| The MTF (Modulation Transfer Function) of an optical remote sensing imagingsystem is one of the most important indicators to measure the performance of theimaging system, since it reflects the capability of the system to acquire detailinformation of targets or scenes. However, when an imaging system is used to capturean image, due to the effects of optical system, atmosphere, electrical system and therelative motion between target and imaging system, the system MTF is attenuatedseverely to blur the scene s high-frequency information, resulting in blurred images.Therefore, seeking for an effective method to compensate the MTF of an opticalremote sensing system has been becoming a challenging and attractive researchtheme.Vary from the conventional MTF restoration methods based on digital imagepost-processing technique, a brand new MTF compensation approach is proposed inthis paper. According to the Fourier optics theory, an ordinary optical remote sensingimaging system is a low-pass filter in spatial domain. So taking use of the boostingphenomenon of the second-order analog low-pass filter around its cut-off frequency,the magnitude of the target frequency region of the MTF which is decreased by thesystem can be amplified. Based on this theoretical analysis, the online MTFcompensation system is designed. Meanwhile, the analysis of the parameters of thecompensation system and the performance of the hardware circuit system is described.Both the theoretical analysis and experimental results have proved the validity of theMTF online compensation technology.The main contents of this paper include the following aspects:Firstly, by means of researching the physical principle of the imaging processand analyzing effects of the MTF of optical remote sensing systems, amathematical-physics model of typical optical remote sensing imaging systems is discussed.Secondly, the requirements of a compensating system for MTF should meet wereproposed and the feasibility of the online MTF compensation system was confirmed.In addition, how to determine the key parameters while designing a MTFcompensation system and the way to evaluate the performance of the correspondingcircuit are described in this paper.Thirdly, simulation models of both remote sensing imaging system and MTFonline compensation system are established with MATLAB software according to thephysics-mathematical model of remote sensing imaging system and the principle ofthe MTF online compensation technology. Several simulation experiments wereoperated to analyze and evaluate the performance of the MTF online compensationsystem. Furthermore, the circuit of the compensation system was tested using PSPICEcircuit simulation software. |
PDF Full Text Request