Discrete Cosine Transform (DCT)

Author: Werner Bailer (werner@wbailer.com)
Date: 2001/10/29
Source: DCT_.java
Installation: Download DCT_.class and DCT.class to the plugins folder and restart ImageJ.
Description: Calculates forward and inverse 2D discrete cosine transform (DCT). The DCT class implements the DCT and provides methods for writing coefficients in zig zag order into a 1D array. The DCT_ class is the ImageJ plugin handling user input of parameters and creating a new image showing the result of the DCT/IDCT. The user can set the following parameters:
  • block size (a power of 2)
  • forward or inverse DCT
  • if the image is sclaed to the block size or split into tiles of this size
  • scaling of output (by default [-1,1])
Limitations: Only works with 8, 16 and 32 bit grayscale images.

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