The Quality Assessment Of H-alpha Full Disk Solar Image Based On Limb Darkening Profile

H-alpha full disk observation is very important in solar physics. There are many telescopes doing this observation regularly and producing massive images. Like the Global Oscillation Network Group (GONG) project is unified release the six observatory station of the minutes of h-alpha full disk observation data every day, the domestic national astronomical observatory of the huairou solar observing station also in doing this observing.However, the qualities of these images are different due to the change of observation condition, such as seeing, cloud and so on. Images with bad quality will necessarily bring difficult to the subsequent research.So, if we can do an early image quality assessment to these images, we will greatly improve the use efficiency of the data and get a better scientific output, provide a strong basis of support for the scientific research.In this paper, we in view of the GONG project and the huairou solar observing station of observing h-alpha full disk solar images, according to that these images with the feature of limb darkening, we proposed two image quality assessment algorithms to evaluate these images. The first method is the use of the kurtosis of the limb darkening curve to evaluate its data quality.According to this method, we designed six evaluation from three angles, they are maximum normalized limb darkening curve, the center normalized limb darkening curve and whether to calculate the weighted kurtosis or not. Combine with the GONG project50sets of experimental data results which were analyzed, we determined a better evaluation, whitch was the calculation of the maximum normalized limb darkening curve kurtosis as the evaluation index.Then we used this evaluation index to evaluate6groups of image data from huairou solar observing station. The second method is the use of an image of four mean limb darkening curves,we choosed the smallest correlation coefficient as the evaluation index.After that we used this method to evaluate the image observed by the GONG project and the huairou solar observing station. By comparison of the subjective evaluation and the objective evaluation, we confirmed that the change of the observing conditions and the block of the field of view will influence the limb darkening curve kurtosis and curve correlation.Nearly20000H-alpha full disk solar images from GONG project was processed and thousands of poor quality images were detected automatically. Also, nearly1000poor quality images form huairou solar observing station were detected.Some typical cases were explained in details. We conclude that these assessments are successful and effective.At the end of this paper, the insufficient of these methods has been carefully discussed too.