IMAGE COMPRESSION

Image Compression or Processing Related to Digital Television

[Institution Name]

Image Compression or Processing Related to Digital Television

The advent of digital television is a change as radical as that which changed the black to white and colour. It's about getting images better, but does not stop there, but also will open the doors to the future introduction of services never before imagined, such as mobile television reception, interactivity, television to the letter or the services media so fashionable nowadays with the explosion of Internet. The main problem is that analogue TV takes advantage of the fact that in most cases, the signals vary little video to go from one picture element (pixel) to contiguous or at least a dependence exists between them.

In short, the electromagnetic spectrum is wasted. Addition to increasing the number of transmitting stations, interference happens to become a serious problem. radio channels for digital television occupy the same bandwidth (8MHz) that the channels used by the analogue television, but due to the use of techniques of compression image signals and audio ( MPEG ), can accommodate a variable number of programs in television function of the speed of transmission and can vary between a single program of TV HD (high quality picture and sound) to five programs with quality similar to the current technique (G emission standard PAL colour system), or even more programs like quality video. However, initially, it is expected that each multiple channel (multiple channel refers to the ability of a radio channel to host several TV) national or regional coverage includes at least four programs.

A unique integral imaging system is employed as part of a three dimensional television system, allowing the display of full colour 3D images with continuous parallax within a wide viewing zone. Unidirectional integral imaging is a special case of Integral 3D Image, where cylindrical lenses are used instead of a 2D array of micro lenses, thus providing parallax in the horizontal direction only. A significant quantity of digital data is required to represent captured Integral 3D Images.

In this study, an adaptive 3D DCT based compression algorithm for use with full colour unidirectional Integral 3D Images based on sub-sampling of the chrominance components is presented. The planar intensity distribution representing an Integral Image is comprised of 8 pixels for each cylindrical lens in the horizontal direction. The structure of recorded unidirectional Integral Image intensity distribution is such that a high cross correlation in a third domain, i.e. between the bands produced by the recording 1D cylindrical microlens array, is present. This is due to the small angular disparity between adjacent cylindrical microlenses.

To facilitate development of a compression scheme, the unidirectional 3D Integral Image is split into sections of 8 pixels on the vertical direction thus forming a 2D array of 8x8 sub-images. A 3D DCT is used to de-correlates a group of adjacent sub-images from the source intensity distribution data in both inter-sub-image and intra-sub-image dimensions simultaneously.

The number of sub-images involved in a single 3D DCT computation, N, is made variable ...