Illumination Object Wave The Object Wave has amplitude, frequency, and phase. I take regular ‘samples’ in each eye. Object Wave How does our natural viewing system work?
What happens in 3D in the mind? The two pictures from the retinas of the eyes are corrected for distortion, laid one on top of the other, ‘fused’ by the mind (‘stereopsis’), and projected forward as if seen by a single eye in the forehead (the cyclopean image).
The problem for 3D TV. Sensors record only the amplitude of the light, not the wavelength or phase. We get over the problem of wavelengths in Television today by recording ‘three pictures’ each with ‘primary colours’. We cannot yet record phase in a practical sensor system (though a hologram does this). We will eventually solve this problem. But today we start with a limited system of 3DTV (“S3D”) and accept a particular limitation in focussing.
3D Levels and Profiles Conventional Service Compatible (CSC) Level 3 2D HD +something Frame Compatible Compatible (FCC) Level 3 Frame Compatible + something Conventional HD Frame Compatible (CFC) Level 2 Frame Compatible Conventional HD Display Compatible (CDC) Level 1 Colour anaglyph Plano-stereoscopic 1 st Gen Multi-view 2 nd Gen. Integral TV 3 rd Gen. Object Wave 4 th Gen. No new equipment No new set top box, but 3D display New set top box/ird/3D display
Recap: ITU Generations (Profiles) of 3D-TV First Generation 3D-TV. Record two samples of the Object Wave (Amplitude, Frequency via primaries, No phase). Characteristic: depth, but nothing changes as it should when you move your head. Focusing doesn’t work. Second Generation 3D-TV. Record a large number of pairs of signals (multi-view). A ‘quantized’ horizontal Object Wave. Move your head, you get different views. Display resolution limitations today. Third Generation. Horizontal and vertical quantized Object wave. Fourth Generation 3D-TV. Record the entire Object Wave. Modulate the Object wave to make it ‘recordable’. Hologram does this. Massive bandwidth needed. Just like natural vision. No eyestrain.
viewer’s eyes Screen RL object at infinity D LR LR object behind screen (positive parallax) V = viewer distance from screen P = Object perceived distance from viewer D = interocular distance, ±6cm L & R = homologous points in left and right eye images P =V/2 V object in front of screen (negative parallax) object in plane of screen (zero parallax) L,R
Recap: The four ITU 3D-TV Levels of Profile 1. Level 1: Send one picture with the two pictures (L, R) mixed. The ‘nothing new needed’ level. Level 2: Send two pictures, but arranged to look like one: over and under anamorphic, side by side anamorphic, offset sub-sampling (checkerboard). The ‘new display but no new STB level’. Frame Compatible Formant. Level 3: SVC type system could be used to ‘top up’ quality as a second step. The ‘new display plus set top box level’. Level 4: Send one (2D) picture plus something: difference signal, depth map. The ‘new display plus set top box level’. Each has advantages and disadvantages in picture quality/cost trade off. Each level receiver accepts all levels below it. A 3D display purchased today can always be made to work with any level.
‘Frame compatible’ LEFT RIGHT LEFTRIGHT Side-by-SideTop and bottom
DVB spec; The Magnificent Eight! DVB 3DTV Frame Compatible Formats 720p@50, 60 - Top and Bottom 1080i@50, 60 - Side by Side 1080p@24 - Top and Bottom 720p@50, 60 – Side by Side 1080p@24 - Side by Side Why so many? There are circumstances where each of them will produce the highest quality results for the viewer
Sub-titles in Phase 1 3DTV Regions and sub-regions are defined which may be assigned different individual disparity values No signaling means: the stream has been coded to provide subtitles intended for 2D Each region can contain one or more sub-regions referenced to that region
What are the options for Phase 2 3DTV? How much ‘more’ do we need for Phase 2? What quality level is needed? – normal ‘HDTV’ for L and R (720p/1280/50,60 1080i/1920/25,24 1080p/1920/25,24)? – 1080p/1920/50,60 For L and R? What compatibility is needed? – 2D HDTV reception? – FC 3D-HDTV reception? – Both? – None (L, R separate) Should there be provision for viewer depth range adjustment? Should there be both broadcast and download options? What sophistication for multimedia is appropriate? Should we wait for HE-AVC?
Is there a risk of eyestrain? Eyestrain is caused when the eyes are asked to do things they do not normally do. There can be many contributory factors; vertical registration, retinal rivalry, and infinity divergence. It can be minimized. But one of them – the need to separate focus and pointing - is fundamental to the stereoscopic process. It can be minimized by careful production grammar. The authors knows of no complete scientific studies to evaluate the risk of eyestrain, and particularly important to understand risks (if any) to young people.
What kind of programmes are right for 3D TV? Particular type of shot composition and camera lens works best. In principle, content which the viewer wants to experience rather than observe. Many effects can lead to ‘non real life’ perception: puppet theatre effect, card- boarding, elongation, giants eye view, cyclorama background.....
3D suits..... Medium shots with wide lenses constrained depth range key object close to screen plane. soap operas? newscasts? close up sports? small canvas events?
How “Good” is 3DTV? Sense of reality Eye discomfort Eye fatigue Residual effects Optimum system Content type We don’t know enough yet
Conclusions 3D-TV can have a lot of impact, but it is not true complete ‘natural vision’. There are limitations. Many elements can cause eyestrain. It can be minimized, but not removed entirely. We must be honest with audiences. Audiences should be cautioned. An optical illusion, which adds apparent depth and volume to the television picture. 3DTV will be a ‘sub-set of HDTV’ for use when it suits the content.
(example from Fujifilm 3D camera information) CAUTION If you experience fatigue or discomfort while viewing 3D images, cease use immediately. A ten-minute break is recommended about once every half hour. Switch to 2D immediately if 3D images still appear double after you have adjusted parallax. Individuals with a history of photosensitive epilepsy or heart disease or who are unwell or suffering from fatigue, insomnia, or the affects of alcohol should refrain from viewing 3D images. 2D display is also recommended for young children (up to the age of about six) whose visual system is still maturing and for individuals with notable differences in vision between their two eyes, who may find it difficult or impossible to observe the 3D effect. Viewing 3D images while in motion may cause fatigue or discomfort. Arial