Report no.-01

A report on

3D technology and

applications in television

table of contents

PAGE NO.

Acknowledgements

Preface

1.Introduction 1

2. Technical Aspects of 3D television 2

2.1 Content Generation 3

2.1.1 Stereoscopic Dual Camera Approach 3

2.1.2 Depth Cameras 5

2.1.3 2D to 3D Video Conversion Approach 7

2.1.4 Multiview Video camera Approach 8

2.2 Coding And Transmission 9

2.2.1 General Methods 10

2.2.2 Depth Based Coding 11

2.2.3 Multiview Video Coding 11

2.2.4 Multiview Video plus Depth Coding 11

2.3 Display 11

2.3.1 Binocular With Glasses 12

2.3.1.1 Anaglyph 12

2.3.1.2 Polarisation Tech. 13

2.3.1.3 Alternate Frame Sequencing 15

2.3.1.4 Spectrum Filtered-Dolby 3D 16

2.3.2 Auto-stereoscopic Displays 17

2.3.2.1 Parallax Barrier 18

2.3.2.2 Lenticular Systems 19

3.Global Reception 20

4.Health Effects And Criticism 24

List of

Illustrations

FIGURES PAGE NO

.

1.FIGURE 1 04

2.FIGURE 2 06

3.FIGURE 3 07

4.FIGURE 4 14

5.FIGURE 5 14

6.FIGURE 6 15

7.FIGURE 7 17

8.FIGURE 8 18

9.FIGURE 9 20

10.FIGURE 10 21

TABLE

TABLE 1 22-24

Abstract

This report deals with the general aspects of the working of a 3D television.it includes the

making of 3D,its conversion from 2D,the popularity in the present world and the criticism it

has faced.it also explores the various scopes for development of 3D and its presumed

dominance in film-making and mass media.

Copyright 2012

All rights reserved.

No part of this publication can be reproduced or published in any form or by any means,or

stored in a database or retrieval system without prior permission in writing of the publisher.

1. INTRODUCTION:

Television is one of the most popular distance-communication media that

basically captures, transmits and displays moving images with or without an

associated sound. In the very early stages of its development, television

employed a combination of optical, mechanical and electronic technologies to

capture, transmit and display a visual image. But, by the late 1920s, those

employing only optical and electronic technologies were being explored and

that was the primitive model for all the modern television systems.

The inability of transmitting direct light signals over large distances, and the

then recently developed telephone paved the way for the development of the

method of “scanning”. And the television was also called “telephonoscope”.

This idea of scanning, on further research led to the concept of “rasterisation”,

which is presently the key part of capturing a visual image and its subsequent

transmission. But, in initial days, only stationary images could be processed in

this way until the Nipkow disk demonstration of John Logie Baird in 1926

marked the beginning of display of moving images on television.

From then, the television has undergone many evolutionary changes, in rather a

short period of time. Taking into account only the technical details of the

development of television, the major milestones involved are SDTV(Standard

Definition Television),EDTV( Enhanced Definition Television),and very

recently, the HDTV(High Definition Television). The latest in the hierarchy is

the 3D TV(Three dimensional Television) which is the topic being discussed in

this report.

A 3DTV is a combination of the features of a 3D motion picture and a HDTV.

Though the pioneers of television and 3D motion picture have been doing their

research in these fields for approximately the same period of time, it is only in

the early 21st century that a 3DTV could actually be developed. In this report we

present the basic characteristics of a 3D film and how it was adopted in the

research of television to make a 3DTV. The discussion includes the details of

various technical details only of 3d film, and their association with the general

concepts of television.

2. TECHNICAL ASPECTS OF 3D TELEVISION :

A 3-D television system works with the combination of features of a 3-D

motion picture and general television broadcasting. Broadly, a television

broadcasting process consists of three major stages, content generation, coding

and transmission and display. In the case of a 3-D television, the content

generation and display aspects are very much influenced by the concepts of 3-D

motion picture while the transmission aspect is essentially very much similar to

that of general HD television.

2.1.CONTENT GENERATION:

Currently there does not exist any industry-wide accepted mastering standard

regarding the format of 3D content. The industry fragmentation and lack of

standardization in this particular aspect of production has hold back the

development of 3D technologies. Standardization is one of the key components

needed for the successful development and employment of 3D.

