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kevinmowers@yahoo.com
Posts: 49
Posted 20:11 Dec 05, 2015 |

JPEG goes through 2 transformations. One is DCT, is the other transformation YCrCb?

vsluong4
Posts: 87
Posted 00:39 Dec 06, 2015 |

Yes, page 5 of lecture notes 10 (JPEG Algorithm) goes over it in slightly more detail

lhairap
Posts: 11
Posted 22:41 Dec 06, 2015 |

Isn't YCrCb the result of applying DCT into RGB image?

vsluong4
Posts: 87
Posted 22:43 Dec 06, 2015 |
lhairap wrote:

Isn't YCrCb the result of applying DCT into RGB image?

no

lhairap
Posts: 11
Posted 23:04 Dec 06, 2015 |
vsluong4 wrote:
lhairap wrote:

Isn't YCrCb the result of applying DCT into RGB image?

no

Oh, that's right. Does YCrCb convert RGB into luminance and chrominance? 

 

Last edited by lhairap at 23:05 Dec 06, 2015.
ggonza83
Posts: 14
Posted 18:21 Dec 07, 2015 |

Correct me if I am wrong here, but isn't the two transformations that happened in JPEG is changing the color scheme from RGB to YCbCr and the second one is sub-sampling? I thought going through DCT was quantization, not transformation. If I am wrong I apologize, I don't want to confuse anyone.

vsluong4
Posts: 87
Posted 10:40 Dec 08, 2015 |
ggonza83 wrote:

Correct me if I am wrong here, but isn't the two transformations that happened in JPEG is changing the color scheme from RGB to YCbCr and the second one is sub-sampling? I thought going through DCT was quantization, not transformation. If I am wrong I apologize, I don't want to confuse anyone.

DCT = Discrete Cosine TRANSFORM 

Quantization is a step that occurs after DCT

Sub sampling is not a transformation

You should really review your notes/the PP