| 摘要 |
PURPOSE:To detect duplicated read-in by two sensors, by taking the difference between the number of video elements read in with one sensor and two sensors. CONSTITUTION:A shorter mark than the range of read-in with one linear sensor is read-in with one sensor X, and the data of mark at this time is temporarily stored in a memory 21a. The data stored in the memory 21a is sequentially read-in, the number of video elements of mark is counted with counters 25a-27a, and it is latched with a latch circuit 33 via an adder 28 and data selector 30. Further, the same mark is read-in with sensors X, Y, the data at this time is temporarily stored in memories 21a, 21b, the respective video element number is counted, it is added with an adder 28 and latched with a latch circit 35. Further, the data of both the latch circuits 33, 35 is inputted to a subtractor 38 to take the differnce of both data. This difference is the number of video elements in duplicated read-in. |
