Re: Any cure for a washed out keyboard

[linaccess]

On Thu, 31 Jul 2008 17:34:13 +0545
Bryan Berry <[EMAIL PROTECTED]> wrote:

> Thanks Yokoy! I will definitely try that out.
> 
> I figured that it was the impurities in the water that screwed up the
> keyboard not necessarily water itself.
> 
> Does it have to be a large quantity of water or just enough to fully
> submerge the keyboard? Perhaps I need a lot of water in order to get
> enough dissolution

The more the better.  But the best way is to do it in more than one pass, every 
time with fresh distilled water. In that way the keyboard has to be submerged 
fully, not more.

yokoy

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Re: Any cure for a washed out keyboard

[linaccess]

>  A good alternative is ethanol

I mean ethanol >96% , better 99,* %

> 
> Best regards,
> yokoy
> 
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Re: Any cure for a washed out keyboard

[linaccess]

Hi,

the best thing you could do is to put the device (keyboard) into a bathtub with 
distilled water. No joke! after one or two days the electrolyte ingredients 
will be washed out. After that drip of the water and be patient one or two 
days. The device has to be very dry before you should activate the device.
Maybe the display do not like it. 
I am always treating sunken electronic devices that way, including still 
cameras. A good alternative is ethanol (but not denatured alcohol!).  

Best regards,
yokoy

On Thu, 31 Jul 2008 12:44:08 +0545
Bryan Berry <[EMAIL PROTECTED]> wrote:

> The first XO casualty at Nepal's pilot schools a few days ago. A second
> grader washed his XO because it had gotten too dirty.
> 
> Thankfully, the display, cpu and motherboard seem to be working fine.
> The keyboard is non-functional and the mouse is nominally functional.
> 
> Anyone know a fix for a "washed out keyboard" besides complete
> replacement?
> 
> 
> 
> -- 
> Bryan W. Berry
> Systems Engineer
> OLE Nepal, http://www.olenepal.org
> 
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Re: udevsettle takes 33.5 seconds on 2.6.25 master kernels

[linaccess]

On Fri, 2 May 2008 12:10:35 -0400
"C. Scott Ananian" <[EMAIL PROTECTED]> wrote:

> So these failures are not isolated to 2.6.25, and are probably not the
> direct cause of udevsettle taking such a long time.

just to talk at large because I had such problems on another system.
Removing ide-generic and making ata-generic the default fixed the problem. That 
problem apeared  somewhat around the 2.6.22 release, as I remember. After that, 
all /dev/hd switched to /dev/sd. Additional it was a big speed improvement. 
Hope that helps.

yokoy

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Re: Where is Walter?

[linaccess]

On Wed, 23 Apr 2008 14:05:16 +0200
"Bobby Powers" <[EMAIL PROTECTED]> wrote:

> Maybe we could take a break from talking about the sky falling until
> we hear something from Negroponte or someone else at 1CC regarding Windows?


I think everybody would be glad to hear an official statement and nearly 
everybody is wondering why we don't get one.
No statement is a statement.
Anyhow, neither the sugar desktop nor the educational project will die due to 
the great community and the free software. I am not sure if OLPC aka laptop.org 
will survive.

best regard,
yokoy

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Re: PDF reader not really user friendly...

[linaccess]

On Sat, 26 Jan 2008 21:32:30 + (GMT)
[EMAIL PROTECTED] wrote:

> > in general, the OLPC software is and should be different. Maybe not in this 
> > case, if the solution is fine. If the current solution is not fine, the XO 
> > software should be better and due to that different.
> > yokoy
> 
> no, the OLPC software should not be different for the sake of being 
> different. if there is something that is better that may be justification 
> for being different, but difference for it's own sake is not good.

didn't I say that? sorry, I am not a nativ speaker so maybe you did not get my 
intention. I totaly agree in this point.

yokoy

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Re: PDF reader not really user friendly...

[linaccess]

On Sat, 26 Jan 2008 21:11:31 + (GMT)
[EMAIL PROTECTED] wrote:

> the OLPC software should not be any different.

in general, the OLPC software is and should be different. Maybe not in this 
case, if the solution is fine. If the current solution is not fine, the XO 
software should be better and due to that different.
yokoy

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Re: OLPC News 2008-01-26

[linaccess]

nice idea.
the heater could be an add on, just for the extrem cold areas.
yokoy

On Sat, 26 Jan 2008 15:22:57 -0500
"Benjamin M. Schwartz" <[EMAIL PROTECTED]> wrote:

> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA1
> 
> Walter Bender wrote:
> > 5. Batteries: Carla Gomez Monroy reports from Mongolia that the
> > batteries are not lasting as long as expected. The extreme cold was
> > the first suspect. Richard had Carla collect data via olpc-logbat and
> > ran some tests of his own in the freezer (which isn't as cold as
> > Ulaanbaatar). These data, along with a closer examination of the
> > GoldPeak data sheet, make it pretty obvious that batteries don't work
> > so well in the –20 to –40C range. The extreme cold makes the output
> > voltage drop considerably. The result is that at around the 50%
> > capacity mark the voltage is so low that the low-voltage cutoff kicks
> > in and shuts the laptop off. Richard does worry about when the
> > children take their XO laptops outside while suspended; the power
> > dissipation (and thus self-heating) is at its lowest. It may shut off.
> > The question to work out with our battery vendors is that is it OK to
> > de-rate the low-voltage shutoff when it's so cold. Will this do any
> > damage to the battery?
> 
> - From the uninformed crazy ideas department:
> There's a temperature sensor in the battery compartment.  If the EC sees the
> battery temp hit -15C, and at the same time the voltage is, say, 10 mV above 
> the
> low-voltage cutoff, it could _resume_ from suspend, in order to increase load 
> on
> the battery, and therefore increase self-heating.  This would raise the 
> battery
> voltage and extend battery life.
> 
> Mathematically, if effective battery capacity is reduced by cold, and
> temperature is increased by drawing current from the battery, then there may 
> be
> a domain in which drawing current increases the battery's effective capacity.
> This approach would work even better if there were a heating element, or
> something that could be used as such, near the battery.
> 
> - --Ben Schwartz
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> Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
> 
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Re: Violent games on the OLPC Activities page

[linaccess]

On Thu, 17 Jan 2008 10:46:31 -0500
Bryan Berry <[EMAIL PROTECTED]> wrote:

> People can host such games on their own sites but they should not be
> hosted by OLPC.

I quite agree!

yokoy

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Re: can suspend be prevented ?

[linaccess]

hi,

On Sun, 13 Jan 2008 11:55:55 -0800
Joshua Minor <[EMAIL PROTECTED]> wrote:

> Some screensaver APIs have a method to defer sleep/screensaver by a  
> given amount instead of turning it off entirely.  This would let you  
> solve the issue without fear of accidentally disabling it permanently  
> (for example if your activity crashes before turning it back on).
> 

I thought SUGAR takes care about crashed activities? A few lines of extra code 
in SUGAR costs less than an extra screensaver, I guess. If this is not true the 
screensaver API could be a nice way.

yokoy



> -josh
> 
> On Jan 13, 2008, at 1:48 AM, [EMAIL PROTECTED] wrote:
> 
> > Hello,
> >
> > On Sun, 13 Jan 2008 00:51:39 -0500
> > Chris Ball <[EMAIL PROTECTED]> wrote:
> >
> >> Hi,
> >>
> >>> Earlier, had not noticed my G1G1 going into suspend.  Now, with 681
> >>> + d08, it does so when left to sit.  Unfortunately, after suspend
> >>> my wired connection no longer works after the system wakes.  Can I
> >>> prevent suspend from happening?
> >>
> >> Yes, with "touch /etc/ohm/inhibit-suspend".  (And "rm" it when done.)
> >
> > I think, sugar should take care of this if an activity do not want  
> > the suspend feature. When the suspend locking activity has been  
> > finished and there is no other activity that is locking the suspend  
> > "/etc/ohm/inhibit-suspend" could be removed.
> > Maybe an activity could attache a line in /home/olpc/.inhibit- 
> > suspend with it's activity name. When the activity is done, this  
> > line will be removed from itself or sugar. If there is no line left  
> > in this file sugar could remove /etc/ohm/inhibit-suspend.
> >
> >>
> >>> [Seems to me such a situation can occur with a child -- what if he
> >>> is running a science experiment powered from the OLPC USB bus?  He
> >>> would not want his experiment interrupted by the OLPC dropping
> >>> power (as happened to my USB-keyboard when the XO suspended).]
> >>
> >> Yes, we've considered refusing to suspend when certain classes of USB
> >> devices are plugged in.  This hasn't been implemented yet, though.
> >
> > Classes and activities could use the same file as mentioned above?
> >
> >
> > yokoy
> >
> >>
> >> - Chris.
> >> -- 
> >> Chris Ball   <[EMAIL PROTECTED]>
> >> ___
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> >
> >
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> >
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Re: can suspend be prevented ?

[linaccess]

Hello,

On Sun, 13 Jan 2008 00:51:39 -0500
Chris Ball <[EMAIL PROTECTED]> wrote:

> Hi,
> 
>> Earlier, had not noticed my G1G1 going into suspend.  Now, with 681
>> + d08, it does so when left to sit.  Unfortunately, after suspend
>> my wired connection no longer works after the system wakes.  Can I
>> prevent suspend from happening?
> 
> Yes, with "touch /etc/ohm/inhibit-suspend".  (And "rm" it when done.)

