| 摘要 |
PURPOSE:To quicken the connection of plural chain codes by providing a chain code memory, an up-down counter, a direction inverting circuit and a sequence designation flip-flop so as to read the chain code in both forward/reverse directions. CONSTITUTION:The sequence designation flip-flop 3 is connected to be set/reset 9 from a system bus 1 via a system bus interface 2. Similarly, the up-down counter 4 is connected in a way capable of being subjected to data load 10 from the system bus 1 and the output of the up-down counter 4 is connected to the address input 17 of the chain code memory 5. The chain code memory 5 is a memory storing chain code constituting lines or line elements, the chain code is a direction code string including the sequence and the direction code is stored in the chain code memory 5 sequentially. Thus, the chain code designates an address storing the 1st direction code, and in incrementing the address, the code is read.
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