1. A method for detection of object faults, in real time, and comprising the steps of: scanning an object to be checked and detecting luminance levels of each of a finite number of dots thereof to provide analog image signals corresponding to each dot and indicative of said luminance levels; converting said analog signals to corresponding digital signals according to a luminance level scale and storing said digital signals in a memory to provide a digitized object image; dividing said digitized object image into a predetermined number of areas having a predetermined number of said dots; calculating standard deviations for digitized luminance values of the dots of each area into which the digitized object image has been divided according to the formula: ##EQU5## wherein: x.sub.1 =luminance value of the individual dots pertaining to an area, and n=number of dots in the area; storing said standard deviations of said areas; providing digitized reference standard deviation values corresponding to each of said areas; comparing each of said standard deviations with said corresponding digitized reference standard deviation values; and providing a fault signal when a threshold is exceeded during said comparing.