YIQ by R.Chinthamani.pptx

YIQ

1. YIQ COLORS Submitted By Mrs.R.CHINTHAMANI , ASSISTANT PROFESSOR , Department of Computer Science E.M.G.Yadava Women’s College, Madurai-14 .

2. A color model is a specification of a 3D color co-ordinate system and a visible subset in co-ordinate system within all colors in particular color range. Four types are, R GB, CMY, YIQ, CMYK. COLOR MODEL

3. YIQ model is used for NTSC(NATIONAL TELEVISION SYSTEM COMMITTEE)broadcast. This model was designed to separate chrominance( I and Q ) from luminance Y. This was the requirements in early televisions when black and white set still were expected to pick up and display what were originally color pictures DEFINITION

4. YIQ MODEL

5. Y - luminance I - in phase Q - quadrature YIQ STANDS FOR:

6. The Y –channels contains the luminous information(sufficient for black and white TV) while the I and Q channels carried the color information. The color TV would take three channels Y,I and Q and map the information back to R,G and B levels for display on a screen. YIQ MODEL

7. The more bandwidth can be assigned to Y –component because the human visual system is more sensitive to changes in luminance than to changes in hue or saturation. The YIQ is the recoding of RGB color model. It is used in television broadcasting using one composite signal. ADVANTAGE

8. The ability of separation gray scale information from color data property enables to represent the same signal for both color and (black and white) sets, using luminance component . Used in video system for determining color components because of its human visual system characteristic. The component Y might represent noise in processing, transferring, and storage at shallow level.

9. INPHASE =RED-YELLOW QUADRATURE =BLUE-YELLOW It is based on the CIE and XYZ color model. Broadcast NTSC limits I to 1.3 MHz and Q to 0.4 MHz . I and Q are frequency interleaved into the 4 MHz Y signal, which keeps the bandwidth of the overall signal down to 4.2 MHz .

10. DEGREE OF YIQ COLORS

11. The YIQ representation is sometimes employed in color image processing transformations. For example, applying a histogram equalization directly to the channels in an RGB image would alter the color balance of the Image. Histogram equalization -method in image processing for contrast adjustment . IMAGE PROCESSING

12. NTSC encoding of YIQ : 4 MHz = Y (eye most sensitive to luminance) 1.5 MHz = I (small images need 1 color dimension) 0.6 MHz = Q ENCODING

13. The primary goals of the system were to provide a signal that could be directly displayed by black and white TVs, while also providing easy coding and decoding of RGB signals . GOAL OF YIQ

14. TAXONOMY OF COLORS

15. The color range is restricted in the color TV images because of the information compression required for the displayed image. Due to the limitation of the YIQ standard the image displayed in computer cannot be recreate in TV screen. DISADVANTAGES