A number of products can convert any 2D material into 3D while you watch. Ian Calcutt looks at how it works and how effective it is compared to ‘real’ 3D, as well professionally remastered movie re-releases.
Film studios, hardware manufacturers and some broadcasters continue to push 3D for home viewing but for regular connoisseurs, content is still relatively scarce. However, a feature built into existing 3D Blu-ray players and compatible TVs is 2D to 3D conversion.
This real-time process takes conventional images – sometimes photos too – and processes them to create a sense of added depth if viewers wear the required glasses.
It should not be confused with the movie industry’s costly remastering, which can be applied to feature films not made in 3D but converted and reissued later. A recent example is The Lion King.
“Film studios deploy a much more sophisticated level of conversion as the process does not need to be done live,” says Steve Lucas, product specialist at Panasonic. “Many thousands of man hours can be spent working over each frame, moving each element of an image and changing perspectives to place the convergence point at the most natural position. Powerful software and skilled operators are required to create the best effect. Working with animated features films is easier than with filmed sequences and as technology improves then so will the quality and speed of the process.”
At the deep end
The automated realtime technology in 3D consumer devices uses complex digital calculations. “In order to convert 2D to 3D it stands to reason that processing hardware of higher power is needed,” says Daniel Henry of DirekTek Distribution. “This enables the software to determine which parts of the display are to be in the background or foreground layers, based on how they overlap in 2D.”
Loewe’s picture processing specialist Ralf Müller elaborates: “There are typically several criteria like brightness differences in the picture and certain assumptions, like larger objects are normally more in the foreground than others, and parameters taken from the motion estimation algorithm. Based on that, a depth map is estimated. The final 3D picture is based on the original frame and the corresponding depth map.”
Steve Lucas provides further examples: “A large area of green at the bottom of the image would likely be perceived as grass and set to the front of the image. Conversely a large area of blue at the top of the picture is perceived as sky and sent to the back of the image. Sharp focus equals front, soft focus equals back, and so on. This is simplifying the process of course, as many millions of calculations are taking place each second.”
Change of scene
This approach is often effective but errors can appear in less sophisticated versions of the technology. Ralf Müller adds: “It is important to avoid any scene where the position or relationship of the objects is not akin to reality; for example a house where the door and windows are not at the same level as the rest of the house.”
For Chris Moseley, AV Product Manager at Samsung, if the processing merely looks at luminance, brightness and contrast, it can cause problems. “A good example is an aeroplane and some clouds; the clouds come across as really bright so it put the clouds at the front and the aeroplane at the back, which is the wrong way round. We do perspective, edge detection, lots of other things, which make the end result significantly better.”
Panasonic’s Steve Lucas believes there are advantages in doing processing at source. “Certainly it is better for a disc player that can access the digital data directly from the disc and convert to 3D, than the TV doing it after picture processing. But if the 2D source is broadcast, then the TV should make a better job of conversion. High powered processors such as Panasonic’s P4HD chip used in our BD players and recorders can handle the conversion very well.”
He continues, “Real-time or post-conversion of 2D material will never be as good as shooting the feature in 3D from the start but the effect is reasonable and can be quite enjoyable with the right type of content. The key to the consumer is to provide choice. The option to enjoy all content that can be viewed on a TV in 3D is compelling, not forgetting home-produced family videos and digital still pictures.”
Chris Moseley agrees, “You might have a few hundred DVDs, and if you want to watch in 3D you can have the opportunity to. What we’re not doing is saying, ‘This is going to be the best quality 3D you can get,’ but it’s not going to be far off in some cases. It really does depend on the content.”