Digital solar imaging systems have been widely used in solar observations. Their high resolution, high rate of image acquisition and convenience for off-line image processing have provided significant improvements to solar physics research. In this project, two digital magnetograph systems established at Big Bear Solar Observatory (BBSO) have been described. One is used to provide a high frame rate magnetogram system, and the other provides a real-time image alignment, i.e., a correlation tracker system.

The developed correlation tracker system consists of a high-speed 64x64 CCD camera, an EDT image grabbing board, an agile mirror, a D/A board and a Sun Ultra-30 workstation. Based on the same hardware, digital magnetograph system has been built and tested. The novel correlation tracker system does not use traditional FFT hardware and is more integrated in a Sun Ultra-30. The system software has been developed by using C and Motif graphical user interface under Solaris 2.6. Both systems have been demonstrated to work very efficiently at BBSO.

After tens of thousands of solar magnetograms have been grabbed with the digital magnetograph system, various image processing methods have been studied to improve resolution, eliminate image noise and stray light effect. The efficiencies of different processing methods have been discussed and their Fourier spectra have been analyzed. After noise deduction and stray light elimination, the processed magnetograms have been proved to be much better than the original images.