FFT-based image compression algorithm optimized for speckle interferometer measurements

In the framework of ESA's FluidPac satellite mission, we have developed a fast, lossy image compression algorithm (ICA) based on a slight variation of the classical 2D FFT. In essence, given a monochrome picture, the ICA calculates its Fourier spectrum. It then applies a low-pass filter to eliminate all Fourier coefficients beyond a certain user- defined cutoff frequency. Finally, it further compresses by encoding the surviving FFT coefficients in more memory- efficient manner. The proposed scheme works best with pictures where the high-frequency data are of little value. This is precisely the case with electronic speckle pattern interferometer images. The ICA's low-pass filter gets rid of the speckle noise while preserving the useful scientific information: the interference fringe pattern. We have, however, also applied the FluidPac ICA to pictures generated by classical interferometers, photographic equipment, particle tracing instruments, and IR cameras. The results are extremely encouraging.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.