In general, there are four types of 3D content generation as shown in Figure 1.1:

i) the stereoscopic dual-camera approach, which results in two separate views

(left and right), ii) the 3D depth-range camera approach, which generates a 2D

image plus a depth map, iii) the 2D-to-3D video conversion approach, which

converts existing 2D video material into stereoscopic 3D by estimating a depth

map from the 2D video sequence and subsequently rendering the left and right

sequences, and iv) the multi view video camera approach. The following

subsections present an overview of the different schemes for 3D content

generation.

2.1.1. STEREOSCOPIC DUAL CAMERA APPROACH:

In stereoscopic videos, the function of the retinas in the visual system is

mimicked by the lenses of two identical synchronized cameras, which record

the left-eye and the right-eye views from two slightly different perspectives (see

Figure 1.3). Then, when the viewer watches stereo videos, the recorded right

and left view images are projected on the viewer’s eyes and the brain

reconstructs the third dimension by combining the received visual information.

The configuration of the cameras can be parallel (with axial offset of the

imaging sensor) or toed-in (where the cameras are angled in). However, to

eliminate keystone distortion and depth plane curvature, the parallel camera

configuration is preferred.

Figure 1- A stereoscopic camera setup

The production of stereoscopic dual-camera video is highly demanding. Two

cameras should be configured so that the contrast, brightness, colour, and

sharpness of captured images are the same or within a very tight tolerance to

prevent eyestrain and headache for the viewer. In addition, the cameras need to

be properly calibrated so that the disparity introduced to the viewer is similar to

the one he/she receives from the actual scene. This consensus should be

satisfied even when visual effects such as zoom-in or zoom-out occur. This is

very challenging in the case of 3D. For example, an increased zoom-in may

break the 3D effect in the sense that viewers become unable to fuse the right

and left view images.

2.1.2. DEPTH CAMERAS:

The operation of the camera is based on generating a “light wall” moving along

the field of view, see Figure 2. As the light wall hits the objects, it is reflected

towards the camera carrying an imprint of objects. The imprint contains all the

information required for the construction of the depth map. The 3D information

can now be extracted from the reflected deformed “wall” by deploying a fast

image shutter in front of the CCD chip and blocking the incoming light as

shown in Figure 2c. This type of camera belongs to a broader group of sensors

known as scanner-less LIDAR (laser radar without mechanical scanner). The

collected light at each of the pixels is related to depth, but also to the reflectivity

of objects. Hence, a normalization step is performed per pixel by simply

dividing the front portion pixel intensity by the corresponding portion of the

total intensity.

Figure 2- Operation of a depth camera

The technological challenge of the depth camera is twofold: Fast switching of

the illumination source to form the “light wall”, and fast gating of the reflected

image entering the camera. In the current depth camera, a cluster of IR laser

diodes and corresponding optics is used to generate homogeneous illumination.

The diodes are switched on and off with rise/fall times shorter than 1

nanosecond. None of the existing fast drivers and switchers was suitable for our

extreme application. Hence, super fast driver electronics had to be designed to

comply with the fast response, small space and low cost, and yet maintain high

efficiency. The detection of the reflected pulse has to be synchronous with the

switched illuminator. For this, a special fast driver has been designed that has

rise/fall times shorter than 1 nanosecond. The current camera uses a fast optical

switch on the basis of a so-called gated intensifier. This device is pixelized and

contributes a small amount of noise, which limit the depth resolution and

accuracy respectively.

Figure 3- 3D depth range camera

2.1.3. 2D TO 3D VIDEO CONVERSION APPROACH:

It is widely accepted that the success of the 3D technology and its market

penetration will directly depend on the availability of 3D content. It is probably

not realistic (in the introduction phase of 3D TV) to assume that the need for 3D

content can be satisfied only with new-recorded materials. One alternative

solution is the conversion of existing 2D popular movies and documentaries

into 3D format to be watched on 3D screens. Successful implementation of such

an approach will also create a new market opportunity for content owners and

providers to resell their existing products. It is because of these reasons that 2D

to 3D conversion has recently received a lot of attention by the research and

industry communities. Converting 2D content to 3D video streams is possible if

the depth information is estimated from the original 2D video sequence. Having

the depth information along with the 2D video, 3D video content can be created.

