System for assessing stochastic properties of signals representing three items of mutually orthogonal measurement information

A signal processing system comprising:

• means, including a transducer means, for receiving an analog signal which includes an information component and a noise component and for processing the analog signal to provide a digital signal comprising sample point measurements representing three mutually orthogonal items of measurement information, said sample point measurements being generated for a series of symbolic, three-dimensional spatial apertures relative to a symbolic three-dimensional spatial reference system;
• an information processing sub-system for receiving said digital signal and for processing it to extract said information component;
• a noise likelihood determination sub-system for receiving said digital signal and for generating a random noise assessment that the digital signal comprises random noise, the noise likelihood determination sub-system controlling the information processing sub-system in response to the random noise assessment, the random noise assessment being further generated in response to a nearest-neighbor distance deviation assessment generated in response to nearest-neighbor ones of the sample points in comparison with distances of the most direct linear spans across the symbolic three-dimensional reference space between a like number of nearest-neighbor reference points that are randomly distributed, the nearest-neighbor distance deviation further being generated for a plurality of selected sample point populations, each such selected population comprising a plurality of "N" sample point measurements, the random noise assessment further being generated in response to a standard significance test in connection with the nearest-neighbor distance deviation assessments generated for said populations;
• said noise likelihood determination sub-system further including reference point distance determination means for generating an expected average distance value .mu..sub.r between reference points within a corresponding selected symbolic three-dimensional reference spatial region containing a sample point population as ##EQU7## where ".rho." represents the three-dimensional spatial density of reference points in the selected region;
• said noise likelihood determination sub-system still further including sample point distance determination means for generating an average nearest-neighbor sample point distance value as ##EQU8## where "min(d.sub.ij)" corresponds to a minimum distance of such most direct lineal span across the symbolic three-dimensional reference space between sample points identified by indices "i" and "j" ;
• and
• said noise likelihood determination subsystem yet further including nearest-neighbor distance deviation assessment generating means for generating the nearest-neighbor distance deviation assessment value as ##EQU9## where ##EQU10##