Time of flight system and method for safety-rated collision avoidance

A method for automated collision avoidance, comprising:

• emitting, by a three-dimensional camera mounted on a front side of an automated moving machine at a downward tilt, light pulses into a monitored area in front of the automated moving machine, wherein the downward tilt is such that a portion of a ground or floor in front of the automated moving machine is within a field of view of the three-dimensional camera;
• for respective pixels of a pixel array of the three-dimensional camera, generating, by the three-dimensional camera, electrical energy proportional to a subset of the light pulses received at the respective pixels from surfaces within the monitored area;
• determining, by the three-dimensional camera, measured distance values dso associated with the respective pixels based on analysis of the electrical energy;
• determining, by the three-dimensional camera, calculated distance values dvo associated with the respective pixels based on the measured distance values dso associated with the respective pixels, field of view angles β of the respective pixels, and an inclination angle α of the three-dimensional camera;
• and
• in response to determining that at least a subset of the calculated distance values dvo satisfy a defined criterion indicative of a presence of an obstacle within a protective field of the three-dimensional camera, initiating, by a collision avoidance system comprising a processor, a safety action that alters operation of the automated moving machine to mitigate a collision with the obstacle.

A non-transitory computer-readable medium having stored thereon instructions that, in response to execution, cause a collision avoidance system to perform operations, the operations comprising:

• emitting light pulses from a three-dimensional camera into a monitored area in front of a mobile asset, wherein the three-dimensional camera is angled downward such that a portion of a ground or floor in front of the mobile asset is within a field of view of the three-dimensional camera;
• for respective pixels of a pixel array of the three-dimensional camera, generating electrical energy proportional to a subset of the light pulses received at the respective pixels from surfaces within the monitored area;
• determining measured distance values dso associated with the respective pixels based on analysis of the electrical energy;
• determining calculated distance values dvo associated with the respective pixels based on the measured distance values dso associated with the respective pixels, field of view angles β of the respective pixels, and an inclination angle α of the three-dimensional camera;
• and
• in response to determining that at least a subset of the calculated distance values dvo satisfy a defined criterion indicative of a presence of an obstacle within a protective field of the three-dimensional camera, initiating a safety action that alters operation of the mobile asset to mitigate a collision with the obstacle.