Yoo Jae Sin

Bio: Yoo Jae Sin is an academic researcher. The author has contributed to research in topics: Motion compensation & Codec. The author has an hindex of 1, co-authored 1 publications receiving 1 citations.

Moving image coding method, especially in relation to hiding data in a multimedia image

Abstract: PURPOSE: A moving image coding method is provided to extract hidden data when necessary after hiding the data in a multimedia moving image using a video CODEC, without increasing an amount of encoded data and a change of picture quality, consequently original data is unnecessary when extracting the hidden data CONSTITUTION: A system extracts a motion vector through a motion compensation and a motion prediction with regards to an inputted image, performs a DCT process for a difference image, and sets initial quantization parameters The system carries out a data hiding process in the quantization parameters, and changes the parameters to recognize whether the data is hidden The system performs a quantization by using the changed parameters The system changes a level value of each block in DCT block units, and hides the data

Method and apparatus for estimating first qp value to encode video

Abstract: A method and an apparatus for predicting an initial QP(Quantization Parameter) value for image coding are provided to enhance the quality of a restored image by accurately predicting an initial QP value of an input image for reaching target bit rate based on the characteristic value. A time/space predicting unit(41) generates a predicted image of an input image. A subtractor(42) generates a residue image by subtracting the generated predicted image from the input image. A converting unit(43) converts the generated residue image from a color space to a frequency space. An initial QP value predicting unit(44) predicts an initial Q P value of the input image corresponding to a target bit rate based on at least one characteristic value of the input image. A quantization unit(46) quantizes the conversion result by using the predicted initial QP value. An entropy coding unit(47) codes the quantization result.