摘要 |
A method and apparatus for identifying marking holes in an object moving along a conveyor or the like, in which television image signals of the identifying marking holes are classified into signals above and below a threshold level voltage and then made into a monochrome image of the identifying marking holes which is then compared with a pre-memorized image of the marking hole. The invention involves a particular way of selecting the threshold level voltages by using a threshold level voltage from among threshold level voltages used to identify the marking holes in preceding objects according to the frequency of occurrence of the threshold level voltages, and for the threshold level voltage of the second identifying marking hole, initially calculating a target threshold level voltage, and then modifying it if necessary by reference to threshold level voltages used to identify the second marking hole in preceding objects, so as to make the identification of the second hole quicker.
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