A high-concealment
signal detection method,
system, device and medium based on a digital residual image, the sampled
signal IQ data is preprocessed, that is, the key parameters including the observation bandwidth (that is, the sampling rate), the frame length, the overlap rate and the time and
frequency resolution are set; at the same time, each frame of
signal is subjected to windowing filtering
processing, and the
system automatically determines the segmentation number according to the signal length; then, each signal segment is subjected to
fast Fourier transform, and the calculation result is stored in a
bitmap database; then, the
frequency spectrum data is continuously superimposed in the
bitmap database, based on the total superposition number, the proportion of each
cell is calculated to form a probability
density distribution matrix, the probability
density distribution matrix is subjected to normalization
processing, and all probability values are ensured to be located between 0 and 1; by using a self-defined mapping table, the normalized probability
density matrix is converted into a digital residual image through linear mapping; finally, by using a method combining
Gamma correction and median filtering, the digital residual image obtained through mapping is further enhanced, and a final clear and smooth digital residual image is obtained; in the application, the
Gamma correction can effectively enhance the darker part to improve the
image contrast, the median filtering can effectively remove the
salt and pepper noise generated by image mapping, and the important edges and details of the signal in the image are retained; due to the low calculation complexity, the application is suitable for real-
time processing and meets the
low complexity requirement.