The invention relates to a computer-implemented method for the optical sensing, the detection and the quantification of relevant conditions and/or their changes with respect to at least one target object, wherein at least one target object is temporarily positioned opposite an optical sensor device and wherein the fault conditions of the fault classes deviate from the optimal state. The method is characterized particularly in that the background and the target object are distinguished by means of a higher rate of change of the image information of the background in comparison with the rate of change of the image information of the target object.