Conversion of existing 2D video materials to 3D is a very challenging task.

Depth map estimation techniques try to use monocular depth cues and imitate

the human visual system when estimating the distance between objects. The

difficulty of this task is the absence of the binocular parallax information, which

is the most dominant cue for depth description. Depth map estimation

techniques generally fall into one of the following categories: manual, semi

automatic and automatic. For the manual methods, an operator would manually

draw the outlines of objects that are associated with an artistically chosen depth

value. As expected, these methods are extremely time consuming and

expensive. For this reason, semi-automatic and automatic techniques are

preferred for depth map estimation.

2.1.4. MULTIVIEW VIDEO CAMERA APPROACH:

The multiview video camera approach involves capturing the scene from

multiple viewpoints with a setup of N synchronized cameras. The configuration

concerns of this approach are similar to those of the stereoscopic dual-camera

approach, with the exception that there are N synchronized cameras rather than

two. In this case, several people can watch 3D videos from slightly different

viewing angles. Ultimately, we would like to offer the viewer the opportunity to

choose his/her preferred viewing angle (free viewpoint TV). To achieve this, we

need to have a high camera density (large N) and the ability to accurately

interpolate any possible view in-between using certain camera parameters. In

general, the quality of the intermediate views increases as the number of

available cameras increases. This is because more original image information

becomes available as the number of cameras increases. On the other hand, the

use of more cameras increases the capturing and processing expenses but

improve the quality of the interpolated views (an obvious trade-off between cost

and quality).

2.2. CODING AND TRANSMISSION:

Coding and transmission plays a key role by acting as a bridge between the

generation and display aspects of a 3D television system. Efficient coding and

the subsequent transmission become indispensable for the success of the 3D

television system. Without proper transmission, the original image or video may

be damaged when it reaches the display phase. Despite the presence of

similarities between the general coding and the coding in the case of 3D

television, the case of the latter involves many complicated features, as it

involves high range electronics. So, in this section we just mention the

techniques of 3D coding under three categories, after briefly outlining the

general methods of transmission.

2.2.1. GENERAL METHODS:

The basic requirement of a separate coding mechanism for transmission is the

inability of the intended light and sound signals to travel from the place of

generation to the place of utilization. Naturally, the generation stations are

situated at large distances to the places of broad cast and thus this aspect of the

problem of transmission is unavoidable. Therefore it becomes important for the

employment of proper techniques for the purpose of making the light and sound

signals without much attenuation.

Television signals can be sent over the air, through an antenna or satellite dish,

or through a network of cables, as with cable television. In the case of antenna

for example, signals are sent from a radio broadcast tower. In a cable

transmission, signals are transmitted as electrical pulses and they travel much

further distances than radio waves.

Modulation is a very important term concerning transmission. It is the

phenomenon of mixing the intended signal with a high frequency signal (in

general) and transmitting it so that it does not get attenuated over very long

distances. The wave on which the signal to be transmitted is superimposed is

called the carrier wave. There are several ways of modulation. Amplitude

modulation, for example, is the method in which the amplitude of the carrier

wave is varied in accordance with the modulating signal.

In the case of 3D coding and transmission, the signals to be transmitted are not

mere light, additional factors like the depth coordinate associated with every

point in the image also need to be encoded and accordingly transmitted. There

are three ways with which this is done.

2.2.2. DEPTH BASED CODING:

The depth-based coding targets 3D content in the form of 2D video plus depth

recorded by depth-range cameras or generated by 2D to 3D video conversion

techniques.

2.2.3. MULTIVIEW VIDEO CODING:

The multiview video coding targets stereoscopic 3D (two views) and multiview

video content.

2.2.4. MULTIVIEW VIDEO PLUS DEPTH CODING:

Multiview video plus depth coding focuses on compression of multiview videos

and the corresponding depth maps.

2.3. DISPLAY:

All of the present day 3D display technologies exploit the physiological aspect

of our visual system by creating the illusion of depth by presenting a different

image to each eye. While some of these methodologies employ the usage of

separate lenses to get the 3-D perception, some others do not do so. Based on

this there are mainly two major types of display for the purpose of 3-D viewing.