I think, sugar should take care of this if an activity do not want the suspend 
feature. When the suspend locking activity has been finished and there is no 
other activity that is locking the suspend "/etc/ohm/inhibit-suspend" could be 
removed.
Maybe an activity could attache a line in /home/olpc/.inhibit-suspend with it's 
activity name. When the activity is done, this line will be removed from itself 
or sugar. If there is no line left in this file sugar could remove 
/etc/ohm/inhibit-suspend.

> 
>> [Seems to me such a situation can occur with a child -- what if he
>> is running a science experiment powered from the OLPC USB bus?  He
>> would not want his experiment interrupted by the OLPC dropping
>> power (as happened to my USB-keyboard when the XO suspended).]
> 
> Yes, we've considered refusing to suspend when certain classes of USB
> devices are plugged in.  This hasn't been implemented yet, though.

Classes and activities could use the same file as mentioned above?


yokoy

> 
> - Chris.
> -- 
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Re: Community Support website for users

[linaccess]

several DNS - incl. openDNS - do not resolve the URL, yet.

yokoy 

On Thu, 27 Dec 2007 10:46:58 -0500
"Samuel Klein" <[EMAIL PROTECTED]> wrote:

> That's funny.  support.laptop.org resolves for me just fine.(it's
> pointing to wiki.laptop.org/go/Support )
> 
> SJ
> 
> On Dec 27, 2007 10:37 AM, Gerard J. Cerchio <[EMAIL PROTECTED]> wrote:
> > Michael Burns wrote:
> > > feel free to use the forum forum, web chat or the email list as a
> > > resource: [EMAIL PROTECTED]
> > > 
> > >
> > > Other support information can be found at http://support.laptop.org/
> > support.laptop.org does not have a server listening as of Dec-27 07:37 PST
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Re: PIL on OLPC

[linaccess]

hi,

I am not in front of my XO. As I could remember I did

CTRL+ALT+F2
root (enter)
yum -y install python-imaging
CTRL+ALT+F3


yokoy


On Fri, 16 Nov 2007 15:12:25 +0100
"Cihan Akkurt" <[EMAIL PROTECTED]> wrote:

> Hi,
> 
> Can someone explain how to install the PIL library on the olpc, for Image
> module use, please.
> I need this module to rezise and save images for my software. thank you
> 
> -- 
> **
> Cihan Akkurt
> 
> E-mail : [EMAIL PROTECTED]
> 
> Msn : [EMAIL PROTECTED]
> 
> Skype : akkuciha
> 
> **
> 


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Re: Bundling Commercial XO With Ecomstation

[linaccess]

hello 'big one'

you don't like the keyboard, the display, the network hardware and in addition 
you want to get rid of sugar/activities by replacing it with DOS/Windows clones 
and semi free software. IMHO neither the XO nor the Sugar Project and their 
philosophy are the right stuff fitting your needs. I think we could not help 
you but maybe this is the hardware you are searching for:
 http://www.koolu.com/content/blogsection/6/11/

Regards,
yokoy



On Thu, 27 Sep 2007 07:23:15 -0700
"big one" <[EMAIL PROTECTED]> wrote:

> In 1990s IBM released a Windows NT competitor called OS/2 that can run 
> MS-DOS, Windows 3.1 and Windows NT applications (using special method). Now 
> Serenity Systems had bought OS/2 from IBM and market it as Ecomstation. 
> 
> http://www.ecomstation.com
> 
> Collection of freeware/shareware OS/2 applications:
> http://hobbes.nmsu.edu/
> 
> If Ecomstation can support XO laptops BIOS and still run MS-DOS, OS/2 and 
> Windows 3.1/Windows NT program, IMO this new version of Ecomstation can be 
> bundled with Commercial version of XO laptops sold to developing countries 
> (US, Europe, Japan, Middle East).
> 
> Perhaps the developing countries version of XO come with bigger keyboards, 
> LCD screens, but use the same motherboards and chipsets as the developed 
> country version.
> 
> Is the above idea possible?
> Thank you.
> 
> _
> = You want FREE web-based email ? 
> = You want your own @qon.lao.net address??
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Re: radio off guarantee?

[linaccess]

moin,

On Tue, 18 Sep 2007 14:42:51 +1000
James Cameron <[EMAIL PROTECTED]> wrote:

> > Do we need a solid way to turn off the RF before it's OK to use an XO
> > on an airplane?
> 
> Our target market usually won't have this problem.

Yes, but the developers need a solid way to switch of the RF. The Test XO 
target market are developers and sometimes they travel by air.

Javier wrote:
# killall NetworkManager
# iwpriv eth0 radiooff

How could we ensure not bringing up the RF at boot time? Which file takes care 
of this at fedora systems?

