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On NTSC Video, Blue Blurring, Chroma Subsampling
NEOGEOman writes "Something I've been fascinated with for a long time is video signals. On my website I've spent over six years collecting video and other hacks for game consoles. I've recently put together the fourth revision of my video signal primer and it's expanded to six pages now, including strange subjects like chroma subsampling, horizontal colour resolution and rather interesting revelation: your eyes suck at blue."
My eyes suck especially badly at blue. a pure-blue image is something my eyes completely refuse to focus on. I can see the image is there, see that it's blurry, but whatever makes my eyes focus just doesn't work on blue. Light a room with pure blue light and I'm almost blind. gah!.
:)
Add some other colours and I'm fine. Curiously, given a red line of text, a green line of text and an off blue line of text, I have to focus differently for all three. (Fully blue is, of course, a complete waste of time
You may want to read a report on misbehaving censorware. Blocking the the article as "pornography" is misbehavior. If your company's business has anything remotely to do with video production or video games, ask your IT department to review gamesx.com (the site on which the article is hosted) and consider whitelisting it.
who's the girl? She's hot ;)
It's well known; as our eyes drift to the blue and red end of the spectrum, we lose our sensitivity, off by many orders of magnitude from say, yellow. This is why you see blue, and more commonly, red, lights as "night" light sources.
The general reasoning: our eyes evolved with a single primary light source: the Sun. Which has quite the yellow tinge to it. Our eyes adapted to this, and as such, gave yellow the highest sensitivity and drifted off in a rough bell curve from there.
It was an interesting article, and certainly put the RGB sensitivity into perspective, but ... it's not entirely new or surprising, either. Nor does the human eye really respond at RGB -- its response curves (beta, gamma, and rho) more closely correspond to blue, green/yellow, and yellow/orange.
That all being said, thanks for letting us meet Traci. ;)
"All your base are belong to this file I send in order to have your advice."
I'm red-green colorblind, and the pictures on the LEFT, with the low-resolution red images, look as good to me as the original or the one with the low-res blue. Does anyone else notice this?
Our eyes suck at seeing blue for an even better reason - there are very few blue things that:
From an evolutionary perspective, that's the most important thing. We're get good at seeing green, because many green things are edible, and some things that want to kill us are good at hiding in green areas. So people who were especially good at seeing movement in green areas, and finding edible green things tended to survive, while those who didn't died out.
"How perfectly Goddamn delightful it all is, to be sure" Charles Crumb
Not necessarily.
SCART connectors are huge chunky things that can handle a number of video formats, including RGB, S-Video and Composite (maybe others too). But that's not the same as saying that a given SCART cable or socket will support all those formats. Many cheaper cables only support Composite (fewer wires means cheaper cost). And on some high-end TVs with multiple SCART inputs, only some of those will support RGB.
So if you're playing your PS2 or whatever through a SCART cable, the TV might be using the SVideo or Composite signal rather than RGB.
The lesson is, be sure to check your TV inputs, and always buy good quality cables!
Yeah, that's me. I did own a gamestore, Traci's on the hood of her car in front of the store in fact. ...
Who's your sister? =)
The author knows he knows nothing, but knows more than the hundreds of info-starved fanboys on forums the world over, and knows enough to put together a primer (And I'm repeating myself here) that is an introduction to a subject, not a comprehensive guide.
;)
Also, as far as I know no one pumps "NTSC DV" through an svideo cable, unlress they're way off spec. Svideo is analogue, not digital. Or are you using a non-spec definition of "DV"?
You have to focus on different colors differently because red, green, and blue light are all different wavelengths and therefore are refracted slightly differently by your eye (shorter wavelengths, i.e. blue, refract more, longer wavelengths - red - refract less). You have to focus closer in on a red light than a blue light for it to be sharp, if you can even do so.
Something I don't understand is that blue light seems to exaggerate my mild astigmatism; I have a Logitech mouse that drives me crazy if I try to focus on the blue taillight. Red lights I can focus on quite clearly and from further away (I am also nearsighted) than any other color lights.
Fun related trivia bit (and forgive me if this is common knowledge):
If you have a decent old 35mm SLR camera with a normal lens (other lenses may have this too) look at the focus ring. There is a marker for where to line up the focus ring in normal conditions, and then there should also be a little red dot a fraction of an inch to the side of it to show where to line up the ring when shooting on infrared film. You have to focus the lens closer for infrared than for visible light, because longer wavelengths refract less.
This is all related the prism rainbow effect, too.