Safety system vision sensor and relative operating method

There is described a safety system (1) having a hazard area (2) containing a reference pattern (3), and a vision sensor (4) having an acquisition module (5) for acquiring an image containing the reference pattern (3) in an area portion (P) of the hazard area (2); a memory (6) containing a number of discrimination thresholds (SCi) related to respective predetermined light ranges (Li); and a number of computing modules (Ai), each of which has a binarization module (Bi) for discriminating the pattern in an image section (11) as a function of a respective discrimination threshold (SCi), and a decision module (Ci) which determines a non-intrusion state when a predetermined match is found between the discriminated pattern and the reference pattern; the sensor (4) also having a generating module (12) which determines a non-intrusion condition when at least one of the computing modules (Ai) determines a non-intrusion state.