Table 8. Pre-processing technologies.

Ref. No.	Technologies
R3	Zoom out images; Rotation and crop
R5, R29	Image resize and data labeling
R6	A time-synchronized preprocessing method based on the RGB morphology and radar spectrum differences
R9	Converted to tokens using a Pixel Encoder
R12	Hybrid median filter
R15	Star RGB
R17	Transfer learning
R25	Suppress noise (i.e., data smoothing) using Average Filter, Median Filter, and Butterworth Filter
R28	Generative adversarial networks (GAN)
R35	Compress input video stream
R43	Data augmentation: translation and noise injection
R44	Median filtering
R46	Luminosity method based on gray-scale conversion of the input image