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Re: headtracker / mag lens / macro lens ([EMAIL PROTECTED])

[linaccess]

Hello Luke,

thanks for that appraisal.

yokoy

On Thu, 6 Sep 2007 14:53:15 -0400
"Luke Hutchison" <[EMAIL PROTECTED]> wrote:

> OpenCV looks much more heavyweight than what you need, but may be useful in
> prototyping.
> 
> Phase correlation looks for the translational offset of an entire image
> between two frames.  It is also probably much more heaviweight than what you
> need.  In the end the result you get will be pretty similar to that obtained
> by the centroid method.  You will only get higher than single-pixel
> precision with phase correlation if you do subpixel extremum detection
> anyway, and you can do that directly in image space, saving a lot of
> computation.

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Re: headtracker / mag lens / macro lens ([EMAIL PROTECTED])

[linaccess]

Hi,

On Thu, 06 Sep 2007 14:55:31 -0400
"Benjamin M. Schwartz" <[EMAIL PROTECTED]> wrote:

> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA1
> 
> Have you ever used a IBM/Lenovo Thinkpad laptop with the red joystick-mouse in
> the middle of the keyboard?  These use the position of the joystick to control
> the velocity of the cursor.  I am using one right now, and I find it quite
> effective.  The joystick only is able to record a few positions, but because 
> it
> is used to set velocity, the effect is very high precision.
> 
> This might allow very small motions to be used, improving comfort.
> 

yes, I am sitting at an ibm x20 right now and I like that build in stick from 
IBM much more than touchpads. On the other hand I used such a stick on a 
toshiba, too. It was horrible...

> - --Ben
> 
> 
> P.S. I have now realized that phase correlation is probably unnecessary for 
> you,
> because your image already contains a single bright spot.  Phase correlation
> would be appropriate if you wish to attempt this without the reflector, based 
> on
> the face itself.

OK. I still want to realize as much as possible hardware based (well, depends 
on price). The XO is a slow machine so some time ago I concluded to wipe out 
unneeded information using IR LEDs and IR Filter. With that the activities 
should stay usable without slowed down a lot. The board, IR LEDS, reflectiv 
foil, IR Filter and the resistor costs less than 1,5 Euro. Buying them as an 
end customer. Put those parts onto the XO board by default would cost only a 
few cents.

Maybe the next generation of XO have intergrated them? A small slot in front of 
the webcam lense could pick up various filters and lenses. Also suitable for 
microscope projects.

yokoy
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Re: headtracker / mag lens / macro lens ([EMAIL PROTECTED])

[linaccess]

Hello Yuan Chao,

a special pattern could be a way do stabelize the tracking and make it immun to 
not relevant movements. On the other hand it slows down the XO enormously, 
IMHO. Tacking the whole face is not at issue, I think. We have to do tests some 
day...

regards,

yokoy 

On Thu, 6 Sep 2007 17:42:32 +0800
"Yuan Chao" <[EMAIL PROTECTED]> wrote:

> On 9/5/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> 
> Hi Yokoy,
> 
> > tracking a little shiny point at the head and transform it into 
> > mousepointer movements. Here is the description:
> > http://www.olpcaustria.org/mediawiki/index.php/Headtracker
> I don't how much computation power needed to track a pattern. I
> remember that for some webcam drivers provide different image sizes.
> If the effort is small enough, maybe you can consider tracking a
> pattern instead of light points, or even more, the face position. A
> small sticker with the special pattern on head or glasses would be
> enough. Also too precise tracking would be painful once you need to
> hold the position still when not moving. One thought would be to act
> like a "trackpoint" on thinkpad computer: when moving within some
> threshold, the position holds; when move further, the positioning
> moves continuously till move back within the threshold. The further
> above the threshold, the faster the positioning moves.
> 
> 
> -- 
> Best regards,
> Yuan Chao


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Re: headtracker / mag lens / macro lens ([EMAIL PROTECTED])

[linaccess]

Hi Luke,

thanks for the suggestion, it sounds good in my ears.

If we use absolute or relative values depends on the user and his potentiality. 
In the first place the headtracker is an accessibility issue. Second, we all 
have benefit from accessibility software. I really would like to get rid of the 
touchpad. Using a touchpad is a bit like ZEN :-) Having both hands on the 
keyboard all the time accelerates the workflow enormous.
Maybe we could put a slider into the activity where the user select absolute, 
relativ or somewhat between that.
The user should also define a activ area. Outside this activ area there could 
be car traffic or smokers with lighters, doesn't matter. There is no need to 
process this area and there are less problems with jumping mouse pointers.

