Fig. 4From: Classification of the equatorial plasma bubbles using convolutional neural network and support vector machine techniquesSamples of quick look (QL) plot images collected by VHF radar with the x-axis represent Doppler frequency (Hz) and the y-axis represent range (kilometers) (a) without plasma bubble (b) with unsure structure [cannot be identified as EPB or due to system errors] (c) with plasma bubblesBack to article page