Device of sample rate conversion for digital image and the method of the same

摘要

The present invention is to provide a device and a method of sample rate conversion for digital image. With the present invention, the alias effect caused by shrinking the image and the blurred effect caused by enlarging the image will be eliminated. The device of the present invention comprises a ratio-adjustable expander used to receive image signal, increase the sample rate of the image M times based on the adjusting ratio for the image to generate a expanding signal; a low pass filter (LPF) used to receive the expanding signal from the expander, filter out the high rate and output the filtered signal; and a fix ratio decimator used to receive the filtered signal, low down the sample rate by N times and generate the output signal. The value of M will be changed with the adjusting ratio while the value of the N is fixed. The LPF includes the factor 1+z-1+ . . . +z-(N-1) and the factor 1+z-1+ . . . +z-(M-1).