Abstract:The solar magnetograph is a key instrument for observing and studying the solar magnetic field, and the image correlation system of the magnetograph directly is one of the key technologies in the instrument, affecting the accuracy and spatial resolution of the data. In view of the strict requirements of the deep space exploration satellite system on the weight and size restrictions, an image self-correlation system for space solar magnetograph was designed. The system contains the accurate polarization modulation, accurate alternating sampling control and image correlation algorithm, to overcome image blur caused by satellite platform jitter, to realize the image real-time correlation, so as to obtain higher resolution solar magnetic field data. The system adopts modular design and mainly includes six parts: camera and KD*P high-voltage control, image data conversion, communication function on FPGA (Field-Programmable Gate Array), image correlation, communication function on DSP (Digital Signal Processor), and control system. The solar magnetic field data can be obtained by one button through the control system software. At present, the real-time image correlation observation function (20 frame/s and 1 Ktimes1 K area array) is realized based on FPGA + DSP architecture, and achieve stable accuracy within 1 pixel. On June 18, 2021, the ground experimental test was carried out on the 35-cm solar magnetic field telescope in Huairou solar observing station. The data results show that the image self-correlation system can effectively correct and integrate the image offset in real time, and obtain higher resolution solar magnetic field data. In addition, the system does not depend on the hardware devices such as the deflection mirror in the traditional image correlation system, and can be directly embedded into the onboard data acquisition system, to reduce the weight and power consumption of the system, and improve the reliability of the on-orbit operation.