Pictoric (was: New conversion algorithm)

The Oric video chip is not an easy beast to master, so any trick or method that allows to achieve nice visual results is welcome. Don't hesitate to comment (nicely) other people tricks and pictures :)
sam
Officer Cadet
Posts: 54
Joined: Sun Jul 09, 2017 3:28 pm
Location: Brest (France)
Contact:

Re: New conversion algorithm

Post by sam »

The algorithm should keep oric-compliant images[*] as is. One can check that the total error in the picture is 0 in that case (see highlighted value in screenshot below), meaning that no pixel where harmed during the process.
___
[*] 240x200 pixels, columns 1 to 6 left blank (the algorithm will ignore these pixels anyway), only 8 full-saturated colors max, and same proximity constraints as oric video.
Attachments
Untitled.png

User avatar
Dbug
Site Admin
Posts: 3456
Joined: Fri Jan 06, 2006 10:00 pm
Location: Oslo, Norway
Contact:

Re: New conversion algorithm

Post by Dbug »

sam wrote:
Thu Sep 26, 2019 11:41 am
[*] 240x200 pixels, columns 1 to 6 left blank (the algorithm will ignore these pixels anyway)
Why ignoring the first 6 pixels, does that mean we can't convert a 240x200 black and white picture, it will not convert the first 6 pixels on the left?

sam
Officer Cadet
Posts: 54
Joined: Sun Jul 09, 2017 3:28 pm
Location: Brest (France)
Contact:

Re: New conversion algorithm

Post by sam »

This is because in the code I have put this protection

Code: Select all

local function getLinearPixel(x,y)
    if x<6 then return Color:new() end -- first 6 horiz pixels are reserved
The algorithm doesn't do anything special to those 6 pixels, it is just that I thought that colored pictures always need to have these 6 black pixels in the start of a line to make early changes in the ink more easy. Maybe I can remove this in case of gray-scaled picture since then there is no need for ink-changes. Prepare for a future update then ;)

I you dare the experimentation, you can remove that"if x<6" line and see the result on coloured pictures. Results might be interesting (or disgusting... ymmv)

User avatar
Dbug
Site Admin
Posts: 3456
Joined: Fri Jan 06, 2006 10:00 pm
Location: Oslo, Norway
Contact:

Re: New conversion algorithm

Post by Dbug »

it is just that I thought that colored pictures always need to have these 6 black pixels in the start of a line to make early changes in the ink more easy
It's very common to have Oric pictures (or game screens) start with a PAPER color attribute, sometimes displayed in inverted video to give a different color :)

A good example would be a picture frame: You would have the frame in a particular color, then the canvas in another color, and the portrait on the canvas. You can totally do that on the Oric with putting an inverted PAPER attribute all around (including first 6 pixels), then your normal PAPER color will continue to display itself as background canvas color, which means you can just use your ink changes just after (they will appear as paper color).

EDIT: There's a bunch of pictures here you can test with: http://miniserve.defence-force.org/view ... lope/data/

sam
Officer Cadet
Posts: 54
Joined: Sun Jul 09, 2017 3:28 pm
Location: Brest (France)
Contact:

Re: New conversion algorithm

Post by sam »

I can't get any of the binary file from the svn browser (it shows as ascii, see >>this<<). What's the trick?

I can make that 6 pixel blank margin an option changeable with a flag. But how to detect that the flag is to be set to true or false ? I don't see any well defined decision procedure here: which is best?
1) always black which is more consistent or
2) let the algorithm decide even if this produces weird artefacts of little weight on the total error, but still very visible to the human eye (which prefer regularity.)

[EDIT] Oh! I have an idea. I need to experiment on the images of the SVN (once I can download them successfully ;) )

User avatar
iss
Wing Commander
Posts: 1127
Joined: Sat Apr 03, 2010 5:43 pm
Location: Bulgaria
Contact:

Re: New conversion algorithm

Post by iss »

This link should work for direct download: http://miniserve.defence-force.org/svn/ ... lope/data/

User avatar
ibisum
Wing Commander
Posts: 1355
Joined: Fri Apr 03, 2009 8:56 am
Location: Vienna, Austria
Contact:

Re: New conversion algorithm

Post by ibisum »

I'm so glad you did this project in Lua, its my favourite of all languages..

This afternoon I'm sitting down to use it to build a small art installation which utilises an Atmos I've recovered.

Can I perhaps assist with the repository duties? Only thing you have to do is name the project, and I'll set everything up so that we can have a proper tool that does the Magic. "Oric_tst5.lua" isn't good, maybe you've got a better name for the tool?

If we have a repo, we can share updates/fixes/tweaks, and .. oh man .. having Oric tools in Lua is making me really, really happy. So, you know .. just raising my hand to take on repo duties, if you need/want such a thing.

