Tag Archives: bad 3d

Is there a secret problem with depth maps?


It sounds like a great idea to utilize a depth map to extract information and control the depth depicted in an image or series of images. It sounds great for converting a 2D image into a 3D image. It sounds like a great tool for plenoptic cameras to interpolate the data into imagery with depth. Alpha channels are great to use for transparency mapping – so a depth map should be equally useful, shouldn’t it?

Take a look at this depth map:

icedepthmapThis is a depth map created from a plenoptic camera shot of a bunch of ice bits. It is a grayscale image with 256 shades of gray to depict the parts of the ice that are closer to the camera and the parts of the ice that are farther away from the camera. This information is used to adjust the depth of those bits that are closer and farther away by stretching or compressing pixels.

Now check out a rocking animation that uses motion parallax to depict the depth (items closer to you appear to move differently than items that are farther away).

ice

Right away you can notice a few errors in the depth map, and for complex images this is typical and can be edited and “corrected”. But there is something else. Take a close look at the parts of the image where the depth map is seemingly correct. Sure, you can see the depth but does it really look like ice? If you are like me, the answer is no. Ice reflects and scatters light in a way that is unique for each perspective. Indeed, there IS binocular rivalry where one eye sees light reflection and distortion that is not present in the other eye’s perspective. This disparity tells us something about the texture and makeup of what we are looking at. Stretching or compressing pixels eliminates this information and only provides depth cues relating to the spatial position of things. For most people, I suspect it is reasonable to assume that this creates a perception conflict in their brains. There is something perceptually wrong with the image above. It does not look like ice because the light coming off of the two perspectives looks the same. A depth map does not provide information regarding binocular rivalry and creates errors as a result. Errors that can’t be fixed. Herein you see the flaw in using a depth map. It throws away all of the binocular rivalry information. In other words, it throws away the information between perspectives that is different.

In my opinion, depth maps take the life out of an image. It removes important texture information which, I believe, is gleaned from how light shifts and changes and appears and disappears as you alter perspective.

This is the secret fundamental flaw with depth maps. Now you can subjectively look at the image above and deem it to be cool and otherwise amazing. That is all good and well, but the truth is that, compared with looking at the real ice, it is fundamentally lacking and does not depict what is seen when you look at the ice in real life.

So, people ask themselves if this is important and some will say yes and some will say no. And there are many examples where you could argue both points of view. I don’t have an argument with that. My position is only to point out that this flaw exists and it should not be ignored.

1 Comment

Filed under 1, 3D, 3D Photography, autostereoscopic, S3D, stereopsis, stereovision

Why Stereoscopic 3D Fails


Why doesn’t the world embrace the illusion of S3D?

It is perhaps the most compelling visual effect that exists for cinema. We have many examples of illusions that become giant successful adaptations. What is it about S3D that keeps holding it back and generates considerable negative press and reviews?

In my opinion there isn’t a singular simple explanation. That is probably the reason for varying degrees of failure in a world of elevator pitches and split second decision making.

Two views, while sufficient to create a compelling illusion, do not fully satisfy the confusing foray S3D makes into the blurring of referential imagery and what I call experiential imagery. We are used to seeing multiple perspectives and on being able to converge our eyes and focus on a specific point in space (unless, like this fellow you are crossing your eyes).

We are used to having multiple confirming points of reference substantiating what we are looking at to be what we think we are looking at.

Some of the many simple explanations are:

–when the reason for looking at something isn’t compelling enough to look at it, then it is going to fail to get attention

–many people do not have normal stereovision

–the ability to suppress perception conflicts is not uniform across the population

A more complex explanation:

–requires education in the field of neuroscience.  The following questions must be addressed:
–How does the brain fuse the input from two eyes into a singular image that depicts space?
–Do we perceive the space between things or do we truly experience it with our vision system?

Many scientists argue that our entire visual system is an illusion that the brain creates, and doesn’t represent reality in the way we think that it does.

The mistake of picking a single simple explanation in terms of success or failure is perhaps the reason S3D comes and goes. The saying: “if you build it they will come” does not always hold true.

So, why choose a career in 3D?

Given the above, why would I choose a career creating imagery that depicts the space between things? Because it is possible to create compelling images to view. It is possible to suppress perception conflicts. Many people DO have normal stereovision. Using science and knowledge of neuroscience it is possible to take advantage of the illusions of the brain.

But the main reason I go forward: art.

As a friend of mine is fond of saying: The Earth without art is simply “Eh”.

3 Comments

Filed under 1

That 3D Stuff Is Crap!


This is one of my favorite quotes because it, very handily, catagorizes what I call the pet rock syndrome of 3D imagery. I tend to agree that 3D imagery that is presented as a gimmick is crap. To say that something is good solely on the basis that it can be perceived with depth is ridiculous.

Why do images need to be created with an illusion of depth?

