The Research On The Real-time Process Of Low-Light-Level Video Image

The research on low-light-level video image real-time process has important theoretic significance and applied value. For low-light-level video image real-time processor adopting DSP, it is important that DSP and peripheral equipments have high speed and powerful function. TMS320C64xx is specially used in areas of image process and communication. Its main frequency is 1.1GHz. Its processing speed is near to 9000 MIPS, and its whole capability is higher than TMS320C62xx by 10-15 times. So, Using TMS320C64xx in low-light-level video image process is significant to improve the real-time quality of the system, reduce the volume and the power exhaustion of the system.For remove noise from the low-light-level image effectively and improve the contrast of image, software development of DSP in the system of low-li-ght-level image real-time process is mainly researched in this paper. Based on analyzing characteristic of low-light-level image, aiming at the characteristicof low-light-level image, a great deal of noise and low contrast, combining the characteristic of TMS320C64xx, 3×3 median filter algorithm and quick median filter algorithm is ameliorated for the purpose of improving processing speed. Based on the research of TMS320C64xx program and codeoptimization, 3×3 median filter algorithm ameliorated, 5×5 median filter algorithm ameliorated algorithm and histogram equiangular algorithm is realized. The key code effecting process speed is optimized and the effect is good.Transfer of image data is often one of bottle neck of the system. DMA (Direct Memory Access) should be used as often as possible to transfer block data, in order to alleviate the press of data transfer. EDMA (Enhance DMA) is used to realize input and output video data, and a scheme of two buffers is designed for input and output of video data in this paper. QDMA (Quick DMA) is used to transfer image data between extra memory and buffer of inter memory, and a group of function managing image data is designed to package the request of QDMA, which make it easy for programming, maintain and debug.Programming based on real-time operating system, DSP/BIOS, is researched in the last of this paper. DSP/BIOS is a excellent software platform. Simulation of extra hadware interrupt routine, simulation of EDMA transfer of input andoutput of videodata is made on this platform. Analysis of the effect of amelioration and optimization of algorithms are also performed on this platform.