High - Resolution Image Quality Evaluation Of Solar Chromosphere

High resolution solar chromosphere images are of great significance to the astronomers involved in the study of the sun. To restrain the negative effect of atmospheric turbulence on image quality and obtain superior solar chromosphere images, the technique of consecutive short exposure is applied in astronomical observation to capture short exposure serial images, with the ones of higher quality chosen for reconstruction. Therefore, a proper image quality evaluation method is of immense value in the process of image choosing and later reconstruction.Based on the analysis of the characteristics of many high resolution solar chromosphere images,14 non-reference image quality evaluation methods are applied to evaluate the quality of chromosphere images, and suitable methods are chosen through a comparative analysis of the experimental results. The evaluation experiment is divided into two parts. First, the 14 methods are applied to decide the quality of each chromosphere image. Then four methods that show favorable results are chosen from those 14 methods, including MFGS method, spectral ratio method, average gradient method and RMS-contrast method. Second, the above-mentioned four evaluation methods are applied to evaluate 5 groups of serial images, which are of diverse qualities, provided by YNST in Yunnan Observatory of CAS. The result shows that MFGS method and spectral ratio method are most suitable for the evaluation of chromosphere images with MFGS method appropriate to evaluate those low quality images and spectral ratio method for those high quality images.In the light of the evaluation experiment results, a new combination of frames-selection, characterized by the application of MFGS method first to remove low quality images and then the spectral ratio method for frames-selection and reconstruction of the filtered images, is proposed in this thesis in accordance with the unique properties of MFGS method and spectral ratio method. A comparative experiment of the combined method and the spectral ratio method for frames-selection shows that better images are obtained after frames-selection and reconstruction by applying the combined method.