Research On The System Of Scanning Core Images By The High Resolution Linear CCD

Core is the most valuable material for the study of geological information.At present,the core has been able to achieve digital collection an d preservation through the core scanner.But the exis ting core scanner has the problem of low im age resolution and high price.For the demand of improving the resolution and reducing the cost in application,the paper carried out the research of high resolu tion core scanning im aging system based on linear array CCD.The main research work of this paper is as follows:Firstly,lens is the necessary part of the image acquisition system.However,due to the inherent optical properties of the lens,th e acquired im ages have a certain degree of distortion.Aiming at this problem,the paper st udied and improved the black and white chess board coordinate m ethod,and applied it to the im age distortion correction.The experimental results show that the m ethod can effectively correct the distortion of the pillow;Due to the linear array CCD was used to obtain the two-dimensional image must use the motion of the external motor,but motor velocity and CCD line scanning does not match will m ake the im age distortion.Based on "the principle of the square," th at the vertical resolution and horizontal resolution in the case where the image will not produce equal distortion correction m otor speed,so th at the CCD line f requency match with each other,thereby correcting the image distortion caused by the movement of the motor.Secondly,the image quality of the core sca nner imaging system is determined by the analog front end of the linear ar ray CCD to a certain extent.For the problem of existing CCD timing driver circuit and data buf fer circuit of the analog front end module anti-interference ability is weak,the output data is not effective buffer and so on,the paper improved the design of the tim e sequence driving circuit and the data buf fer circuit.Simulation and experimental results show that the improved circuit can effectively improve the ability to resis t interference,and the output data can be ef fectively buffered and impedance matching.Thirdly,owing to the line CCD image with intensity inhomogeneity,more noise,it inevitably affects the image quality,the paper corrected the gray level o f the core im age using two points m ethod.The experimental results show that the gray level of the core image is corrected by two point method;In addition to the salt and pepper noise image,the paper studied and improved the traditional median filtering algorithm.The times of finding the median number reduced to 18 tim es and the improved median filtering algorithm is realized on FPGA.The experimental results show th at the im proved median filtering algorithm can effectively restrain the salt and pepper noise.It can be seen from the experimental results that the line array CCD core scanning imaging system has ach ieved the core im age acquisition,the im age resolution reached 4718 DPI,and the system input cost is low.