Previous 117477 Next
(In reply to)
Messages on Anaglyphs group
Post on Anaglyphs group
Viewed [?00?] time(s)


Subject : Re: [Anaglyphs] To Pierre Meindre - Kwanzan Cherry Tree
From : "forum(-at-)trivision3d.com"
To : anaglyphs(-at-)yahoogroups.com
Date : Mon, 05 May 2014 03:34:51 +0200

117477_Sharock_eagle___Duke_bridge.jpg : (546K)
117477_big_4_hyper_1_04_08_14_A.jpg : (555K)

 


Le 28/04/2014 14:24, pierre.meindre(-at-)free.fr a écrit :

Here is what I get:
On a 55" TV, 55 inches is the diagonal of the screen (about 140 cm) so if the screen is a 16:9 (and if I haven't made a mistake) its width is 122 cm.
On a HDTV horizontal resolution is 1920 pixels so each pixel is 0.63 mm wide.
So 69 pixels are 44 mm on the screen not the 55 mm you are talking about.

------------------------
Hi Pierre,

First a question : is it possible with SPM to change the parameter of automatic mount (like Optimized anaglyph permit) to obtain the right positive parallax pixels of space depending of the monitor, TV, screen projection size ?

69 pixels is for a 55" 3D-TV (LG and PANA tested),  in fact 79 pixels, but like TV "eat" 10 pixels it is reduce to 69 pixels.
On a 42" 3D-TV this become 93 pixels (in fact 103 - 10 pixels "eat" by TV). But if 69 pixels fit also on a 42"(with 3D reduce a bit), the reverse not. For a 65" TV 69 pixels will not fit.
The space of 55 mm is for projection screen, not for standard 3D-TV and I have to make a correcting on my picture bellow to avoid any confusion :( I add in red "only"
It is wrong to think if the positive parallax fit for a monitor it will fit too on any 3D-TV and projection screen.

3D movie in cinema will need a special encoding to permit to the projector to adjust automatically the parallax positive (first for small children eyes space, especially if it is a 3D movie for children).
In add of that many 3D cinema and theme parks have too big screen for the first spectator distance.
An example is the last demand I got from a screen installation wanted a size of 11.26 x 5.20 meter for the FUTUROSCOPE, a 4m for the Confluence museum in Lyon city (France) and a 4m for the museum City of Sciences in Paris. All with too big screen : (


Now regarding your second question :


> on a 3D-TV of 55" verify your distance of "positive parallax" between two homologous dots to infinity, don't must be over 69 pixels.
Can you explain us how you get this number of 69 pixels ???

It is not of my own but from a partner calculation making progress since many years. He is exactly in the same way as a Russian stereographer team editing critic of 3D movies (link edit by Olivier in the SCF monthly revue under the French title "Le relief ça fait mal aux yeux... On commence à savoir pourquoi" / "3D hurt eyes... we starting to know why"). First with others partners making 3D movies, Ophtalmic test, 3D screen mount in cinema, 3D viewers in museum. We notice some children have trouble with some of our pictures (still and motion). We notice also to reduce depth and make more pop-up avoid children trouble, so the trouble was in the positive parallax we an over depth limit giving similar effect than diplopia (see the mixing I permit to do bellow for fun, sorry Duke and Shahrokh... you can't see in the same time the eagle eye and the background bridge...  (or reversal) imagine now this happen much more often to children than to adult because the parallax mount is actually done for adult standard eye space of 65mm, not 55mm for children comfort.
But we had not a real knowledge of stereoscopic geometry. Than this man call me by phone and explained to me his work came first from the book "3D aerial photography" of Louis Phllippe CLERC (1920) and from the book of a old director of the French "National Geographic Institute "IGN" (using also 3D aerial photography to built maps), his name was the General Hurault (also in the past president of the French stereo club... if I'm right). The trouble is all this work fall down with his dead and French stereo club successors forgot it.
 With the help of this new partner since  two years, we discover the stereoscopic geometry with precision and his Euclid equations result and draws was similar to our practice result also similar to the General Hurault and Clerc and the Russian team. When several people (theory and practice) obtain very narrow the same result that mind for my partners and me... could be the true and we have to make attention to study this new partner work. But like hard to understand (I'm not a mathematician) I propose him to make my own draws, he made correcting. Now I offer free the result for stereoscopic
up-grade and will be please everybody verify too. This man want to stay discrete for moment but he is ready to answer with my intermediary to any question from any 3D list.
Bellow is his answer in French to your question. I prefer let you to,make the translation if somebody have interest :
----------------------------------------------------------------------------------------------------------------------
Le calcul du nombre de pixels pour obtenir 50mm entre infinis
sur une TV de 55"
(0,871×55"x25,4mm/1" = 1216mm de largeur horizontale)
(pour une autre taille, seul le 55" est à remplacer par l'autre taille dans le calcul ci-dessus !)
vient du rapport 1920pixels / 1216mm × 50mm = 79pixels,


