| 摘要 |
PURPOSE:To eliminate the influence of variation in the quantity of light by obtaining binary coding image data by comparing a reference signal of every specific level for binary coding with an image signal, and calculating the high- low level ratio of each level and variation in rate from said binary coded image data and making a level judgement. CONSTITUTION:The image signal from an industrial television 1 is inputted to the plus-side terminal of a comparator 14 and the reference signal for binary coding which varies at every specific level is inputted to the minus-side terminal from a binary coding reference data transmission part 11; and its output binary- coded image data is stored in a frame memory 16 through a TTL inverter 15. Further, an evaluated value arithmetic part 21 calculates the number of high-level dots and the number of low-level dots of each level from the image data. Further, the arithmetic part 21 calculates the ratio of both dots and the increase rate to binary-coding level variation to calculating an evaluated value for each level of the reference data for binary coding from both values by a specific expression, and then judging the level at which the evaluated value is minimum as a binary coding level for position detection. |
