needed for the constant term), the taylor command is used:

rectform(taylor(-log(x^2-x+1)/6+atan((2*x-1)/sqrt(3))/sqrt(3)+log(x+1)/3, x, 0, 100));

A neat repeating Taylor pattern appearently, though of course this is no proof of infinite repetition, maybe Maxima could be programmed with a proof method for that, though I am not sure that is easy or even possibly in general. Lets subtract the formal solution of the integral (with the integrate command that is made very easy for us, it´s on the Maxima example page) as to compute the error of the Taylor expansion of the integral compared to the integral itself:




Now we can show a graph which plots the absolute error, after setting the function f(x) to the real integral, and the function ft100(x) to the taylor expansion of the same:


   The result of subtracting the taylor approximation from the actual integral, so the error.

Pretty good around 0, the approximation point, less than a millionth error up to about plus or minus 0.9 .

For those interested in these mathematical considerations or who'd like to try for themselves using the open source and free wxMaxima, there are html recordings of some sessions of mine and maxima readable session recordings here (look in /1 or /2).

separation  filters

   The high quality active filter bank as a quickly made prototype circuit board with shielded wire inputs/outputs.

that´s a secret! Not a big one, the general data is known, but the specifics are not open source at the moment! In essence, the signal path is straight with only normal opamp amplication/buffering stages with no capacitors in the feedback loop (no Sallen and Key) and extremely good parts (TI/Burr Brown OPA627 chips, about $20 a piece)

  On the left the toroid transformer, mid top the pre amp chips, mid low the filter, on the back the isolated jack connectors.

Well, just to tease a bit more and less, the original diagram for the filters which have for a fast prototype been placed in the sythesizer enclosure which had suffciently many jack IOs and a well stabelized supply unit with toroid transformer and the main buffer preamp with equally good OPA627 opamps already in place:

   Filter bank design schemstics with part values wiped.

Clearly, I´ve made the filter component values unreadable. Remember, the prototype was made in 4 days, including the new double power amplifier (middle enclosure above) to be used on the MILE 2006 trade show where it all worked brilliantly!

The top filter filters everything outside the 4-8kHz band, with extra lowcut filtering and buffer before the output to the powe amplifier. The middle schematic feeds the sub woofer amplifier, which is used in bridge mode, hence the high quality phase inverter. Its filters are second order with a high cutoff frequency of 40 Herz, so everything above 40 Hz is filtered of with 12dB/otave (no typos here fourty Herz low pass, second order). In fact, there are no seperation capacitors in this filter signal path to add transients or couse low roll-offs interfering with the passing of this very low frequency range, it is all DC coupled!

The bottom filter, also with output buffering of two $20 US imported Burr Brown / Texas Instuments super audio opamps (inverting the phase, which is corrected at the speaker output of the main amp) has a dip in the 4-8 kHz range, while there is a low-cut under 40Hz by use of coupling capacitors, I think they are not on the schematics, I´ll need to check the circuit board I made one day to get the actual circuit and values of that part.

   From the OPA627 datasheet.

Very good figures, ad this is a general measurement, not some specially setup flattered testbench, and mind the amplitude and the loading impedance for these figures, the GBW product is 16MHz. My loading impedances apart from controlling the end amplifier input when it would shortly surge or ground surge, are quite higher, for all frequencies.

The Bible is about music

Because the housers will take over the world ? No, rather the converse.

That´s a daring thesis about the main meanings of the presumably inspired books of the bible, lets start with the new testament, so that the history of music and the meaning of it in life would take on the prime rol it practically often has, as far as I can oversee, especially in the good times.

Thinkingwise that for me would have to do with the observation that most buildings in life and it´s existence the last centuries even are maybe interesting and advanced but never even get close to the real good music from lets say rock and roll onward, with the top during the 70s, nothing really gets close to the life and it´s wellness that came (?) from the music and speaks from the music.

I wouldn´t think there is anything at all which compares to the art and emotional and peoples acceptance magnitude and relevance which is associated with the time era and it´s ongoings and it´s richness in music. Of course that is a profound observation, but good and daring thinking for people who know the time a bit and some of the music even will in my opinion lead to no other honest answers.

