| 摘要 |
PURPOSE:To have automatic decision of the threshold value for the brightness to an appropriate value by setting a wind within an zone including the worn part of a tool, the other part of tool and the backdrop to the tool, and by measuring the brightness distribution of the image in this zone of wind. CONSTITUTION:The zone A of a wind 5a including the worn part W of a tool 2a, a wind 5b including this zone A and extended to the zone B including the other part g than worn part of the tool 2a and the backdrop b to the tool 2a, and a wind 5C till the zone C enlarged to the zone including the backdrop b according to necessity are established, and the brightness distribution in each wind zone is computed. Obtained brightness distributions are compared, and a brightness threshold value is set between the zone in which the brightness distributions vary to each other and the zone in which they do not make relative variation, and thereby making the image information in two values can be performed properly. |
