| 摘要 |
Methods and apparatuses of image encoding and decoding are disclosed. An encoding method comprises performing a wavelet transform on all pixel values in a digital image data to obtain transform coefficients, scaling up said transform coefficients corresponding to each region of interest, said scaling up being performed based on said bit shift value, encoding said transform coefficients to obtain a coded digital image data, and forming a bit stream including said coded digital image data and a header including a ROI coordinate information and said bit shift value, said bit shift value being assigned to each region of interest identified by said ROI coordinate information. A method of image decoding comprises obtaining a ROI coordinate information and a bit shift value from a header in a bit stream including a coded digital image data, said bit shift value being assigned to each region of interest identified by said ROI coordinate information, decoding said coded digital image data to obtain transform coefficients, scaling down said transform coefficients corresponding to each region of interest, wherein said step of scaling down is performed based on said bit shift value, and performing an inverse wavelet transform on said transform coefficients to obtain a digital image data. |
