More on 3D Vision

Just to follow on from my last post about 3D anaglyphs I have produced a series of different kinds of anaglyph so you can get an idea of all the different kinds - you can view the images larger by clicking on them.


Above are the left eye and right eye images for all these anaglyphs.

Red+Cyan Anaglyphs

First, the popular red+cyan, of which there appear to be several variations.

Plain old red+cyan.

Then we have a ghost reduced red+cyan, but I am not sure I can tell the difference with my cheap cardboard glasses.

We also have somthing called Dubois Red+Cyan. But I am not yet sure what the difference is here either.

Yellow+Blue (which looks a lot like Ochre+Blue or Amber+Blue)

Here we have a Blue+Yellow. Which incidentally works with the free Sainsbury's glasses for Channel-4's 3D week, and makes me wonder how similar this is to the ColorCode method in my previous post.

In fact what really tipped me off to thinking that yellow+blue was remarkably similar to ColorCode's Ochre+Blue (Amber+Blue) was this 3D Monsters v. Aliens trailer on the ColorCode website:


Is it just me? Or does that look like a yellow+blue anaglyph?

Click to enlarge if you need to, or you can watch the trailer on the ColorCode site here: http://www.colorcode3d.com/gallery/pages/gal_dwa.htm.

Now, it may be true that the specific algorithm that ColorCode patented is better than the one I had access to. But if this also works good enough on an LCD projector then I will be impressed. A poor man's alternative to ColorCode may be yellow+blue anaglyphs - but don't celebrate just yet, I still need to test it on a projector. Watch this space, I will get back to you on that.

Red+Blue

Red+Blue is a combination I remember from my childhood. Its drawbacks, as you can see, are zero colour transmission - the image is effectively monochrome once the glasses are on, and gives a very dark image.


Red+Green

I do remember reading a 3D comic that required red+green 3D glasses when I was a kid. But the yellow background wasn't part of it. In this example, the image has zero colour transmission too, but the image is lighter than red+blue.


The Winners

It is pretty clear that from the examples above the obvious combinations of choice are red+cyan or yellow+blue. Both of these methods give much brighter images, and allow a reasonable amount of colour through.

On the down-side, both red+cyan and the yellow+blue I used do leave traces of ghosting (when you can still see a faint secondary image of the other eye's view). This is called leaking.

Leaking? For example, through a perfect cyan filter no cyan would be visible, but in my tests some cyan faintly leaks through the cyan filter. In part this leaking is what allows for better colour transmission - but you have to put up with a little ghosting. I had a similar issue with my Blue+Ochre Sainsbury's glasses on the yellow+blue image.

It's a toss up, do you want more colour, or less leaking and resulting ghosting?

For me I can put up with a little ghosting for a colour image.

The Losers

I rejected the red+green filter purely because of the yellow background, that just spoils it for me. Unless you are making a movie about 3D custard this particular example is out. However that doesn't mean red+green is no good - it was used to excellent effect in my 3D DVD of Journey to the Centre of the Earth which did not have a yellow background. So I guess my complaint is not about red+green, but this particular way of combining the image for it - stupid algorithm.

While I reject red+blue it does have one advantage over the others. No colour leakage. With the right filters this means a perfect anaglyph, no ghosting in sight. In fact with red+blue its strength is its weakness. The lack of leaking means perfect anaglyphs, but also means low colour transmission resulting in a darker monochrome image.

I guess you can't have it both ways.