PURPOSE: To perform reading operation when the quantity of light is optimum and perform the reading operation accurately by deciding on the level of an image signal from a reference object.
CONSTITUTION: When a readout object 2 is read, a light emitting body 3 is turned on to illuminate the reference object 1. At the point of time, the image signal obtained by an image sensor 5 is supplied to a level decision part 7 to decide on the image signal level, thereby deciding on the range of the quantity of read light, i.e. output light of the light emitting body 3. Then when the quantity of the output light of the light emitting body 3 becomes enough to make a read, the readout object body 2 is read. Consequently, even if the light emitting body varies in the quantity of light when turned on, the readout object 2 is read with the quantity of light suitable for the reading, so the object is read excellently.
KIKUCHI OSAMU
MATSUMOTO HIROSHI
OTSUBO OSAMU
ITO SHOICHI
HITACHI ENG CO LTD
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