Le calcul pour obtenir "55mm" entre infinis homologues donnerait bien 1920 / 1216mm × 55mm = 87 pixels, mais hélas, sur l'écran LG de 55" qui a été utilisé, il a été constaté que la réalité mesurée dépassait déjà 65 mm !
Comme si en réalité l'écran montrait moins de 1920 pixels  de large ! ... donc la TV mangeait des marges, donc le taux théorique de 0.63mm/pixels évoqué par Monsieur Pierre Meindre ne correspond donc pas à la réalité de la TV 55" utilisée.
Il a fallu ensuite faire des tests en diminuant progressivement le nombre de pixels entre infinis homologues pour aboutir à obtenir réellement 55mm sur l'écran.

Maintenant a-ton eu raison de faire la supposition que tous les écrans de 55" réagissaient pareils ???
les clubs ou les professionnels ont-il fait une enquête ???
... c'est le moment que chacun indique :
- son nombre de pixels habituels entre infinis homologues lors de la création de son couple
- fasse la mesure réelle en mm sur sa TV, mesure entre ses infinis homologues
- et le fasse savoir

Va-t-on constater que l'on obtient une constante réelle en Pixels/mm attachée à un format de TV ? si c'est le cas, on a eu raison ; si ce n'est pas le cas, ce serait dommage ... car cela voudrait dire que les fabricants d'écran de TV3D ne sont pas conscients que cela est important ! mais les stéréoscopistes devront trouver hélas un moyen de régler cela par un biais quelconque en attendant ... c'est ce qui a été fait sur la TV utilisée, .
------------------------------------------------------


Don't change the picture size...if you change and take some distance fom monitor, will permit to fuse front and background... you see the relation between screen size and first spectators distance !


Transparency permit to change more quickly eyes adjustment.
Try on this one... same trouble !


Of course Duke original picture without front subject do not disturb adults on monitor.


Best regards,

Jm

Le 28/04/2014 14:24, pierre.meindre(-at-)free.fr a écrit :
 

Hi Jean-Marc,

> on a 3D-TV of 55" verify your distance of "positive parallax" between two homologous dots to infinity, don't must be over 69 pixels.
Can you explain us how you get this number of 69 pixels ???

Here is what I get:
On a 55" TV, 55 inches is the diagonal of the screen (about 140 cm) so if the screen is a 16:9 (and if I haven't made a mistake) its width is 122 cm.
On a HDTV horizontal resolution is 1920 pixels so each pixel is 0.63 mm wide.
So 69 pixels are 44 mm on the screen not the 55 mm you are talking about.

Pierre.

----- Mail original -----
De: forum(-at-)trivision3d.com
À: anaglyphs(-at-)yahoogroups.com
Envoyé: Lundi 28 Avril 2014 13:40:10
Objet: Re: [Anaglyphs] Kwanzan Cherry Tree

Nice tree and shoot. If seen on monitor no trouble for me, but if you have some children to see it on a 3D-TV of 55" verify your distance of "positive parallax" between two homologous dots to infinity,
don't must be over 69 pixels. If over, children and adults wit small eyes space having not a brain to make eyes diverge to compensate will see the back ground impossible to fuse (like diplopia)

Jm

28/04/2014 02:12, Brian Wallace a écrit :

I hope this isn't too hyper for some members. It also has a strong TTW effect.

(Sorry I had to leave the trashcans in the shot as cloning them out was too difficult even for the 2D version).

Cha cha, Nikon D600, PS-CS6, SPM, IrfanView.

Cheers,
Brian

My Flickr page: http://www.flickr.com/photos/ur4chun8/
My photos according to "Interestingness"... http://fiveprime.org/hivemind/Tags/Brian,Wallace,3d
My FAA Web page: http://brian-wallace.artistwebsites.com/ or http://pixels.com/profiles/brian-wallace.html
My ArtPal Web page: http://www.artpal.com/Starg82343

Capture Maryland: http://www.capturemaryland.com/users/Starg82343


__._,_.___
Reply via web post Reply to sender Reply to group Start a New Topic Messages in this topic (20)

Check out the automatic photo album with 3 photos from this topic.

Did you check out automatic photo albums in Yahoo Groups?
When you send mail to your Yahoo Group with photos attached, a photo album with attached photos is automatically created. When your group members reply to the email with photo attachments, those photos are added to the 'photomatic' albums automatically!

Attention new and "digest" subscribers: http://abdownload.free.fr/ is the Anaglyphs archive link that includes the photos as well.
.

__,_._,___