| 摘要 |
PURPOSE:To rapid and exactly detect an illumination field by comparing data obtained by the addition and the tabulation of picture data in an X and a Y axis directions set along with the rectangular outline of the illumination field and a prescribed threshold value. CONSTITUTION:A digital picture data at each position on an accumulating fluorescent body sheet 10 is obtained from picture information obtained by a look-ahead reading. At the next, the above picture data are added and tabulated in the X and the Y axis directions set on the sheet 10 along with two sides 12a and 12b neighboring the outline of a rectangular illumination field 12. And next, by comparing the added and tabulated data with a threshold Th set in advance, positions A and B, and C and D in the X and the Y axis directions where the above added and tabulated data are at high levels are found. And an area enclosed with straight lines (a) and (b) in the X axis direction on the positions A and B and straight lines (c) and (d) in the Y axis direction on the positions C and D on the Y axis is decided as the illumination field 12. |