How can it be that 10 seconds of woodstock can change more in human thinking than two decades of misery? Probably because the Good Music has to do with the essentials of life and human life and eventually with the Divine. It would of course depend on what one believes in to make clear how that is, and what that means, would it means something

         Bob Moog on "Moog, a documentary film by Hans Fjellestad" (DVD Plexifilm 18)
         "I´ll tell you where I think it comes from,

         I think it comes from out there, you know, and it comes through me,
         into the instrument.
         And then the music comes through you guys in the instrument" ...

What is that, an Amen brother ? No it speaks about where the things come from which are valueable, which is through stars, in this case one in electronics (the late Dr. Bob Moog), and one in music (Rick Wakeman), and it is not unlikely to think about God being somehow in the picture, especially when it is a profoundly interesting one, which is probably more like intelligent design than randomness and stupid rules and some unworthy struggle.

Wakeman: "Moog´s given us an instrument with an X factor, and if you´re trying to find out what the X factor is you´re wasting your time, just be thankfull it´s there!"

Well, it seems reasonable looking at the roots and ongoings in bigtime historical music like the ancient Jews (See book of psalms of David for instance), the greeks (names of notes and scale and chord mathematics), and the christians, especially from the renaissance onward (dass woltempiertes klavier, Bach) including the great hymns and mainly protestant progessions in music including orchestras and more recent piano and of course the whole of amplified and recorded music that regardless of an X factor music has developed quite a bit.

Server failure

I had that once recently, when I´d used old Fedora Core 4 library files with Cinelerra to work on FC6 and had filled the whole main memory with either HD video or had loaded the machine completely with a complex multiband audio decompression processing problem to run in real time as root process, and the machine became too slow and then I also changed the monitor to a projector (connected over DVI), I reset the machine when something had gone wrong, and then probably while the kernel was still booting, I reset again. Major oops, the kernel didn´t start up anymore!!!

So I first reset again (alt control delete don´t work) and selected Fedora Core 6 / 64 to boot up using the grub menu, and luckily that worked fine, no problems, no major user files gone, no problems with the external discs, every started up normal.

That allowed me to asses what had happened, by trying the faulty F7 again I saw there was a lib file missing according to the kernel startup message. Because by and large the file system seemed fairly intact, which I could easily check on FC6 by mounting the F7 partition, I hoped the damage would be repairable, so I ran extfsck to check it out, and foudn out major messes here and there, but as it seemed only with files related to certain kernel activity, a number of system library files, some configation files, even one of the passwd files...

Well, that was annoying, I could of course run 6 again, and adjusted the grub auto startup accordingly, but I have these new Ingenuity and other synthesis tools to work with, which wouldn´t work good on 6 (even though I compiled them there) and I had a lot of things set up to work, from mpeg2 TV watching to all kinds of packages.

Not knowing what better to come with, I though I´d try to asses what went wrong if I could, and restore the missing files somehow. So I ran ext3fsck (or is that ext2fsck ?) to correct the file system, and I hope maybe to restore files from the journal or so, but it only threw away some 30 files because they were corrupted, and succesfully corrected the directory structure without loosing major parts of the file hierarchy, but those system files were gone, maybe because they were open during unjournalled kernel startup and a glitch occurred, I don´t know, I NEVER have had any file problem on the system or another recent  linux system before.

Linux Fsck had made a list of nodes with associated file names which were corrupted and missing, so I just though I´d get the files anew, in this case by going into the fedora mirrors and get them in rpm form from it, and hand extracting and replacing the right file from the archive to the proper disk location, finding out which rpms I´d need by name association, or often through google...

Installation files I could luckily copy from FC6 as far as they were affected, and so ofter a half a day work or so I could try to start the F7 system up again, and voila! With some more tweeks and edits the whole system was running again, and is still now, as it seems without error thus far, and is currently holding this file and runs the server used to bring it to the world!

The server has run for, what is it, years already, 24/7 ALL the time, even with the same harddisk (being a nice 33 degrees Celcius), first with FC5, then 6, now 7 (with an 8 kernel I think), without ANY error, and of course there was a direct reason things went wrong, maybe the cable exchange create an electrical hickup, I don´t know.

mini powered speakers

   Parts and some tools for the powered small stereo speakers.

   A bit more neatly arranged the parts could look like a good-part kit (most, not all parts).

   Testing the to be powered portable stereo box by watching TV with them, and playing music.

Mixer remote control

No, really, I mean it, I want a small unit, maybe I´ll craft another one like this

   The little volume control that because it is passive doesn't really distort, and the tek based passive mixer.

from aluminium, but bigger, with some knobs or faders, and with some form of display on it, probably rechargable, or as prototype some simple equivalent setup, and it will connect to the ethernet connected, Linux running ANALOG signal path audio mixer to remotely change the volumes of channels, from a good chair or a bench or anywhere in a place.

