Design of JPEG image file system in corona detection system

An ultraviolet corona detecting system was proposed for detecting and locating corona,in which TMS320DM642 was used as primary processor.A visible camera and an ultraviolet camera were used for inputing in the system.Two cameras have same visual field,so the processor can compose those input videos,and then display the result on LCD for user easy to observe and locate the corona.The interested images can be captured and saved into the internal FLASH of the system before it is encoded to JPEG files.The images in the internal FLASH can be displayed on LCD or downloaded into PC using USB interface.A kind of JPEG image file system was designed for saving these images,and implementation of JPEG algorithm based on RF5 was discussed.The design of storage space,structure of directory area,and the implementations of basic operations such as initialization,reading and writing in the file system were particularly discussed.The experimental results show that it respectively spends 10.5 ms and 9.6 ms for JPEG encoding and decoding operations on the image of 720×576 resolution,and it spends about 4~6 s for capturing and saving operations,and 70 images can approximately be saved in the file system.