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3.6.9 Noise Removal
This image filter reduces the noise (black spots) of images. Noise is caused by particles of carbon
deposited from the printing by the copier or fax machine and by dirt and other foreign matter on the
documents when they are scanned.
When noise is removed from the text areas, the dots over the letters “i” and “j” and other information may
also be removed in error. To correct this, select a value larger than the gap between the dots and other
parts for the minimum gap setting.
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Note
When the Noise Removal and Crop functions are applied to the same image, better results are
yielded when Noise Removal is applied first. In order to obtain the optimum image quality and speed,
it is recommended that the settings of the image filters be adjusted while scanning an actual
document. Depending on the images being scanned, this function may not function properly.
Property
Description
Max height
The maximum height of what is to be considered as noise is set here. Inches,
millimeters or points can be used as the unit for the setting. Input “mm” or “pt”
after the number, respectively. A fraction such as 1/1 00 can also be specified
as the number.
Max width
The maximum width of what is to be considered as noise is set here. Inches,
millimeters or points can be used as the unit for the setting. Input “mm” or “pt”
after the number, respectively. A fraction such as 1/1 00 can also be specified
as the number.
Max area
The area which is smaller than a percentage of the area defined by Maximum
Height and Maximum Width is to be considered as noise. This percentage is
set here. Normally, a setting of 100 is selected.
Min separation
The gap between what is considered as noise and other characters, etc. is set
here. When the gap is too small, the dots over the letter “i” and other marks are
considered as noise and removed. Inches, millimeters or points can be used as
the unit for the setting. Input “mm” or “pt” after the number, respectively. A
fraction such as 1/4 can also be specified as the number.
Table 14: Noise Removal Properties and Descriptions