The first requirement after having the extremely high quality mixer prototype is a wireless link which is up to some standard of connectivity goodness, in this case I plan to further use the parts from this TI development kit:

   The Texas Instruments wireless microcontroller devkit with a testpot.

   The editor/compiler/loader/debuger environment for the microcontrollers, which works fast and good and reliable.

The mixer is progressing to contain these types of channel electronics and circuit board layout, where the gold plated connectors (a bit like in model aircrafts) can be rewired according to the desires of the mixer unit user:

   A strip with 8 mixer (4x2) channels with patchable connections in buildup, one stereo channel is finished.

the front left two connectors are the left and right input for one stereo mixer channel. Mind that the TI/Burr Brown chips being used will be individualy supply ripple suppressed, have a very strong ground connection in between, will be seperately shielded from the digital electronics (FPGA, LED dot display and FOX linux board) inside the single unit high 19 inch rack mount enclosure, and are in this part of the prototype made of  (expensive, but I received these free samples in the past) A-grade components, which have even lower distortion than the already world top class volume control chips normally have.

Also, the supply well stabalized  and comes from a toroid transformer only, meaning the analog electronics are not connected or ground disturbed by a switched supply and cannot pick up EM interference from it, and further analog amplification will come from the worlds´ best audio opamps, the OPA 627, which has been very successfully applied in the active analog multi amplification setup refered to above, which is also expensive (well, about $20 per channel), but at least it was easy to quickly get it from Newark in One (New Jersey) over UPS or so internet order. It is a crying shame that importing these precious parts into europe costs extra money, I don´t know what the hell the justification for that could really be.

Some time ago I made this animated gif from the prototype mixer enclosure:

      The mixer enclosure with all electronics in a single height 19* rackunit

At the moment this has one stereo channel with supply under the control of a Spartan 3 fpga with one SPI bus output I made with it, which is also driving the display (not finished, but all elements light up) over a Coolrunner-2 CPLD, and received commands from a FOX Linux board over a 10 kilobytes per second (about) serial connection, and shows the current mixer (single channel) volume setting on its own 7 segment displays (in HEX), while the FOX board connects over the (left side on the back) ethernet connector with an ethernet cable to a standard router (the local network), and runs a tcl script which communicates with another tcl/tk script somewhere on a random computer on the network (Windows or Linux alike) and sets the volume via the serial link with the FPGA (four settings currently). The whole starts up automatically, and the FOX board has linux and its web server and the main tcl script running in 5 seconds or so.

San Jose

Never been there.... Well, actually I´ve not even been in the US myself, phsysically. Really never. I long ago already immigrating if I could, but that was another story, which everybody I knew at the time (mainly but not only in Holland) and well, I wanted to work in San Francisco area for a few years to see how that would be, but didn´t make it happen.

So, life´s so good now I forgot all about it? Well, I don´t even have my own income at the moment, so I guess there must be other reasons to be stuck in the country I was unfortunately born in... I graduated from technical university (network theory) in ´91 and at the time really felt like following the example of two alumni of the very same section where I graduated and work at Hewlett Packard, in Bay Area, but I didn´t get the references and leads I wanted, so instead I worked for that section for a number of years after having been invited there and having been offered a decent engineer salary (being 25 at the time).

But no America! And I would have loved to go! But anyhow, I was very influenced by the major american lines in my work and main hobbies like music and film and if it wouldn´t have been for Audi I probably should have driven an american car.

I was a kid in the 70´s and remember all to well how positively influenced I was by All The Good 70s films and tv, and especially the atmosphere I associate with San Jose. Dirty Harry (SF)  was cool, too, but more advanced, just like the million doller man and such. I think I never even considered many things European, though I know an amount of happiness is possible is Paris or Londen, and some other places, to be actually something I´d actively want to take part in, as a citizen with self-originating joy the vivre or so. Really. Not nice to say or to have to say, but after the 70s were over not many things enjoyable remained I thought, and in holland of all places aspecially I never felt many things became me good, before thinking about the very strong evils which must have gone on even. So "its´s dreadfull I want to get out" or so ? In a way I found that long ago already as in that the persuit of happiness was virtually impossible even though I did have more than enough things going on and was making it more than enough. And things got nice and better now? Gmpf. Well, hopefully certain evils like physical abuse and satanism are better in terms of more absent, also because Theo just wouldn´t go in that and won´t shut up, so cool, for eveybody else.... Nah, maybe for me too, but no things are loads more dreadfull than when at least I was doing more than a few ok things. Because I quit/left just before getting my PhD? Nah, I didn´t care in that way I just hoped that would get me a good american job....

