To obtain information about a noise-producing sea object under the method applied today, it’s necessary to receive a hydroacoustic noise signal; to complete a time-and-frequency processing of the signal and form three frequency bands at least; to display signal trace indication on a screen. In the newly-patented method, any signal in each frequency band is coded with its own color before displayed. Brightness of each color component is determined by a level of the signal in the respective frequency band. The resulting color is produced upon unification of the components in a common color image in each point of the screen; it’s achieved by mixing the signal levels in the given frequency bands. Type of and distance to a noise-producing body is assessed by comparison of indication signal trace color with the color scale of noise-producing bodies by distance, obtained for existing hydrological conditions.

The method of obtaining color scales for different noise-producing bodies by distance, required to implement the above described method, includes the following procedures. She speed of sound in water in relation to a depth and sea waves on the sea surface are measured. Based on the measured data and known seabed characteristics, signal acoustic field for different noise-producing bodies in each frequency band by distance is calculated. Hydro-acoustic equation is then resolved in a passive mode for each object category with the consideration of the hydrophone tract performance. The data received are then transformed from digital into analog signals which before indication are coded in each frequency band with their own color in a way that the brightness of every color component is determined by the signal level. Based on the hydro-acoustic equation resolution for each point by distance, three color components are united in a single color image on a screen. The obtained image of color scale for each category of noise-producing bodies in relation to distance is then stored as reference values which are then compared in a sail with the data received based on the newly-patented method to identify what and where makes noise.

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