Sunspot drawings handwritten character recognition method based on deep learning

• Convolution neural network (CNN) is applied to recognize handwritten characters in scanned sunspot drawings.
• A recognition model for handwritten characters is obtained by CNN method.
• The daily full-disc sunspot numbers and full-disc sunspot areas can be obtained from the recognized information.

High accuracy scanned sunspot drawings handwritten characters recognition is an issue of critical importance to analyze sunspots movement and store them in the database. This paper presents a robust deep learning method for scanned sunspot drawings handwritten characters recognition. The convolution neural network (CNN) is one algorithm of deep learning which is truly successful in training of multi-layer network structure. CNN is used to train recognition model of handwritten character images which are extracted from the original sunspot drawings. We demonstrate the advantages of the proposed method on sunspot drawings provided by Chinese Academy Yunnan Observatory and obtain the daily full-disc sunspot numbers and sunspot areas from the sunspot drawings. The experimental results show that the proposed method achieves a high recognition accurate rate.