Sense Level Adjustment Device for Image Scanning Machine
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
To enable an operator of an image scanning machine to easily adjust a sense level of the machine without a test chart, a device is provided for rapidly and accurately obtaining an average voltage of white level of the sensed image signals regardless of the degree of coarseness of the form surface being scanned. In Fig. 1, an image sensor 1 for optically scanning a form 2 generates outputs as voltage signals through an pre-amplifier 3. Depending on the intensity of the light from the form surface, the voltage signals vary in amplitude with respect to the black reference level. Also, as shown in Fig. 2, the signals at the white level are slightly varied depending on the reflectance of the form surface.