Is it possible to give an active area to the camera? That would speed up the 
processing and maybe the framerate.

regards,
yokoy



On Wed, 5 Sep 2007 19:52:38 -0400
"Luke Hutchison" <[EMAIL PROTECTED]> wrote:

> I see, so the camera sensor area covered by moving your head in-place to
> point to the four corners of the display is approximately 90x30.
> 
> I think you are saying that the image of the reflective dot is a blob of
> neighboring pixels of size 5x3 to 20x12 somewhere on the display.  If that
> is the case, then taking the centroid is probably the best approach.
> However I may make a suggestion to improve accuracy:
> 
> -- Threshold image at some minimum brightness
> -- Find largest blob of connected pixels above threshold, and put them into
> a set B
> -- Put all pixels just inside or just outside the edge of the blob into a
> set E
> -- Find all internal pixels I = B \ E  (all pixels in B that are not in E)
> -- Linearly scale the (floating point) intensity of all pixels in E so the
> brightest is 1.0 and the darkest is 0.0.  (Beware of division by zero if all
> edge pixels are the same intensity.)
> -- Set the intensity of all pixels in I to 1.0
> -- Find the weighted centroid of (I Union E), by multiplying the pixel
> intensity by the x and y coords, and summing for x and y, then dividing x
> and y sums by the total of all pixel intensities.
> 
> What this effectively does is give all internal pixels equal weight in
> calculating centroid position, and then it uses the normalized shade of edge
> pixels to fractionally adjust the centroid position.  This effectively
> reverses the antialiasing that occurs at the edge of the image of the dot on
> the CCD.  You really should be able to get some good resolution using some
> sort of approach like this.
> 
> By the way, as someone pointed out in another post, trying to hold your head
> in position and just tilt it slightly to reach the corners of the laptop is
> likely to give you a knot in your neck!  You should probably allow the user
> to move their head further (because their effective range is extended by
> their eyes).  You might also want to consider doing some eye tracking, so
> that the user can blink twice to turn the head tracking on or off, for
> example, and maybe wink to trigger a L/R mouse button action.
> 
> Also you should look at relative positioning and not just absolute
> positioning: e.g. the cursor doesn't move unless you move your head quickly,
> and the movement is only part of the width of the screen each time -- that
> way you can move the cursor in several steps, by moving quickly forward in
> one direction, then slowly back, much the same way as you do with a touch
> pad, except that touching/raising your finger is emulated by the speed
> threshold.
> 
> Luke
> 
> 
> 
> 
> On 9/5/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> >
> > Hello Luke,
> >
> > I will consider the paraboloid thing, thanks for the code.
> >
> > I am not tracking only one point. I am tracking a bundle of points - say
> > 5x3 to 20x12 - and it changes all the time with different ratio. Out of
> > those pixels (and maybe some time) I have to build an AVG Pixel with a
> > defined XY value. AVG pixel != brightest pixel. For that AVG pixel I could
> > use subpixel, too. I have to use subpixel because I have to map the low
> > resolution to 1200x900 pixel if I try to use absolute coordinates.
> > Where do I get the size 90x30 from? It is not an pixel exact value but a
> > approximation. It differs.
> > I tried not to move my eyes but my head and looking to the four corners
> > and the center of the XO display. The display is very small so I moved my
> > head really not to much. One infrared filtered result merged from 5
> > snapshots (four eges and center) is here:
> >
> > http://www.olpcaustria.org/mediawiki/upload/7/79/Headtracker_area_small.jpg
> > It is downsized from 640x480 to 320x240px but the relation is the same.
> >
> > Maybe I have got a knot in my brain. I really like to get the headtracker
> > working in a good way without an additional lens.
> > Again the link to the project site:
> > http://www.olpcaustria.org/mediawiki/index.php/Headtracker
> >
> > greeting,
> > yok

Re: headtracker / mag lens / macro lens ([EMAIL PROTECTED])

[linaccess]

hi,

has anybody experince (and libs) with phase correlation?
I have no idea how to implement it.

Another promising lib is 
http://en.wikipedia.org/wiki/OpenCV

greeting,
yokoy



On Wed, 05 Sep 2007 19:40:29 -0400
"Benjamin M. Schwartz" <[EMAIL PROTECTED]> wrote:

> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA1
> 
> I am not at all clear on what you are doing, or why.  However, you may want to
> check out
> 
> http://en.wikipedia.org/wiki/Phase_correlation
> 
> this is the most accurate possible method for recovering the position of a
> moving object.  If you have a fast FFT available it may be quite efficient.
> 

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Re: headtracker / mag lens / macro lens ([EMAIL PROTECTED])

[linaccess]

On Wed, 05 Sep 2007 12:40:38 -1000
Mitch Bradley <[EMAIL PROTECTED]> wrote:

> [EMAIL PROTECTED] wrote:
> > I tried not to move my eyes but my head and looking to the four corners and 
> > the center of the XO display. The display is very small so I moved my head 
> > really not to much ...
> >
> > Maybe I have got a knot in my brain. 
> >   
> 
> I'm pretty sure that if I had to keep my head still to avoid moving the 
> mouse, I would have a knot in the back of my neck after a short time.  
> Whether the knot would then travel to my brain, I don't know.  :-)
> 
>

lol
after working with the touchpad it feels like having knots in my wrist and 
fingers. It could not be worse :-) 

BTW, the activities and sugar need (more) shortcuts to control the XO without 
the touchpad or mouse. 

yokoy

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Re: headtracker / mag lens / macro lens ([EMAIL PROTECTED])

[linaccess]

Hello Luke,

I will consider the paraboloid thing, thanks for the code.

