One who have an eye for Greyness among the Green, vast options open up
who Look forward Green pastures only ... probably loose sight of alternative ideas.
This refers to Chromakey technique adopts a Green screen for the purpose of special-effects in motion picture industry for a long time. But much earlier the preferred colour was Blue as in Blue-screen process.
who Look forward Green pastures only ... probably loose sight of alternative ideas.
This refers to Chromakey technique adopts a Green screen for the purpose of special-effects in motion picture industry for a long time. But much earlier the preferred colour was Blue as in Blue-screen process.
I wish not to dwell upon the choice of colour for painting, but to point out other options available. Here is an example I just stumbled upon, a discussion on black matte by eminent people in the near past yr.2010, but leaves with no solution. How they probably could know an idea that was dormant in my mind since yr.1987 than one find in any print form and now its called as Dgtl-matte
Ref: http://bit.ly/W2mFyg
Introducing Dgtl matte*
Dark-grey trans-lit matte which is self-explanatory and uses a very thinly coated Gray background which is backlit with LED or a suitable light source. I was talking on FS [Flash-selection] matting which is an advanced and complex one to explain than Dgtl matte. So I prefer to commence with Dgtl matting .
Dgtl matte* _patent
Dgtl matte [Dark grey translit matte].
It is quite self-explanatory but is it just all about?
Not really, chromakey follows color-difference which is rather vague idea. But in Dgtl matting I have infused a better strategy called state of change. This is enabled by switching back-light on/off or change intensity in quick succession at every alternate frame or within the capture of single frame [intra frame].
On execution the colour of the background can be varied to a vast range of colours. The bellow colour palette gives a rough idea of variation that can be attained. The highly saturated or brighter colour is intensionally avoided just to demonstrate the efficiency, and also expressing the non-discriminating of colours is the nature of the idea.
The base colour refers to colour of background at prior state, and the changed colour refers to state of change on activating a change with back-light.
Ref: http://bit.ly/W2mFyg
Introducing Dgtl matte*
Dark-grey trans-lit matte which is self-explanatory and uses a very thinly coated Gray background which is backlit with LED or a suitable light source. I was talking on FS [Flash-selection] matting which is an advanced and complex one to explain than Dgtl matte. So I prefer to commence with Dgtl matting .
Dgtl matte* _patent
Dgtl matte [Dark grey translit matte].
It is quite self-explanatory but is it just all about?
Not really, chromakey follows color-difference which is rather vague idea. But in Dgtl matting I have infused a better strategy called state of change. This is enabled by switching back-light on/off or change intensity in quick succession at every alternate frame or within the capture of single frame [intra frame].
On execution the colour of the background can be varied to a vast range of colours. The bellow colour palette gives a rough idea of variation that can be attained. The highly saturated or brighter colour is intensionally avoided just to demonstrate the efficiency, and also expressing the non-discriminating of colours is the nature of the idea.
The base colour refers to colour of background at prior state, and the changed colour refers to state of change on activating a change with back-light.
Dgtl matte takes into consideration to address as many as 17 constrains related to usual chromakey method. Dgtl matting based on a better idea where the execution is very digital-like by making use of difference of state of change i.e, yes/no, on/off.
So inherently it can expected to be 10 times more precise than chromakey an arbitrary scale of comparison. I would assume that it could replace or augment chromakey method. It’s not bad an idea even if it undergoes a natural obsolescence, as it has served almost 65 years in motion picture industry, a long period.
Sounds just lateral thinking or predicting a much broader pic [an Oscar India]
Blue screen & Chroma key :
A similar idea to chromakey in the earlier is known as Blue-screen process or Blue screen matting. To start with Dunning Process used coloured lights and lighting a background screen blue and the foreground subject in yellow invented in 1925 by C. Dodge Dunning. Blue-screen technology as we now refer as chromakey was invented by Larry Butler for the 1940 filming of The Thief of Bagdad. Yellow screen process using sodium vapour lamp in early 50’s by Petro Vlahos.
Petro Vlahos [late]– Green Screen & Special Effects Pioneer Aged 96 Petro Vlahos, a two-time Academy Award winner whose blue- and green-screen technique on movies like "Mary Poppins" and "Ben Hur" made the modern blockbuster possible
So inherently it can expected to be 10 times more precise than chromakey an arbitrary scale of comparison. I would assume that it could replace or augment chromakey method. It’s not bad an idea even if it undergoes a natural obsolescence, as it has served almost 65 years in motion picture industry, a long period.
