Study On Automatic Scaling Of The F Layer Traces In Ionogram

Ionospheric sounding is an important content for the research of near-earth space environment, also has significant meaning on radio communication and environmental monitoring. As the development of detection technique and updating of equipment, the amount of ionospheric data is becoming larger than ever before. The assignment of monitoring and predicting ionosphere also requires higher demand on real time data. The traditional way of obtaining the ionospheric parameters by manual method could not satisfy the actual demand. Thus, automatic scaling of ionogram plays an important role in ionospheric research, which has been a topic full of scientific interest for ionospheric researchers for a long time. Drawing on the experiences of other methods of ionogram scaling, a new method for scaling the F layer traces in ionogram based on the image recognition is proposed and described in this paper. And the algorithm according to the morphological characters of ionogram layers summarized from the basic knowledge of ionospheric vertical sounding. The work mainly contains:1. The background information of ionospheric sounding are introduced, which includes the definition of the ionospheric parameters in ionogram and the summary of existing scaling methods, laying foundation for the research on scaling algorithm. According to the analysis of ionospheric basis knowledge, we confirm the research content and research sense of this subject and propose the overall flow of algorithm. The proposed algorithm include two steps: location and recognition of the F layer traces in ionogram and scaling of the F layer traces.2. Based on the realization of ionogram, we know that the key of ionogram scaling is to locate and distinguish the ionospheric traces precisely. Thus, a method for the location and recognition of the ionospheric traces in ionogram was proposed, which includes pretreatment of ionogram on the basis of image segmentation and morphological filtering, calibration of image target consists of determination of the frequency range and labeling of connected components, recognition of the F layer traces utilizing the integral projection.3. Scale the F layer traces obtained by the previous step. This algorithm includes image noise removal by PDE model and morphological filter, identification of the traces of O/X in the main body of F layer on the basis of skeletonization and detection of key points, measurement of the critical frequency of F layer.In this paper, we have performed a series of experiments to confirm the effectiveness and feasibility of the method for location and scaling the F layer traces in ionogram.