| 摘要 |
PURPOSE:To simply correct the resolution and especially to correct deterioration in the resolution due to deteriorated flatness of an installed location by measuring the resolution of picture information based on a digital signal and displaying the result of measurement. CONSTITUTION:After a prescribed pre-processing, a CPU 24 scans a lighting lamp and a reflecting mirror in a prescribed direction and reads a picture of an original by a line sensor 9. A picture signal of the line sensor 9 is converted into a digital signal by an A/D converter 20. Then the picture signal subjected shading correction by a shading correction circuit 21 passes through a picture processing section 23. A contrast measurement circuit 22 is provided with a maximum value detection circuit, a minimum value detection circuit and a contrast arithmetic operation circuit or the like. Then the contrast at four points, that is, this side of scanning and the depth side in the subscanning direction, a scanning start point and a scanning end pint in the main scanning direction is calculated and the result is displayed on an LCD 16. The resolution is adjusted and corrected by observing the display by displaying the result of measurement in this way. |