So hopeless and void? Heavens no, absolutely not void, and even alive and kicking or so. But the country I was born in can´t claim that they´re ok leaders or have dealt with me even remotely ok enough to continue, and would with the right wing conservative, jesuit led, miserable christian hypocrite motherf*ng party "at the rudder" want to lead the whole world as if they have a big mouth and facts to support their leadership enough. Meanwhile every body knows what type of capital of the world Amsterdam is supposed to be, and around every other corner there´s a dutroux kind of character, or something. Devastating.

So I looked up good things and help my fellow human beings? Well sort of, but not only that of course, first I need to think myself right like everybody else should, which is hard, but I only stop at a good level if I can help it, and than bay area, even apart from the obvious electronics connection seems absolutely great to me. Another guy graduating in about the same time from my section went more north, to MegaHard in Seatle and never doubted for a second the value of going across the ocean, even though his going north was in my opinion quite exagerated, up till Suasalito would seem just about perfect to live for me.

So, I´m an engineer, I can make money, right? Well, wrong, go ask my or your mother or so is probably the problem area, and that I refused to become a catholic layman and whore for rome and it´s own a good second reason that that ceased working. Nah, I´m just not good enough! That´s gotta be it. Hm ego bashing, that´s been tried for half a dcade long ago already mother, I don´t fall for that. Probably I´m too good! Perfect! I hear some people say, than we were right to drive him aside! Arrrggg, that really *is* holland. Grrrrrr.

Unfortunately, the problems have not been away from the United States, as I also obseverd when last year I entered a paper for Siggraph (the world´s most prestigeous computer graphics conference) , where I was treated so wrong by the reviewers I found it hard to believe, but I´m sure there are many considerations possible.

Anyhow, I like Campbell soup, audio-visual and other types of products from the area, and thus far generally the people from the west of the us very well, so at least I have no problem formulating where I (still, evidently) would want to go to live, and usually one then needs to work...

So, so Los Angeles in the picture? Well I happen recently to have spoken with two people from the area, and of course that is western CA too, but no, that city has not the same appeal, I must say. Because that´s the place where the little devils with 3 fold pokers come from and where all hell may live freely? No. That´s another place.

The following pictures under this heading are NOT mine!

    A graet looking San Jase house (image creative commons licence free from wikipedia)

    San Jose, south area.



I got this example from a housing site about San Jose area, which looks great

I made the painting unrecognisable, and hope these small examples are fair use, the point is that I am sure there are people who would like to suggest I might best like to live in the dutch dryland and really have no standards I´d like to match up to. Sjeez. I love the above, looks like being right back in the 70s when the sun shone better and when the new age wasn´t shining where the sun never would. I´d feel more at home then I most of the time have felt, I´m sure.

These are small frames from the student movie competition from I think Bay area contestants, great little movies, made in a week only:

Nice works, with vrying levels of professionality, but it seems all relevant and not boring.

The New Communicator is out !

Yeah, great. Star Trek in actuality, I vividly remember walking back from school with other boys and girls like in 72 or so and mimicing Spock or even Kirk while flapping open a virtual communicator! And now it is here, sorta.


Well, I did check out the demo model with the chain, without battery so to speak, and it looks nice and usable, I guess there will be space for inbetween phone and small notebook size devices, and some complain already the E90 is too big to handle, but it looks cool. And with all time on internet on it, it can even dim the lights and control my mixer! Hopefully the wireless connections are better then I´ve experienced with some more modest wireless phones, where not working and strangeness seemed to be almost common situations, and reliability not exactly all the time.

And I don´t like all those high frequency digital radiation sources myself very much, so I should not want to use those extreme internet speeds maybe, and propagat neat connections with good controlled radiation, but that´s hard, even to communicate. Before you know it you´d have to tell some guys and girls who seem to really want to sacrifice themselves to the high frequency airwaves they can´t even get that.

Anymore electronics, would you?

