Evaluation Method Research Of Overall Performance For Infrared Imaging And Observation System

Infrared imaging and detection techniques are the two most active research areas innow days, the Infrared Imaging and Observation System (IIOS) with thermal imager asits main component is widely used in thermal reconnaissance, warning and guidancearea. The infrared imaging and observation system is composed of target source,transmission channel, thermal imager and observer. The basic physical process ofinfrared imaging system is converting the thermal radiation of scene to thecorresponding output image, which should pass through many stages such as theatmosphere media, optical components, detectors, electronic components, displaydevice, and human eye, etc. The overall performance is the all-in-one specification usedto describe the image quality and estimate field performance of the infrared imaging andobservation system. The Overall Performance Evaluation Model is used to study thequantitative relationship between the target delectability (at different distance) withimage quality and vision acuity.Infrared imaging technique has pass stages of one-detector scan, multi-detector scan,to the staring array and multi-band imaging now days. The performance theory for earlyscan imager is well enough. With the quickly progress of FPA(Focal Plane Array)imager technique, the sensibility or Signal to Noise Ratio has promote a large amount,but the resolution is not enough, and give rise to non-uniformity also, then the earlymodel is neither broadly nor precise enough. The technique of overall performanceevaluation and target detestability performance analysis for infrared imaging andobservation system based on infrared FPA staring imaging technique were analyzed inthis thesis.Starting with an in-depth analysis of the optical-electronic measurement channelof the infrared imaging system, a complete mathematical model of signal transmissionchannel for infrared imaging and observation system was established. The history ofoverall performance evaluation model with its advantages and disadvantages of theinfrared imaging and observation system were reviewed. The previous model wasimproved through the introduction of the CTF (Contrast Transfer Function) of humaneyes, a specific analysis of the capability of multi-band target detection andidentification were carried out. The research result of this thesis is as follows.1. The whole signal transmission channel model was established throughtheoretical analysis; all the physical parameters that influence the imaging quality wereobtained. 2. Aiming at reconstruction the temperature distribution of scene, the ModulationTransfer Function model of all the components in transmission channel was analyzed. Ameasurement uncertainty model of the system was established, and a standardmeasurement method of which is provided too. The method of time-domain filteringand frequency-domain correction method to improve the measurement accuracy ofsystem was put forward and applied in space-frequency domain; the result of highfrequency boost was analyzed also.3. As for the new problem faced on by the thermal FPA imaging technique, theSpurious Response characteristic of under-sampled space model was analyzed,performance decreases with quantity of aliasing was precisely analyzed; since theNETD is not fit for PFA imager, the3-Dimension noise model was provided to describethe sensitivity or SNR.4. The previous model was improved through the introduction of the vision noise,contrast transfer function, and band pass filter of human eyes with analysis of contrastlimit and filter characteristic of human vision. Two kind of target delectabilityperformance model varied with distance were established, one based on the MRT curveand another based on the CTF curve.5. Aiming at the information acquiring of multi-band thermal imager, a method fordecrease the image information redundancy based on the PCA (Principal ComponentAnalysis) was proposed, a calibration method of optical axis coherence in space formulti optical axis image acquisition were given.This thesis is a combination of the theoretical research and engineering applicationsummed and improved by the author with a variety of infrared imaging system designand engineer application, many point of views and methods of which are the progresscome from research of engineering experience by the author, which gives importantvalue for the theoretical analysis, measurement method, and performance improvementfor the overall performance of infrared imaging and observation system, and is withimportant guide value also for target infrared signature research and engineeringapplication of the infrared imaging and observation system...