Abstract: The teachings herein provide a method and apparatus for detecting erroneous pixel addressing in an imaging sensor. The method and apparatus advantageously leverage the characteristic “fixed pattern noise” of the sensor to detect addressing errors. Broadly, pixel addressing errors are detected based on comparing the pattern noise seen in data read outs from a targeted address of the sensor with characteristic fixed pattern noise known for the sensor.

Abstract: In one aspect, this disclosure presents a method and apparatus for verifying that minimum object contrast requirements are met within a region representing a volume to be monitored by a machine vision system. In complementary fashion, the disclosure also presents a methodology for constraining the positions of the lighting sources to be used for illuminating the monitored volume at a minimum height above the floor, and for the use of a key light that provides asymmetrical lighting within the monitored volume relative to the camera(s) used for imaging the monitored volume. Correspondingly, the disclosure also presents a method and apparatus for monitoring for proper operation of the key light and responding to improper operation. The minimum contrast verification and key light monitoring operations can be implemented using standalone apparatuses, or can be incorporated into the machine vision system.

Abstract: According to one aspect of the teachings presented herein, a machine vision system includes one or more sensor units that are each advantageously configured to use different pairings among a set of spaced-apart image sensors, to provide redundant object detection for a primary monitoring zone, while simultaneously providing for the detection of objects that may shadow the primary monitoring zone. Further, a plurality of “mitigations” and enhancements provide safety-of-design and robust operation. Such mitigations and enhancements include, for example, bad-pixel detection and mapping, cluster-based pixel processing for improved object detection, test-image injection for fault detection, dual-channel, redundant processing for safety-critical object detection, temporal filtering to reduce false detections, and the use of high dynamic range (HDR) images, for improved operation over variable ambient lighting conditions.