i wonder why HSV and YUV are different formats, even though they both works similarly (based on the brightness), if not what is the difference and i have confusions with YPbPr and YCbCr , can anyone give directions to understand these color formats.
So the best discussion I can point to is in this PDF on Charles Poynton's site.
The PDF goes on to much more detailed explanations of each color space, and how to convert between them. It's a bit longer than I want to type out (or cut-and-paste images of). :-)
YUV is basically a member of the television industry video-image color formats and was created during the transition of black & white broadcast into color. A compatible color broadcast was needed that could still be received by the existing B&W receivers, yet could also enable color reception with (then) new color TV receivers. The broadcast systems PAL (ENG-GRM) and NTSC (USA) were using color space encodings defined by YUV (or YIQ).
The very successful installment of YUV into the existing commercial TV base has naturally led to its adoption into digital TV systems too; MPEG-I, MPEG-II, and MPEG-IV are all based on digital variants of YUV color spaces. Moreover, the most wide spread image compression codec, JPEG, also uses (digital) YUV variant.
YUV is quite easily obtained from RGB by a simple matrix transform. Y represents the approximate black and white (or luminance) information, and U-V carry the chroma information. The angle between (U,V) pair at a pixel, being the hue and the magnitude being the saturation. U and V components are AC signals, without DC.
HSV (Hue, Saturation, Value) is not that easy to obtain via a simple matrix transform from RGB values. It is suitable for color photography science and It's not a broadcast friendly format and hence not used there.
YPbPr is a variant of analog YUV video color format. Where the Y component is similar to YUV, but Pb is the blue difference and Pr is the red difference channel. It's used in High-End monitor equipment for high resolution (high bandwidth) analog video input, which is worse than pure RGB but better than composite CVBS video.
YCbCr is a digital variant of YUV (probably YPbPr in essence). It's obtained by sampling the corresponsing analog format. There are so many variants that it's hard to refer to the specific one from memory.
You shall consult TV broadcast engineering books for more tabulated answers.
YUV, YPbPr and YCbCr are all basically same, but just with different scale factors for the signals. YUV signals are used when encoding/decoding analog composite video, YPbPr signals exists at analog component video interface and YCbCr signals are digital numbers. There is brightness (luma) channel Y and two color difference signals (U and V, Pb and Pr, Cb and Cr). If you only look at color, color is representend by U and V in cartesian X-Y coordinates on a plane. The HSV system represents color as hue and saturation, which corresponds to polar coordinates in the plane, hue being the angle and saturation being the distance from origin.