2.3.1. BINOCULAR WITH GLASSES:

2.3.1.1. ANAGLYPH:

Anaglyph images were the earliest method of presenting theatrical 3-D motion

pictures. In an anaglyph, the two images are superimposed in an additive

light setting through two filters, one red and one cyan. In a subtractive

light setting, the two images are printed in the same complementary colours on

white paper. Glasses with coloured filters in each eye separate the appropriate

images by cancelling the filter colour out and rendering the complementary

colour black.

Anaglyph images are used to provide a stereoscopic 3D effect, when viewed

with glasses where the two lenses are different (usually chromatically opposite)

colours, such as red and cyan. Images are made up of two colour layers,

superimposed, but offset with respect to each other to produce a depth effect.

Usually the main subject is in the centre, while the foreground and background

are shifted laterally in opposite directions. The picture contains two differently

filtered coloured images, one for each eye. When viewed through the "colour

coded" "anaglyph glasses", they reveal an integrated stereoscopic image.

The visual cortex of the brain fuses this into perception of a three dimensional

scene or composition.

Figure 4- Anaglyph glasses Figure 5- An anaglyph picture

2.3.1.2. POLARIZATION TECHNIQUE:

Polarization-based displays separate left and right eye images by means of

polarized light. Left and right output channels (monitors or projectors) are

covered by orthogonally oriented filters, using either linear or circular

polarization. The polarized stereo images are projected and superimposed onto

the same screen. The observer needs to wear polarized glasses to separate the

different views again. When watching with glasses, since each lens passes only

the light that is polarized in its polarizing direction and blocks the light

polarized in the opposite direction, each eye sees its matching image and the

observer perceives depth effect.

Linear polarized glasses use vertical polarization on one lens and horizontal

polarization on the other (see Figure 6). The 3D effect is perceived as long as

the user’s head is kept straight. Tilting the head will break the 3D effect and

some amount of ghosting or crosstalk may occur. Circularly polarized lenses are

polarized clockwise for one eye and counterclockwise for the other (see Figure

6). This method of polarization will maintain the 3D effect if the head is tilted.

The polarized-based display system offers good quality stereoscopic imagery,

with full color rendition at full resolution, and very little crosstalk in the stereo

pairs. It is the system most commonly used in stereoscopic cinemas today. The

most significant drawback of this kind of system is the loss of light output due

to the use of polarizing filters (which is more evident in circular polarization).

Figure 6- Linear and circular polarizations

2.3.1.3. ALTERNATE FRAME SEQUENCING:

This is the current method of choice for most 3D television companies. In this

method, the media is displayed at a high frame rate, and the glasses rapidly

switch between black and clear using a pair of low-latency transparent LCD

screens. These are called “active shutters”. In this way, one eye sees nothing

(for as little as a hundredth of a second or so) while the other sees its “correct”

image, and a few microseconds later, the situation is reversed: the opposite

eye’s image is displayed and the LCDs have switched. The benefit is that each

eye is getting the full image in its particular turn.

Generally, the active shutters are made up of liquid crystal and they act in

conjunction with a display screen to create the illusion of a three dimensional

image. Each eye's glass contains a liquid crystal layer which has the property of

becoming dark when voltage is applied, being otherwise transparent. The

glasses are controlled by an infrared, radio frequency, DLP-link or a blue

tooth transmitter that sends a timing signal that allows the glasses to alternately

darken over one eye, and then the other, in synchronization with the refresh

rate of the screen. Also, LC shutter glasses mostly eliminate "ghosting" which is

a problem with other 3D display technologies such as linearly polarized glasses.

Moreover, unlike red/cyan colour filter (anaglyph) 3D glasses, LC shutter

glasses are colour neutral enabling 3D viewing in the full colour spectrum.

Figure 7- An LCD active shutter pair.

2.3.1.4. SPECTRUM FILTERED -DOLBY 3D:

Dolby 3D uses Infitec technology which stands for interference filter

technology. This system encodes left and right images by projecting each with a

differently filtered spectrum of light. In this case the light is filtered differently

for each view, but both the left and right spectrums appear as white light or

near-white light (Figure 8). This differentiates Infitec from the anaglyph method

which uses red filters for one eye and blue filters for the other. In Dolby’s

implementation, the light path in the projector is modified with a filter wheel to

achieve spectral division of the stereoscopic images (see Figure 8). Prior to

projection, some colour-balancing is applied to the image signal inside Dolby’s

digital cinema server.