I am not tracking only one point. I am tracking a bundle of points - say 5x3 to 
20x12 - and it changes all the time with different ratio. Out of those pixels 
(and maybe some time) I have to build an AVG Pixel with a defined XY value. AVG 
pixel != brightest pixel. For that AVG pixel I could use subpixel, too. I have 
to use subpixel because I have to map the low resolution to 1200x900 pixel if I 
try to use absolute coordinates.
Where do I get the size 90x30 from? It is not an pixel exact value but a 
approximation. It differs.
I tried not to move my eyes but my head and looking to the four corners and the 
center of the XO display. The display is very small so I moved my head really 
not to much. One infrared filtered result merged from 5 snapshots (four eges 
and center) is here:
http://www.olpcaustria.org/mediawiki/upload/7/79/Headtracker_area_small.jpg
It is downsized from 640x480 to 320x240px but the relation is the same.

Maybe I have got a knot in my brain. I really like to get the headtracker 
working in a good way without an additional lens.
Again the link to the project site:
http://www.olpcaustria.org/mediawiki/index.php/Headtracker

greeting,
yokoy




On Wed, 5 Sep 2007 12:57:54 -0400
"Luke Hutchison" <[EMAIL PROTECTED]> wrote:

> PS there's a "cheap" way you can accomplish subpixel accuracy, as follows.
> You basically take a bunch of 1D samples through the brightest pixel,
> looking at 2 neighbors in each direction, and then take a weighted sum of
> the results.  This calls the code I pasted in the last email.  It's not
> going to be as good as paraboloid regression, but it should allow you to
> test feasibility.
> 
> 
> // Do a 2D parabolic fit to give sub-pixel accuracy for translational
> // registration, by performing four 1D parabolic fits through the closest
> // integer correlation offset: horizontally, vertically, and on the leading
> // and trailing diagonals.  Take the weighted centroid of all four to get
> // the true correlation offset.
> 
> // off_x and off_y are the one-pixel-accurate correlation offsets recovered
> // by correlation.
> 
> // x1d and y1d are x and y values for the 1D quadratic fit function
> double y1d[9] = { // Get magnitudes at (off_x,off_y) and 8 neighbors
>   dft_mag(dft, off_x - 1, off_y - 1),
>   dft_mag(dft, off_x, off_y - 1),
>   dft_mag(dft, off_x + 1, off_y - 1),
>   dft_mag(dft, off_x - 1, off_y),
>   dft_mag(dft, off_x, off_y),
>   dft_mag(dft, off_x + 1, off_y),
>   dft_mag(dft, off_x - 1, off_y + 1),
>   dft_mag(dft, off_x, off_y + 1),
>   dft_mag(dft, off_x + 1, off_y + 1)
> }
> 
> // Sum contributions to centroid of each quadratic fit
> double x1d_tot = 0.0, y1d_tot = 0.0, x1d;
> 
> // Parabolic fit in horiz direction through correlation maximum
> x1d = parabolic_fit(-1, y1d[3], 0, y1d[4], 1, y1d[5]);
> x1d_tot += x1d;
> 
> // Parabolic fit in horiz direction through correlation maximum
> x1d = parabolic_fit(-1, y1d[1], 0, y1d[4], 1, y1d[7]);
> y1d_tot += x1d;   // [x1d is x in parabola space, but y in correlation
> space]
> 
> // Weight contributions of diagonal by the inverse of their distance
> #define RT2_OV_2  0.7071067811865475244   // sqrt(2)/2  (= 1/sqrt(2))
> 
> // Parabolic fit in leading diagonal direction through correlation maximum
> x1d = parabolic_fit(-1, y1d[0], 0, y1d[4], 1, y1d[8]);
> x1d_tot += x1d * RT2_OV_2;
> y1d_tot += x1d * RT2_OV_2;
> 
> // Parabolic fit in leading diagonal direction through correlation maximum
> x1d = parabolic_fit(-1, y1d[2], 0, y1d[4], 1, y1d[6]);
> x1d_tot -= x1d * RT2_OV_2;
> y1d_tot += x1d * RT2_OV_2;
> 
> // Take centroid of all parabolic fits, weighting diagonals by RT2_OV_2;
> // make relative to correlation coords by adding off_x, off_y
> double subpix_off_x = off_x + x1d_tot / (2.0 + 2.0 * RT2_OV_2);
> double subpix_off_y = off_y + y1d_tot / (2.0 + 2.0 * RT2_OV_2);
> 
> 
> 
> On 9/5/07, Luke Hutchison <[EMAIL PROTECTED]> wrote:
> >
> > Where do you get the size 90x30 from though?  Are you saying you can't get
> > at the full-sized frame through the API currently?
> >
> > You really should consider fitting a paraboloid over the dot to get
> > sub-pixel resolution.  Note that if the dot is bigger (more than a few
> > pixels), you probably want to just use the weighted centroid, but if it's
> > small, a paraboloid is the right approach.  You really will get at least a
> > 10x increase in accuracy in both x and y, bringing your effective resolution
> > to something like 900x300 for the example you gave.  You may not even need a
> > lens.  I have used this before with success for an image processing project.
> >
> >
> > Here's the code for the 1D version:
> >
> > // Fit a parabola to three points, and return the x coord of the turning
> > // point (point 2 is the central point, points 1 and 3 are its neighbors)
> > double parabolic_fit(double x1, double y1,
> >  double x2, doub