Sure (sounding like one of the Blues Brothers)! Why, HD is telling you of course that´s above your level, and those numbers of pixels and bits per secon just couldn´t work right, of course, all those speakers and amps (13 speakers, 10 amp channels) you use for surround sound experience principally can´t be managed right by you a terabyte cannot possibly be filled by such a dull person, and you know now modern music just isn´t your thing because that´s soooo incredibly sophisticated!

Uhr, no. I love to ´film´ and view HD (which is hard), a beamer can´t be too many pixels and lumens and linearity (/exponentiality), I´d want even more channels and amplifiers, though at the moment they don´t need to be louder for my normal purposes (one cannot and need not put a thousand watts to work in a normal living room environment), I want more AD/DA converters of top quality and loads of processing and internet power, and graphics horsepower and disk space and all such things haven´t even begun to show their end or the total fullfillment of their possibilities, even remotely.

So I can easily make an electronics wishlist or menu containing many interesting and expensive or advanced (or both) machines and machine parts to honour the more electronics is often beautiful paradigm:

   Ultra HD recording, viewing, processing
like 4 times more horizontal and vertical resolution of 1080 HD .... Cool! I saw that on last years Ibc conference being demonstrated on a big screen by I think a japanese company. Let that get there where it is good enough to compete with good (65 mm) analog film! For the moment, I´ll settle for a big red or equivalent 4k camera, preferably with good grade lenses to experiment with.

   A big set of High speed, low latency AD/DA converters with connected big and fast programmable FPGA
to do processing for audio effects and synthesis at at least superaudio CD quality with small latency (to have good live and playing comfort, see also heading about live digital audio processing). And a good programming system which at least can compete with a good breadboard.

   Some array (..) of 10gigabit connected Q6600 machines with 1.3GHz bus speed and memory to match it, graphics cards like NV8800s or maybe a variation which can encode a nice HD format with good quality in hardware, and preferably fitted with a big Virtex-5 connected over PCI-eXpress, running Fedora 8/64 with running and working nasd distributed sound server.

   An extremely fast electrical car with electronics to handle! And my own field with solar arrays to charge it!

   High speed world wide directed satellite internet with low radiation and pocket-sized... For the moment a nokia with good (open source ?) devkit and 24/7 internet looks great (they´re not here yet, really, but I did hold one, and internet can be bought fairly cheap per month, at least.

   Join Hawking in space or use the american moon base as science and music office annex space webcam.

   Make the quarks give it up both at Cern and in other particle labs and join the sane and mathematically unchallenged scientists in the field.

   Yellowjackets featuring Mike Stern, ah, this one´s taken care of! Me doing a fusion (or rock ?) tour in the us, yeah.

Next thing you know I´d have to talk to solar particle beams...
And that they follow the rules of Network Theory, wink wink.

Live digital audio processing

Is that worth a heading, isn´t that what ´everybody´ is doing ? I though about the problem long before that was normal enough because there are problems associated with the idea, which are showing up extremely clearly in this time and in modern ´music´ exactly like I thought.

Three main problems are: quantizing the signal sounds bad over the feedback, even at 24 bit it´s hard to get the whole loop to sound good, DA converters require reconstruction filters, even at 192kS/s, which take a quite non-negligable total delay time to perform right (note the italics) it might even take seconds of delay for a perfectly good filter which treats the samples right over the whole dynamic range and shows not too many phase and group delay problems, and hardly this is properly mentioned, and finally, the processing inthe digital domain also takes some delay, and when the correct anti-aliasing is included, a lot of work to do right.

And even if the dsp algorithms are considered cool, and the delay is bearable, then the idea of interacting with the sound could be just as unreliable as having to start Windows again during a performance, of course... And often the parameters which are settable are very coursely quantized, not nearly as accurate as for instance an analog equalizer or other effect, and the noise and all kinds of processing artifacts (downsampling gives either aliasing or filter phase problems when the input bandwidth of the AD is fully used guys, no way around it) which build up in the digital domain can sound even nastier than common electronics hiss and hum.

So , no fun to do digital signal processing with Theo? Hah, no, of course not, I was probably using DSP extensively before a lot of the new age music population was born! And then I built my own AD and DA converters and filters and iFFTs and other software, and that was years before I went to university to enjoy the privilege of after three retries with a 4, 5 and again a 5 to drop a particular DSP course and replace it with another course of choice. Man, that sucked, I had 9´s on my endlist, and not for the least courses, I didn´t need that sh*t.

