blue screening

[dreambill]

i want to make some homemaid video with the blue screening tecnik, but i dont have a big blue textile, i want to know if they exist a software wich you can capture the movie as normal but when you pass it into this software you can say to this software "keep the peopple and paint the background blue" after i can edit it on premiere. i want to know if this kind of software exist?

sorry for my bad english.
Dreambill

[fingernailX]

http://www.seriousmagic.com/specifications2.cfm

green screen but its the cheapest solution short of a used Trinity Play system

[mats.hogberg]

Dreambill, if that would work, who'd need blue screen at all? You might as well say: "keep the peopple and paint the background (blue) with this image/movie"

/Mats

[solarfox]

dreambill -- I'm sorry to report that what you're asking for, doesn't exist. Computers are not yet good enough at visual pattern recognition to be able to look at a piece of video and say, with certainty, "this pixel belongs to a person, and this one doesn't", so you can't just shoot video as usual and then let the editing software figure out what parts to keep and what parts to throw out. (If that capability existed, they wouldn't spend so much time and money fooling with blue and green screens to start with! )

The system fingernailX points out would do the job, although all you really need from it is the green screen itself... If you really need to do it on the cheap, go pick up a couple of bedsheets (either choose an odd color that none of your "actors" will be wearing, or get some white ones and dye them bright blue or green), then stretch them taut across the back of your soundstage and experiment with lighting it evenly until you get a result you can live with. (Among other things, you must make sure that none of the people or objects in the scene cast shadows against your makeshift screen.)

[dreambill]

Ok thanks for the info Solarfox.
Dreambill.

[rsuave5]

this can be done and the ability to do so has been around for years and computers can tell some pixels from others very easily. i do all the time with premier and its not a trick its made to do it!
cant believe no one is doing it . get the program and buy premiere for dummys at amazon for 15 bux! it tells you how very easily or the web site will tell you for free im low on time but email me later and ill tell you how. its calle dcompositing and i use a white sheet but it leads to errors bright colors work better.

[solarfox]

*sigh...*

I thought my meaning was clear enough in context of the asked question, but apparently some people need it spelled out in words of one syllable or less...

rsuave5 -- whether your sheet is white, green, blue, orange, or puce is irrelevant. The point is that you are supplying the program with a mono-colored, featureless background from which the foreground object can be clearly distinguished because the foreground object will (ideally) not contain any pixels of that color. In those circumstances, yes, Premiere (and Media Studio Pro, and others) can distinguish the person from the background.

What the software cannot do -- and this is what dreambill was asking for, hence my reply was in this context -- is reliably distinguish between and separate a person from a non-monochromatic background. In other words, you can't just start shooting video using the inside of your living room, or the outside of your house, as a backdrop and then later expect Premiere, MSP, etc. to be able to "blue-screen" out the couches, bookshelves, trees, hanging garden hose, etc. and leave only the person you're filming.

Now, if you know of a way to make a consumer-grade PC recognize, reliably and consistently, a person of any arbitrary size, shape, color, and position from any random, uncontrolled background, there are some people in the robotics and machine-vision fields who are very eager to talk to you...

[gll99]

solarfox is correct.

I use videowave 5 and have used it to merge overlay videos of small objects captured against a plain screen but getting a consistent background that can be rendered invisible is difficult to do.

Except for manually cutting around single frames and pasting on a neutral background with limited success, I have never found a software that will allow identifying objects individually unless the video is nested as in flash layers.

I suspect that the pros brightly backlight the green (blue) screen to remove any shadows and create a bright even color.

[The village idiot]

BTW: The proper name for this is called "Chromo Key". At least at most places that deal with television production. Though blue screen will get the point through too.

[solarfox]

gll99 -- That's exactly how its done on a proper TV or movie soundstage. The screen is brightly and uniformly backlit with banks of fluorescent tubes, and made of a non-reflective material (typically a matte-finish plastic with a non-reflective coating similar to that used on camera lenses) so it doesn't pick up reflections of studio lights and foreground objects.

As you can imagine, they're not cheap. However, with a little ingenuity, you can probably cobble your own together if you're mechanically inclined -- I remember seeing one that was made for a student-film project that worked reasonably well. It was a large sheet of plexiglass attached to a wooden frame so it would stand up, with fluorescent tubes mounted horizontally every twelve inches behind the plexiglass sheet; the plexiglass had been scuffed up (with fine sandpaper, I think) on the outward-facing side, both to cut down reflections and to scatter the light coming from the fluorescent tubes, and sheets of gel filter (used for stage lighting) of an appropriate green color had been glued to the inward side between the plexiglass and the lights.

It sounds like a kludge, and it probably was... but apparently, it worked.

village idiot -- It's "chroma-key", actually.

[dreambill]

Thanks a lot Solarfox to understand my bad english and to give me the right answer, i will make some test with blue bedsheets and i will see what happen...

thanks.
Dreambill

[The village idiot]

One more thing... Depending on the camera shot, you might need to put some of the same color on the floor. You might want the sheet to curve toward the floor (like a skateboard ramp) so that you do not have a sharp edge that will be difficult to light.