Re: [sugar] Pippy and Calculate

[linaccess]

hi,

On Wed, 05 Sep 2007 13:00:50 +0200
Reinier Heeres <[EMAIL PROTECTED]> wrote:

...

> I just think the two activities are suited for different 
> things.

...

yes, I agree. A calculator is not to learn python.
Some time ago the calculator activity looks like real pocket calculator and I 
think that was a good way. I was a bit disappointed about some changes the 
calculator overcomes.
I like the idea to put some interface stuff from the TI89 and the option to 
program inside the calculator activity. 

Pippy is more an activity to learn python, did I understand right? So you could 
also do math in it but it is not in the first place a calculator.
I like Pippy (oh, what a sentence. For german ears it sounds like 'I like 
wee-wee' :-) but it is not the right activity to replace a calculator IMHO.

regards,

yokoy
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Re: headtracker / mag lens / macro lens ([EMAIL PROTECTED])

[linaccess]

Hello Luke,

On Tue, 4 Sep 2007 16:11:34 -0700
"Luke Hutchison" <[EMAIL PROTECTED]> wrote:

> Is the processing time for 640x480 the reason you're only using 90x30?
>

No, I am not at the point thinking about optimization the processing time.
You don't want to dance in front of the camera to control the mouse pointer. 
You just want to move your head a few degrees as if you would look to the edges 
of the display without moving your eyes. Then the area recognized from the 
camera is very small. It is like moving the mouse only one or two millimeters 
to move the mousepointer over the whole desktop. To get more 'delta pixel' I 
need a mag lens, I think.

regards,

yokoy


 
> You can actually dramatically increase the precision to which you can read
> back the bright point's location by fitting a paraboloid to the intensity
> values in the neighborhood of the brightest pixel, then reading off the
> location of the extremum of the paraboloid.  You will get at least one order
> of magnitude more accuracy that way than looking at the integer coords of
> the brightest pixel (perhaps as much as two orders of magnitude).
> 
> Luke
> 
> 
> On 9/4/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
> >
> > Hello Mary Lou,
> >
> > On Tue, 04 Sep 2007 12:13:34 -0400
> > Mary Lou Jepsen <[EMAIL PROTECTED]> wrote:
> >
> > > lenses are cheap.  it depends on what exactly you are doing with the
> > > software.
> >
> > tracking a little shiny point at the head and transform it into
> > mousepointer movements. Here is the description:
> > http://www.olpcaustria.org/mediawiki/index.php/Headtracker
> >
> > With the XO camera we typicaly use only 90x30 pixel from the 640x480
> > pixel. So I want to magnify the operative area with a lens.
> > Here is a picture of the area:
> >
> > http://www.olpcaustria.org/mediawiki/index.php/Headtracker#magnification_lens
> >
> >
> >
> > > American Science and Surplus is a good way to experiment:
> > > http://sciplus.com/category.cfm?subsection=21
> > >
> >
> > thank you for that link. A plastic lens is what I am searching for.
> >
> >
> > > then to china for mass production at very low price point.
> > >
> > >
> > > - Mary Lou
> > >
> > >
> >
> > regards,
> >
> > yokoy
> > --
> >
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> >
> 


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Re: headtracker / mag lens / macro lens ([EMAIL PROTECTED])

[linaccess]

Hello Mary Lou,

On Tue, 04 Sep 2007 12:13:34 -0400
Mary Lou Jepsen <[EMAIL PROTECTED]> wrote:

> lenses are cheap.  it depends on what exactly you are doing with the
> software.

tracking a little shiny point at the head and transform it into mousepointer 
movements. Here is the description:
http://www.olpcaustria.org/mediawiki/index.php/Headtracker

With the XO camera we typicaly use only 90x30 pixel from the 640x480 pixel. So 
I want to magnify the operative area with a lens.
Here is a picture of the area:
http://www.olpcaustria.org/mediawiki/index.php/Headtracker#magnification_lens


 
> American Science and Surplus is a good way to experiment:
> http://sciplus.com/category.cfm?subsection=21
>

thank you for that link. A plastic lens is what I am searching for.