Complementary spectral division glasses are worn by audience members for

decoding the images so that left eye images are seen only by the left eye, and

right eye images are seen by only the right eye. To accomplish this, Dolby’s

glasses employ some 50 layers of thin-film coatings to create the appropriate

optical interference filters.

Figure 8- Dolby-3D

2.3.2. AUTO- STEREOSCOPIC DISPLAYS:

Auto-stereoscopic displays apply optical principles such as diffraction,

refraction, reflection and occlusion to direct the light from the different

perspective views to the appropriate eye, allowing multiple users to watch 3D

content at the same time without wearing specialized 3D glasses. This property

makes them the best candidate for future consumer 3D TVs. One of the

drawbacks of this system is that the resolution for each view drops as the

number of views increases. The arrival of high resolution flat panel displays has

made multi view applications more feasible. The other important drawback of

these systems is the fact that only under a limited horizontal viewing angle the

picture will be perceived correctly. Historically, the two most dominant auto

stereoscopic techniques are based on parallax barriers and lenticular arrays, and

these techniques are still popular today. The following subsections elaborate on

parallax barriers and lenticular lenses.

2.3.2.1. PARALLAX BARRIER:

Parallax barrier displays are based on the principle of occlusion, where part of

the image is hidden from one eye but visible to the other eye. As it can be

observed in Figure 9, at the right viewing distance and angle, each eye can only

see the appropriate view, as the other view is occluded by the barrier effect of

the vertical slits. Different implementations of this principle are available,

including parallax illumination displays (where the opaque barriers are placed

behind the image screen) and moving slit displays (use time-sequential instead

of stationary slits). The main advantage of these displays is their backward

compatibility in a sense that they can be switched to a 2D display mode. It is

imperative that 3D television technology should be compatible with

conventional 2D television to ensure a gradual transition from one system to the

other.

Figure 9- Parallax barrier display

2.3.2.2. LENTICULAR SYSTEMS:

Lenticular systems are based on the principle of refraction. As it can be

observed from Figure 10, instead of using a vertical grating as with parallax

barrier displays, an array (or sheet) of vertically oriented cylindrical lenses is

placed in front of columns of pixels, alternately representing parts of the left and

right eye view. Through refraction, the light of each image point is emitted in a

specific direction in the horizontal plane. In what is known as the sweet spot of

a display, left and right images can be delivered to the correspondent eye to

create a 3D effect. Older and less sophisticated systems required the viewer to

sit at a specific distance and angle in order to properly view the image and avoid

headaches and eyestrain. Current lenticular lens systems have corrected this by

using a slanted lenticular sheet, allowing up to eight viewers to observe a 3D

image with no ill effects.

Figure 10- Lenticular display

3. GLOBAL RECEPTION:

Television being one of the most successful “mass” media, the development of

television was one of the most popular achievements in the technical and

research history. In fact, it was highly desired at various times of history, that a

new model of television may be developed. Accordingly, the monochromic

(only black and white) televisions of the initial day were mutated into colour

televisions, which were further transformed into High Definition Televisions

and more recently, the 3D televisions. 3D viewing being the most natural

experience of vision, it was always dreamt of being able to watch a daily

programme with 3D effects on a television, instead of going to a 3D motion

picture theatre for the purpose. Thus there was a large scale research in this

particular field alone and tremendous developments have by far taken place.

The reception of the public is, however a moderate one owing to the financial

constraints associated with the present day 3D television. It is worthwhile to

notice that the 3D television is still in its rudimentary form and researches are

being done to make it an economically feasible product, by trying to enhance

various aspects, for instance, the display mechanism.

The following table gives the information of 3D supporting television channels

in various countries of the world.

Channel Country(s) Additional info.

