Research On Image Quality Assessment Method Based On Wave-front Aberrations

In the information-based society, the image has become an important source of information. While, people’s requirement on the quality assessment of image becomes higher and higher and image quality assessment technology has become particularly important.Although subjective quality assessment of image is the most direct method, it limited by personal factors. Objective quality assessment of image is simple and convenient, but the human visual perception is often ignored. A perfect image quality evaluation method should not only can evaluate the image quality accurately but also can reflect the human subjective visual perception. In order to construct image quality evaluation method which conforms to human visual characteristic we do the following research:Firstly, according to the actual aberration, corneal parameters, and the axial spacing of human eyes, we construct individual human eye models which have the same optical properties with real eyes. Through the analysis of the spot diagrams, modulation transfer function curves and diffraction images, we conclude that the root mean square of radius of the spot diagrams increase with the rising of the aberrations and the modulation transfer function curve is more and more close to the modulation transfer function curve of the diffraction limit, the diffraction images is becoming clear. And with the decrease of the aberration, the root mean square of radius of the spot diagrams becomes smaller, modulation transfer function curve is more and more far away from the modulation transfer function curve of the diffraction limit, the diffraction images is becoming fuzzy.Secondly, using actual aberration data, image quality evaluation models which conforms to the human eye visual features are set up. We evaluated ordinary gray images and noise images to verify the accuracy and effectiveness of these models. Result shows that this method is feasible and effective. Evaluations of different eyes on the same image are different, and the smaller the human eye aberration is the clearer the image we observe. This method not only can reflect the subjective perception of the human eye, but also to present the actual images in different eyes intuitively.Finally, the effect of aberrations has been analyzed by using the contrast sensitivity curve. Data analysis shows that, with the increase of wave-front aberration of human eye, the contrast sensitivity is more and more low, and the images we observed is fuzzier, which explains the effects of aberration on image quality assessment.