 
> then to china for mass production at very low price point.
> 
> 
> - Mary Lou
> 
> 

regards,

yokoy
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headtracker / mag lens / macro lens

[linaccess]

Hello,

am searching for a cheap mag lens to improve the resolution of the headtracker.
http://www.olpcaustria.org/mediawiki/index.php/Headtracker

What I have found is a very cheap macro lens. I took it from a one-way-camera 
and put it directly in front of the web cam lens. The difference is obvious. 
But I did not find a magnification lens, yet.

http://www.olpcaustria.org/mediawiki/index.php/Headtracker#magnification_lens

By the way, how could I make high resolution / less compressed pictures and 
videos with the XO?  


regards,

yokoy

ps: sorry for cross posting
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[olpc-devel] re:

[linaccess]

Hi,

it would be nice if we have always an additionally subject like [olpc-devel] 
inserted automaticaly from devel-bounces. I did it this time manually. 
Otherwise  looks like spam...

@Mike: please define always a subject

thanks,

yokoy



On Thu, 23 Aug 2007 12:14:45 +1200
Mike Usmar <[EMAIL PROTECTED]> wrote:

> OK, hopefully this is an easy question I want to upgrade to build 542, and
> have the downloaded and un zipped to a UDB drive in boot the olpc-auto.zip,
> and the latest OS image and  .crc file, so in the boot directory I have 6
> files q2c24.rom; os542.img; os542.crc; usbupgos.img, usbupgrd.img, and
> olpc.fth
> 
> I power up the Laptop and get this message
> 
> Noot devices /usb/disk:\boot\olpc.fth arguments:
> <[EMAIL PROTECTED]>:17:Tyuy_mask?
> 
> Somebody tell me what I am doing wrong
> 
> Mike U
> 
> 
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Re: X trapezoids rendering performance

[linaccess]

hello bernardo,

Stefano cc_ed you, you saw that mail only once. Ask your provider or your admin 
:-)

yokoy


On Wed, 22 Aug 2007 16:58:25 -0400
Bernardo Innocenti <[EMAIL PROTECTED]> wrote:

> Stefano Fedrigo wrote:
> 
> > [...]
> 
> I can't see your mail in [EMAIL PROTECTED]  Are you subscribed to it?  It's
> a subscription only list.
> 
> -- 
>// Bernardo Innocenti
>  \X/  http://www.codewiz.org/
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Re: DejaVu fonts (Was: Ethiopean)

[linaccess]

Hello Bernardo, All,

I wonder about shipping DejaVuLGC, too. I ask the same questions a few weeks 
ago on #olpc / #sugar but didn't get an answer. Ok, it is irc and not a 
mailinglist. Thanks for posting it here.
IMHO we should try to switch from DejaVuLGC to DejaVu. Frontiers are not 
perforce language borders. So it would be fine to have as much fonts on the XO 
as posible. There is always the chance to switch back. Besides we have less 
packages and maybe more space for free.

Regards,
yokoy


On Tue, 21 Aug 2007 20:01:17 -0400
Bernardo Innocenti <[EMAIL PROTECTED]> wrote:

> (I'm moving to devel@ so we don't need to Cc too many people)
> 
> Bernardo Innocenti wrote:
> > Sergey Udaltsov wrote:
> > > I cannot tell you which font was used by my Ubuntu - I just see those
> > > glyphs rendered more of less correctly (see attached). If you're
> > > interested, I can provide you with the list of fonts I have installed.
> >
> > I see them just fine in Firefox on my F7 development machine, but not on
> > the laptop.  Weird...
> 
> It turns out that the DejaVu font has the Ethiopian glyphs, but
> there's also a simplified font called DejaVuLGC which is what
> we're shipping on the OLPC.
> 
> I just talked with Walter and J5 and we agreed that it makes no sense
> to ship a huge font with all glyphs when we're already going to have
> a custom images for each country where we can easily add language
> specific fonts.
> 
> But now I looked at DejaVu to see how bigger it is and it seems to
> me that it's not worth it after all:
> 
> -rw-r--r-- 1 root root 448K 2007-08-11 07:42 DejaVuLGCSans.ttf
> -rw-r--r-- 1 root root 557K 2007-08-11 07:42 DejaVuSans.ttf
> 
> The RPMs for the complete DejaVu font are even *smaller*:
> 
> -rw-r--r-- 1 root root 2.0M 2007-08-11 07:43 
> dejavu-fonts-2.19-1.fc8.noarch.rpm
> -rw-r--r-- 1 root root 3.3M 2007-08-11 07:42 
> dejavu-lgc-fonts-2.19-1.noarch.rpm
> 
> (but that's because DejaVuLGC also comes with Condensed variants).
> 
> So, is there another reason why we couldn't just switch to it?
> Currently, we're shipping arabic and thai fonts in all builds.
> If the DejaVu support for these languages is good enough, we
> could save even more space.
> 
> -- 
>// Bernardo Innocenti
>  \X/  http://www.codewiz.org/
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