| 摘要 |
For fractal image coding optimal scaling factors for the image contents in the domain blocks are searched. Each image is divided into analysis blocks, which jointly represent the whole image. The analysis blocks are embedded in analysis regions, which contain besides the analysis blocks areas with a predetermined signal value. Also, comparison regions are formed, which contain at least parts of the image and which have the same size as the analysis regions. The analysis regions and the comparison regions are Fourier transformed. The transformed signals are converted logarithmically. The logarithmized signals are again Fourier-transformed. One of these signals is converted in its conjugate-complex form before both signals are multiplied. The product is normalized, so that it no longer contains amplitude information. Then the signal is subjected to an inverse Fourier-Transformation. If the signal has been logarithmized then it is de-logarithmized. The maximum of this signal then indicates the optimum frequency factors. By a further inverse Fourier-transformation the maximum of the signal indicates the optimal scaling factor that is searched.
|