User avatar
Symoon
Archivist
Posts: 1899
Joined: Sat Jan 14, 2006 12:44 am
Location: Paris, France
Contact:

Re: New conversion algorithm

Post by Symoon »

I got a newbie question. Take for instance Milou in the picture of "Tintin et les Cigares du Pharaon". Milou is all white on the original picture, and IIRC there were dots on him on the final Oric picture.
Could there be a kind of second pass to check the surfaces colour and remove the "dithering that shouldn't be there" on "clean surfaces that have a coulour close to existing Oric coulour" ?
I suspect those dots were here because it wasn't exactly *white* on the original picture, but maybe a bit darker.

sam
Officer Cadet
Posts: 54
Joined: Sun Jul 09, 2017 3:28 pm
Location: Brest (France)
Contact:

Re: New conversion algorithm

Post by sam »

I have just checked >>this<< and >>that<< picture, and milou isn't white. It is #FDFAE9 and #EFEFEF respectively. This probably explains the small dark spots, but I need to check the original I have at home(still at work atm.. ush!! ;) ). [EDIT] in the picture at home milou isn't fully white too.

If you wan't to have a cleaner image, you can modify the saturation of the colors and the white-balance on the image before converting. The tool itself tries to respect the hue&saturation of the colors it was given. It'll just push the luminosity to full range, because it makes the image more clear IMHO (see the normalization parameter in the file).

@ibisum Glad you enjoy lua. This mean you can understand the source. It isn't finished yet. I should add a GUI to alter the various parameters in a easy way on both the cmd-line and in GrafX2.

Do you have a name to suggest? tst_oric5 is just my internal work-in-progress name. (I have one in mind since 5pm (guess why), but couldn't connect it with the tool: Tea-Oric ? :D ) [EDIT or since I live in french britany atm... arm-oric ;) ]

sam
Officer Cadet
Posts: 54
Joined: Sun Jul 09, 2017 3:28 pm
Location: Brest (France)
Contact:

Pictoric (was Re: New conversion algorithm)

Post by sam »

sam wrote:
Thu Sep 26, 2019 11:38 pm
[EDIT] Oh! I have an idea. I need to experiment on the images of the SVN (once I can download them successfully ;) )
Okay.. I tested the idea and it worked well. By default the algorithm uses a heuristic to guess wether or not the first octet of each line should be kept blank or not. Oric's compliant images from the SVN get all their left column unchanged, and even some pictures from the internet do (like this one). This is good result.

So I decided to release v1.0 of the tool as I don't think there will be more research on the algorithm. That version doesn't contains yet support to change parameters from the GUI or from the command line because I wanted to have a K.I.S.S. for a start (keep it simple solution), but it contains a name for the tool/algorithm which I let you discover. A full-featured version for windows users which includes both lua & convert utilities is temporary downloadable (during one week) via >>this link<<.
Attachments
Pictoric_v1_0.zip
Official V1.0 of the conversion algorithm.
(11.67 KiB) Downloaded 123 times

sam
Officer Cadet
Posts: 54
Joined: Sun Jul 09, 2017 3:28 pm
Location: Brest (France)
Contact:

Re: Pictoric (was: New conversion algorithm)

Post by sam »

I have tested few pixel-art pictures from Prowler, and the result is pretty appealing :D
Attachments
forest_dragon.tap.png
forest_dragon.tap.png (4.97 KiB) Viewed 4118 times
floating_on_air.tap.png
floating_on_air.tap.png (5.08 KiB) Viewed 4118 times
a_place_to_be.tap.png
a_place_to_be.tap.png (5.77 KiB) Viewed 4118 times

User avatar
peacer
Flight Lieutenant
Posts: 423
Joined: Wed Jun 09, 2010 9:23 pm
Location: Turkey
Contact:

Re: Pictoric (was: New conversion algorithm)

Post by peacer »

Edward Munch's Scream... Impressive :)

Image

And girl with pearl earring
Image

Dali, of course
Image

User avatar
ibisum
Wing Commander
Posts: 1355
Joined: Fri Apr 03, 2009 8:56 am
Location: Vienna, Austria
Contact:

Re: Pictoric (was: New conversion algorithm)

Post by ibisum »

Really nice! The only thing I don't like about this project is that there isn't a GIT Repo for it yet .. ;)

User avatar
Dbug
Site Admin
Posts: 3456
Joined: Fri Jan 06, 2006 10:00 pm
Location: Oslo, Norway
Contact:

Re: Pictoric (was: New conversion algorithm)

Post by Dbug »

@peacer: If you take the generated pictures and clean the noise pixels (like for example the blue and white dots on the background of the girl with pearl earring or the green pixels at the bottom of the dali, and you reconvert the picture, do you get an even better result?

User avatar
peacer
Flight Lieutenant
Posts: 423
Joined: Wed Jun 09, 2010 9:23 pm
Location: Turkey
Contact:

Re: Pictoric (was: New conversion algorithm)

Post by peacer »

Yes, its possible to retouch the images to remove those noise pixels

But I think, re-conversion looses some "good" pixels too and result is not satisfactory as original ones..

Image

Image

Post Reply