1 / 30

TV pick-up systems

TV pick-up systems. Europe: 25 full-frames/sec 625 lines Pick-up systems: (Orthicon tube family Vidicon - Plumbicon) CCD : optoel. transformation, integration, read-out. Typical CCD Sensor. 600 lines 800 pixels / line 6,6 mm x 8,8 mm surface

tarika
Download Presentation

TV pick-up systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. TV pick-up systems • Europe: • 25 full-frames/sec • 625 lines • Pick-up systems: • (Orthicon tube family • Vidicon - Plumbicon) • CCD : optoel. transformation, integration, read-out

  2. Typical CCD Sensor • 600 lines • 800 pixels / line • 6,6 mm x 8,8 mm surface • 1, 2 and 3 CCD colour camera pick-up systems • mosaic filters • V() + colour opponent • RGB systems

  3. TV camera with three CCDs

  4. Transmission of the tree channels

  5. Signals for TV transmisssion • Signals produced by camera:

  6. White balance • For  () = 1: thus signals normalised • colour mixture curves:

  7. CCD camera responsivity

  8. EBU primaries

  9. Signal processing in a TV Camera

  10. Electronic matrix

  11. Matrixed colour matching functions

  12. Colour rendering with and without matrixing • Original chromaticity: • x: without matrix • +: with matrix

  13. Gamma correction • Characteristics of a CRT tube: • F: normalised tristimulus value • E’: normalised input quantity • s: stray light • h: offset • : approx. 2,2 , thus in camera: =,45

  14. Gamma correction

  15. Corrections in camera • Gamma balance in camera: • Nonlinear amplitude correction: • 80 % - 200 % input range corrected to 80 % - 110 % output range

  16. Clamping & Knee in characteristics: Method for getting highlights

  17. Camera: 3 receptors matrixing clamping gamma balance Receiver: RGB signals Direct connenction between camera and receiver

  18. Luminance - chrominance • Luminance: • before gamma balance • Chrominance signals: • no luminance information: zero for achromatics:

  19. Luminance - chrominance • Luminance from  distorted signal: • based on NTSC primaries and not on EBU • thus luminance signal depends on chroma • Colour difference signals:

  20. EBU colour solid in Y -Chrominance Space

  21. Chrominance signals of surface colours

  22. Chrominance signals • Luminance signal: 0<EY<700 mV • Chrominance signals: -350 mV <...<+350 mV • Inverse matrix in receiver

  23. Signals in TV transmission

  24. Importance of component signals • CCIR 601 standard: • 576 active lines • 720 pixels per line • for 25 frames/s: 31,1 .106 pixel/s • with 8 bits/colour: 248,8.106 bit/s • Gamma pre-correction - L* similarity • helps to decrease number of quanta steps • smaller bandwidth in chrominance signals • differences visualy equidistant

  25. Comparing  and brightness

  26. The composit signal • In PAL, SECAM, NTSC bandwidth = to black & white transmisssion signal • 1 step: Component signals: bandwidth of chrominance signals approx. 1/4 of lum.signal • 2 step: modulation of chrom.signal onto colour carrier (PAL: 4,43 MHz),chrominance + phase • 3 step: Modulated colour carrier added to Lum. signal

  27. Y

  28. One line of a MAC signal Multiplexed analog components

  29. A possible TV system

More Related