That question rarely gets answered with a thoughtful response. For many months, I asked myself “What has to be in 3D?”.  And upon reflection, the answer is “not much”.  Portraits don’t have to be in 3D. We can infer depth from a traditional portrait very easily – whether a painting or sketch or photograph. Shadows and lighting depicted in a photograph can infer a sense of depth sufficient that a person looking at it doesn’t feel like the image is lacking. It is interesting how many 3D enthusiasts got that wrong, started a 3D portrait business and were surprised when very few people showed up as customers. Hello! Business rule #1 – identify the problem your customer has and how your product solves that problem. Having a 2D portrait isn’t that much of a problem for most people. 

Do we really need to feel that the image we are looking at needs to occupy the same space we are in? The answer is “not usually”. If we did, would there be a bagillion 2D images on the internet? There are exceptions, and that is what I’ve been working on.

It became obvious to me, when I started looking at tattoos, that traditional photography was seriously lacking. Depicting a tattoo with traditional photography IS a problem. Shadows and lighting do not infer a correct sense of depth for images of tattoos. A referential image with only depth clues is very problematical with regards to depicting tattoos. Tattoo art is unique in that it is experienced in the real world within real world space. To flatten it, is to remove the essence of the art itself. What you are left with is an approximation, a reference that is missing context and the sense of space that it occupies.  It wasn’t until I started creating duplicate 2D versions of 3D prints that I realized just how shocking that difference is. The 2D photograph looks lifeless and abstract as compared to the 3D image. But before I go on, I need to quantify that an AMPED 3D image is not just any old 3D image. Years of research and trial and error have shown me that getting a 3D image right is very complicated. Size matters. Lighting matters. Detail matters. Math and learning about how the brain fuses multiple perspectives into a single image with depth  – matters.  Get those things wrong, and a 3D image of a tattoo isn’t very impressive.

Indeed, it has been several months and I feel that I’ve only reached the baseline of what I need to know to make important AMPED 3D images of tattoos.  Understanding the technical stuff, while difficult, was only part of the requirement.  Understanding the story telling and artistry is even more difficult because it is not transferrable from traditional photography dogma and methods. When you employ immersion and space sharing you are entering completely different territory as compared with traditional referential photography.  Traditional photography has no space and is removed from any sense of realness. That facilitates a much simpler set of rules.

What do I mean exactly?

Well, nobody ever gets confused whether or not a photograph or painting is an actual window or mirror reflecting real life.  They know it is not a real mirror or real person standing in the photograph.  A photograph is a photograph — simple.  Today, it is possible to create an AMPED 3D image that calls “realness” into question. People poke it and look at the back and side, confused at where the space is coming from. An AMPED 3D image can emotionally engage in a completely different way from traditional imagery. This is a different experience that is not well understood. But as understanding grows, we will be able to effectively transition from gimmick “crap” to a completely new art form with amazing possibilities. There are glimmers of quality out there, but quality is the exception and not the rule. In my opinion, Hollywood’s obsession with gimmick 3D will impeede its true potential for some time.  3D TV will be even longer because there are simply too many short cuts and a lack of willingness to thoroughly do the work to understand the issues.

To sum it up, 3D is not going to replace traditional imagery. It can’t, precisely because of what makes it desirable in the first place: a sense of realness. A referential 2D image is easy to interpret because it doesn’t look “real”. Conversely, a 3D image will be easer to experience (which is different than interpretation) the more it matches what we perceive in reality. This isn’t a hard and fast rule as there will always be exceptions. But generally, there is a bias to instantly know what one is looking at so as to easily and quickly make a determination about it. Do we interpret the image or experience it as something real? That is the question to which our brain wants an immediate answer. This is a big problem with 3D imagery because we can’t instantly categorize it in the brain. We have to get past accepting the illusion which takes time.  The key to that is the same for all imagery, and that is to present something that people will want to look at in the first place.  Where the bias is to interpret that imagery in a referential way – traditional 2D imagery is going to always win out. Where the bias is to experience and share the space with the image – 3D imagery will be far more desirable (potentially). But the quality of the illusion is a rate limiting piece of the puzzle.

Trust me, it won’t take long for people to tire of seeing the gimmick of stuff flying out of the screen or something appearing to poke them in the eye. If something is going to be in 3D, then there needs to be a compelling reason for it to be in 3D.  Where a sense of immersion and sharing space with the imagery is integral to the experience – 3D is a giant benefit.  Where thought, inference and referential interpretation are important – people are going to prefer traditional flat imagery for the most part.  I say “for the most part” because novelty does play a roll and in many cases novelty can be fun.

It wouldn’t surprise me to see future films featuring both 3D and traditional 2D within the same film. Also, the use of black and white and different types of color and lighting. The sophistication of the general public is growing. The scope of our experience is changing at a much faster rate and people are much more attuned to all sorts of image treatments, styles and levels of sophistication.

Ok, enough rambling… I’d love to hear other people weight in on this! Is novelty enough to drive 3D into the mainstream? Do people really want to see stuff flying at them out of the screen?

Leave a comment

Filed under 1