Anyhow years before that I used a Ibanez DM500 and a Korg Poly 800 with digital delay extensively and played various types of more or less digital synthesizers/keyboards, one I built myself even, so no I think I can make great fun with analog and/or digital signal processing, but I´m not going to believe in new age hype, no sir, not me. Sorry. In fact I thougt it was great to use a very important machine with for the time totally hard and advanced DSP in it, even at considerable quality: the Yamaha Dx-7 to which I owned the circuit diagram and service manual and had studied, also by looking up what a Bessel transform is in radio transmission theoretical science books in the university library, and that quite before that particular dreaded university course.

I knew in practice what mixing and FM modulation and envelopes sounded like on a good monitoring system, and loved it, before I would need to believe from some pencilpusher that FFTs are the world. I knew that wasn´t the case. Thrilling science isn´t the target in the lowlands, but the popular thoughts of normal audio and music people shouldn´t be so confused as they appear to be on several subjects, especially when there is no need to consider them my enemies (and of course I know there are people who in some sense are).

A fft in the signal path can work transparent (but with delay)  in only exactly one instance: a straight fft with enough intermediate computation bit width followed by a straight ifft (inverse fast fourier transform), which will within the accuracies incurred by rounding, give the original samples back.

Everything else has problems or ´hidden´ inaccuracies in it, unless it is simple or retarded musical material (wink wink). That has to do with the accurcay of the frequency analysis, the assumption for a good FFT that the signal is of constance wave shape of which the repetition ratio preferably should be the same as the fft bucket size, and it is hopeless to treat anything with noticable transients with an fft.

Problems? Well, first of all most fft frequency picture are hopelessly shift variant (if you have education in the direction you ought to know what that theoretically means), and the frequency graphs are either or both hopelessly slow and/or plenty of harmonics are visible only because the analysis interval doesn´t or even cannot (for cords) coincide with a multiple of the base harmonic of the note analysed.

Everybody who sais that isn´t true or is really no problem and who doesn´t know what speech coding from before (not from) the 80s had to do with pitch matching is basically full of it too much to take as authorative. "But Theo, there are professors ..." Yep. Sure. But there are in certain countries and times also "official" (who get a state salary for that) professors who can be way to full of IT, believe me. Read some good theory books, preferably (if you´re like really good) go over the actual (proof) mathematics of the fourier transform,

    The American Audio Technica AT2020 microphone's specified frequency response graph.

   Compensation of the a AT2020 frequency response with Yamin's 1024-piece equalizer (mirror of the above).

   Patchage and Ingenuity, PureData, Yamin, and meterbridges'  oscilloscope.

   The input of the Lexicon Usb AD/DA converter is fed to rosegarden to record, and to Yamin and Ingenuity for effects.

   A three long signal processing graph between input and output.

Siggraph a year later

Well, is it dead? It seems not, but it sure is exposing to see some of the materials, which I did during a free viewing period of the website for seeing recorded lectures in medium small, fairly good quality streams using quicktime

Honesty sais I used mplayer instead mostly because then I could neatly view in Ful Screen mode, which is quite good, especially when the materials have progressive information in them on HD screen.

   Siggraph 2007 lecture about fibermesh three dimensional shape editing.

An example is shown above of a presentation I viewed, and I downloaded the software from the site too, to make some 3D deformation surfaces with bezier surfaces, which is fun.

This is a Gelato rendering of a blob I made with the java program:

   A 3D claylike figure I designed with the above program, and rendered in high quality Gelato.

Gelato can render NURB surfaces, but clearly the edges and surface accuracies obtained by going through Blender (to read the obj file and create a .pyg model file) are very far from acceptable for high quality image rendering.

So how can I watch the interner movie materials most properly, ha, well, pretty cool:

   A digital cable channel on screen (2.3 meter effectively wide), and the remote server screen in front of the Ikea piece.

The server is meters behind the screen and therefore quiet, the screen is connected through one of two DVI extension cables of 5 meters, which is great, and they can be bought cheap, for instance from conrad, but you may habe to search for hours to  find them. In series works two, except an older graphics card cannot handle that well, so that green spots appear on the screen instead of a certain dark colour. Through the long cable, 10 meter and a DVI to HDMI cable, the projector can be connected to the server where this page is on, preferably at its native 720x1280 resolution. A video digitizer box is also connected with the server over a repeater 5 meter usb cable and then a cable to a hub and then a cable again (8 meters total) , which produces a mpeg video stream which can be viewed live on the beamer in full screen, with full control over mplayer parameters for cropping and stretching and aspect ratio. The laters mplayer I compiled has been improved to work pretty good this way, and keeps up with any material on a 720 screen.

