An efficient method for DCT-domain image resizing with mixed field/frame-mode macroblocks

This paper deals with the discrete cosine transform (DCT)-domain image resizing as compressed domain processing. Previous DCT-domain image resizing methods assume that all macroblocks are in the frame-mode. We propose an efficient method for DCT-domain image resizing with mixed field/frame-mode macroblocks. This method is developed from the investigation of the DCT-domain image resizing operation through a decomposition of matrix operations, from which we define new downsampling matrices for frame- and field-mode macroblocks. This leads to new frame- and field-mode resizing transformation matrices for DCT-domain image resizing. The proposed DCT-domain image resizing method can be used when there are mixed field/frame-mode macroblocks.