Design And Research Of Hardware System By High-resolution CCD

Panoramic technology became an important topic in the fields of video surveillance, it also had a broad application prospect in the field of computer vision,scientific research, exploration and aerial mapping. At present, the pixels of front-end camera were between250,000～380,000in the panoramic technology, the color resolution was420line, the black and white resolution was about500line. But they could not satisfy high quality image acquisition requirements of HD front camera because pixels of HD front camera were above380,000, the color resolution was greater than or equal to480line, the black and white resolution was above570line.Based on the development of video surveillance and the needs of panoramic technology, this paper designed a kind of CCD video front-end acquisition equipment which has the external synchronization function, it had440,000pixels and550lines’color resolution to deal with the problem of insufficient resolution of front-end camera in panoramic technology so that it could meet the requirements of high resolution in panoramic video surveillance.Through the analysis of system requirements and the comparison of different solution, this paper finally determined to take ICX409AK of SUPER HAD technology as CCD image sensor,on that basis, the special-purpose DSP chip CXD3172AR was taken as core video processor.lt not only had a internal CCD drive and a8-bit DAC so that it could support external synchronization function and short development cycle, but also had video signal processor, external synchronous circuit, EEPROM memory and the power supply unit.The effective pixels of image sensor was752(H) X582(V) in the system, the image was shown as clear as taken by high-ranking video monitoring CCD; the video signal processing chip CXA3796N belonged to IC grade,it had a related double sampling circuit and a wide range of adjustable and programmable gain amplifier, it could reduce and amplify original video signal; EEPROM could be erased and written repeatedly, it was used to store the special-purpose DSP firmware program and the selection of system operation mode;Using the tracking function of phase lock loop phase, phase locked loop circuit was designed to achieve that local video signal synchronized with external synchronous signal phase; For CCD’s strict requirements to voltage, the power supply unit reduced the system power12V to3.3V through the voltage conversion chip, and to5V through the linear power supply. And considering the problems of cabling, volume and external synchronous signal mutual interference at the same time, the image acquisition and synchronization circuit was used to separate on the two pieces of PCB, it improved the reliability of the system.The drive signal and the video signal met the requirements of chip manual through the system function test, and the collected display images were clear, stable,and less defects, it had50fps/s.Through observing the monitor and comparing the external synchronizing signal waveform in oscilloscope with video output signal waveform, we found that two CCD cameras scanned images with homo-frequency and steady video phase difference was within the fixed10μs, it achieved the function of drive clock synchronous external clock in one frame period. Meanwhile based on the research on test method of the electronic camera resolution, we set up a test platform for testing the spatial resolution of HD front-end camera system, the results were showed that the system had a higher image resolution, which met the design of high quality image acquisition, and had higher application value and research significance.