Sounds just lateral thinking or predicting a much broader pic [an Oscar India]
Blue screen & Chroma key :
A similar idea to chromakey in the earlier is known as Blue-screen process or Blue screen matting. To start with Dunning Process used coloured lights and lighting a background screen blue and the foreground subject in yellow invented in 1925 by C. Dodge Dunning. Blue-screen technology as we now refer as chromakey was invented by Larry Butler for the 1940 filming of The Thief of Bagdad. Yellow screen process using sodium vapour lamp in early 50’s by Petro Vlahos.
Petro Vlahos [late]– Green Screen & Special Effects Pioneer Aged 96 Petro Vlahos, a two-time Academy Award winner whose blue- and green-screen technique on movies like "Mary Poppins" and "Ben Hur" made the modern blockbuster possible
Blue difference matte a complicated process required 12 film elements in late 50’s by Petro Vlahos. Therefore Chroma key is earlier known as Blue screen process dates back to 1950’s. Among these the chromakey process widely used techniques for special effects in motion picture industry. The background colour chosen for chromakey based on such colour difference is Blue or Green in nature.
Dgtl matting overcomes many limitations of Chromakey [C.K], just 4 here among a list 17 at the end of the page.
a. _[C.K]: Calls for planning to exclude colours of dress, props that are closer/similar in colour to the background.
_ Dgtl : almost every colour can be included in the foreground elements. Hence no preplanning required.
b. _[C.K]: Matting based on colour difference has a lesser efficacy than state of change in colour or luminosity.
_ Dgtl : based on on/off, yes/no strategy to threshold level well definable, hence higher efficacy/precision.
c. _[C.K]: Restriction of props that are translucent or transparent which would imbibe the background colour.
_ Dgtl : Back ground colour seen through translucent /transparent object can be controlled.
d. _[C.K]: Restrictions pertains to lighting the foreground elements in terms of angle and type of light source.
_ Dgtl : Adopting lighting of Soft or Hard in nature or various angles has no restriction here.
user un-assist hardware based techniques for matting in Chronological order:
1. Blue screen process - by Larry Butler year 1940
2. Chroma key - by Petro Vlahos, A. R. Smith, J. Blinn. Year late 50’s.
3. Motion control – by John Whitney 1968 ~ John Dykstra, Alvah J. Miller year1977
4. Dgtl matting -by S.Kalaivanan year 1987
5. Flash-selection [Fs] matting - by S.Kalaivanan year 2002
6. Difference matting ~ year 2004* [who when yet to be verified]
7. Defocus video matting - by Neel joshi,M. Mcguire,W.Matusik,H.Pfister, F.Durand, Hughes, Shai Avidan year 2005
8. Coded Aperture – by A. Levin, R.Fergus, F.Durand, W. T.Freeman year 2007.
9. Colour-Filtered Aperture- Depth Matting - by Yosuke Bando, Bing-Yu Chen, Tomoyuki Nishita year 2008
10. Proximatte [Space capture] -- by s.kalaivanan may 2017
Brief:
Dgtl [Dark Grey translit] matting as the name suggests is a matting methodology under image segmentation procedure where region belonging to foreground and that of Background is determined either digitally or optically. Segmentation is determined by state of change of pixel value on every pixel wise location of a frame of image is compared to similar pixel location of another adjacent frame [precaptured or postcaptured] in an image sequence of nominally the same scene in a stream of frames of video capture...........
Chromakey has at least 17 of these following limitations:
1. Many factors could influence defining a colour where the very lighting can be one such influencing factor.
2. Ambiguity prevails in defining a target colour from gamut of colours outside due to transient colour values.
3. Matting based on colour difference has a lesser efficacy than state of change in colour or luminosity.
4. Colour difference matting involves more computation than working on state of change of colour.
5. Calls for planning to exclude colours of dress, props that are closer or similar in colour to the background.
6. The cast colour tinge on artist at foreground when a background having high saturation is brightly lit.
7. Restriction of props that are translucent or transparent which would imbibe the background colour.
8. The background has to be uniformly lit and special equipment needed to measure the uniformity.
9. Extras care needed on lighting to prevent the actor’s shadow being cast on the background.
10. Separate lights are employed to light background brighter to avoid shadow.
11. Brightly lit background encourage lens glare.
12. Restrictions pertains to lighting the foreground elements in terms of angle and type of light source.
13. Due to some of these implication shooting is restricted to indoor under controlled set-up.
14. A larger separation between background and the action at foreground is a must.
15. As background is separated further the size has to be increased proportionally in accordance to camera angle.
16. Restricts choosing a tele in general than adopting a wide-angle lens for a shoot.
17. Above all of background has to be maintained free from seams and streaks.
other references:
http://bit.ly/1mlVRmg
http://bit.ly/1mm2RQd
http://bit.ly/TWkJoZ
http://bit.ly/1qqdIIf