Automatic classification of spread‐F types in ionogram images using support vector machine and convolutional neural network - Phongsachot Benchawattananon; Apirat Siritaratiwat; Pornchai Supnithi; Michi Nishioka; Septi Perwitasari; Puripong Suthisopapan; A. Kruesubthaworn (Earth, Planets and Space, 2024)