The invention relates to a method, a computer program product and a machine vision system (30), comprising at least one lighting device (34), at least one image sensor (31 a-c) and a data processing device (32), the system in a first mode illuminating a first object (35) using a first type of illumination and capturing images of the first object at a first image capturing frequency, when the first object (35) is on a second object (33), transmitting the captured image data to the data processing device for analysis, and changing the system for monitoring the second object in a second mode, if absence of the first object on the second object is detected from the image data, wherein said at least one image sensor (31 a-c) is reconfigured to capture images at a second image capturing frequency from the second object.