HIGH TV 3D Worldwide Entertainment

WildEarth Worldwide Wildlife

n3D United States DirecTV only

Cinema 3D United States DirecTV only

3net United States DirecTV only

Sky 3D United Kingdom and Republic of

Ireland Sky only

Foxtel 3D Australia Foxtel only

HD1 Belgium (and other European

countries) Free-to-air

Sky 3D Germany and Austria Sky Deutschland only

Anixe 3D German-speaking countries Free-to-air

3D-TV Finland

Sport 5 3D Israel

Sky 3D Italy Sky Italia only

MSG 3D United States Cablevision only

nShow 3D Poland ITI Group only

ESPN 3D United States

Xfinity 3D United States Comcast only

Penthouse 3D Europe

Canal+ 3D France Canal+ only

Canal+ 3D España Spain Canal+ only

NEXT Man 3D Poland

NEXT Lejdis 3D Poland

NEXT Young 3D Poland

Active 3D India Videocon d2h only

BS11 Japan

RedeTV! Brazil

Viasat 3D Sweden Viasat only

Brava3D Europe Free-to-air

Teledünya 3D Turkey Teledünya only

Sky 3D South Korea SkyLife only

Sukachan 3D169 Japan SKY PerfecTV! Only

TV Azteca 3D Mexico Free-to-air

Chinese 3D Test

Channel China

Made up by 6 different TV

networks

Table 1

We can observe from the above table that the highest incidence of 3D

supporting television channels is in USA and that there is a lot of recognition to

these systems in the European countries. In countries such as India and China,

there is only a single channel capable of 3D viewing. In addition it should also

be noted that these channels can be watched only in the presence of the requisite

hardware such as glasses, 3D compatible television system, etc.

4. HEALTH EFFECTS AND CRITICISM:

Most of the cues required to provide humans with relative depth information are

already present in traditional 2D films. For example, closer objects occlude

further ones, distant objects are de-saturated and hazy relative to near ones, and

the brain subconsciously "knows" the distance of many objects when the height

is known (e.g. a human figure subtending only a small amount of the screen is

more likely to be 2 m tall and far away than 10 cm tall and close). In fact, only

two of these depth cues are not already present in 2D films: stereopsis (or

parallax) and the focus of the eyeball (accommodation). 3D film-making

addresses accurate presentation of stereopsis but not of accommodation, and

therefore is insufficient in providing a complete 3D illusion. However,

promising results from research aimed at overcoming this shortcoming were

presented at the 2010 Stereoscopic Displays and Applications conference in San

Jose, U.S. Motion sickness, in addition to other health concerns, are more easily

induced by 3-D presentations. Film critic Roger Ebert has repeatedly criticized

3-D film as being "too dim" (due to the polarized-light technology using only

half the light for each eye), sometimes distracting or even nausea-inducing, and

argues that it is an expensive technology that adds nothing of value to the

movie-going experience (since 2-D movies already provide a sufficient illusion

of 3-D). Director Christopher Nolan has criticised the notion that traditional

film does not allow depth perception, saying that 95% of our depth cues come

from occlusion, resolution, colour and so forth.

CONCLUSIONS

1. This report is about the different aspects of video broadcasting in a 3D

television.

2. We first outlined the general structure of a 3D video broadcast as three

phases-content generation, coding and transmission and display.

3. We studied various methods involved in the 3D content generation,

especially the direct 3D videography using depth cameras and the 2D to

3D conversion techniques.

4. The general information on transmission is provided and the methods in

the case of 3D television were very briefly discussed. The fact that

additional details like depth coordinate are to be taken into consideration

and accordingly coded for and transmitted, is emphasized.

5. The methods of anaglyph, polarization, spectrum filtered glasses, active

shutters, etc. are discussed in detail. Their importance in the display stage

of 3D television is noticed.

6. The recognition this product has got by far, is noted. The underlying

health effects and the general criticism are also observed.

Bibliography

The internet sources used are-

1.www.google.com

2.www.wikipedia.org

3. www.circle.ubc.ca/bitstream/id/86690/ubc_2010_fall_talebpourazad_mahsa.pdf

4.www.ehow.com

5.www.techcrunch.com

The book sources used are-

1.“Game Physics”,Morgan Kaufmann,

Eberly, David H,Massachussets,2003

Index

A L

Amp modulation 10 Lenticular arrays 18

Anaglyph 12 LIDAR 5

Active shutters 15 M

Accomodation 24 Multiview video camera 8

C Motion sickness 24

Conversion approach 7 P

CCD approach 5 Parallax barriers 18

D Polarisation Tech 13

Depth Camera 5 S .

DLP Link 15 Steropsis 24

Depth map 8 Spectrum filtered 16

Dolby 3D 16

Depth based coding 11

G

Ghosting 14

K

Keystone distortion 4