   A cable channel on the beamer, using modest composite connection wire.

How to view my own computer edited video on the beamer? Well preferably use a machine which has:

in it, meaning it has a Nvidia graphics card newer than the 6200 or so, and Purevideo(TM) installed, which is a fairly cheap extension which drives the hardware video renderer in the graphics card to do perfect mpeg-2 video rendering, even in real HD, with absolutely error free results, no lines, blocks, stutters, irregularities, nothing but close to perfection. Of course the material has to be right, and there are general issues for motion interpolation and such where it is about choises, like how to deal with the small LCD slowness, or in the case of the DLP projector, how to interpolate motion to the much faster responsiveness of the little moving mirrors than the frame rate requires.

The projector I think from the looks of it does a small range motion analysis/estimation/correction or maybe 10 or 16 pixels or so, which picks up motion between frames unless the motion is very fast, than jumps are normally visible, depending on how the material is made.

There are advanced issues of course, like wether the image is scaled, and how, and wether there is progresive information in the material, and wether downscaling is required (my 1080HD must be reduced somewhere to 720HD).

Color and intensity are important issues: primarily they should be as close to the original as possible, except when the this is impossible or undesirable because of lack of dynamic range or for artistic purposes. The projector I use is known to be one of the most natural color accurate machines on the market (probably with the exception of big, expensive cinema projectors) and has been tested as such. I use it with great pleasure, and probably will even more than now use it as colour reference.

An how about the light? Well it´s hard to get everything right, daylight, electrical lights in an energy safe way, and the cinema-like properties such as good (mainly absent) reflections from the illuminated screen, a little bit of light to move around and search for remote controls during film, and preferably a dimmer system which can be controlled like cinema lights to go off real slow and real smooth.

   Light dimmer and remote switch, DVI extension connection, audio adaptor.

Above there is the mains prolognation wire spool which is a thick wire grounded cord which is connected to an earthed socket, of which I made the earth connection work myself by hardwiring the ground to a exposed ground wire (unless it would have been a lightning rod) and where the current comes from the same source as the audio system. The dimmer on top is hand controlled but works good, and is mounted on a remote controlled switch, and drives up to 4 lights, a good quality halogen big reflector spot (Philips lamp) which is directed at the sound sweetspot which is of course in the middle a few meters from the screen, and another halogen spot with electronic transformer (which buzzes a bit when dimmed) from the other side, and two small halogen lights in the back with transformers.

I front just visible are a long wire audio connection (for instance for the analog output of the HD cam, which sounds good) and a up to 10 meter long DVI extension cable, which is connected to the black DVI to HDMI cable which is in the back of the projector.


What a name....

As many people by now will know,

   A 3D graphics image created with software written by me.

 photos from theover


Well, ´somebody´ has been looking at houses (since I don´t have any do still at the moment, maybe I should become housing agent or so), even near here:

   Boats in Scheveningen harbour (the Hague) in front of a sailing store on seasailor school open day, processed from HD video.

Though that´s a picture from scheveningen, where some neighbourhoods felt cool, for instance overlooking the dunes, the picture is from the harbour from a piece of HD film I processed, which got to look good. Of course that is a bit of a daring statement that one´s product looks ´good´, because at least that depends on what one views it on, and on what the ideas are that are being communicated.

I wanted a film like effect, which in principle is also about naturalness I think, meaning close to reality, possibly with emphasises and embellishments. Also beauty would depend on the subject and the possiblities of the art form, like the size (number of pixels) of the picture, and in this case the processed fragment is moving pictures, film. Movement and using the 1920x1080 picture elements in every 1/25th of a seconds´ full frame is quite a higher challence than the above frame of a not so moving part of the film piece, which has been shrunk to a smaller size because most people aren´t currently using WUXGA size screens to view this page, inevitably a bit of the detail is lost, and other pixel roundings take place during resizing, and some color or intensity accuracy can be gained by averaging in a good way, and possibly fine noise is less, too. The life which comes from playing the moving footage properly can hardly be represented in any picture.

This is another viewed house, where these pictures come from a quick run through of the place with the HD come, and taking and hobby-processing a few frames from it:

some space!

concrete built!